Developing device

Abstract

A developing device includes a first rotatable member, a first magnet, a second rotatable member, and a second magnet. A position on the surface of the second rotatable member at which the magnetic flux density of the receiving magnetic pole is maximum is a point T, a position on the upstream side is a point Hu, and a position on the downstream side is a point Hd, among the respective positions at which the magnetic flux density of the receiving magnetic pole is half of the maximum value. When an angle formed by a straight line L20 connecting a rotation center R2 of the second rotatable member and a point T and a straight line L21 connecting the rotation center R2 and a point Hu is w [theta] 21, and an angle formed by L20 and a straight line L22 connecting R2 and Hd is w [theta] 22, the following relationship is satisfied: w [theta] 22-w [theta] 21 > = 0.

Description

Technical Field The present invention relates to a developing device for developing an electrostatic latent image formed on an image bearing member with a developer. Background Art As a developing device, a configuration is proposed in which two developing rollers for developing an electrostatic latent image formed on an image bearing member using a developer are arranged side by side with respect to the rotation direction of the image bearing member (U.S. Patent Application Publication No. 2013 / 0330107). In the developing device disclosed in US2013 / 0330107 A1, of the two developing rollers, the developer is supplied from a supply portion to a first developing roller positioned at a lower portion in the vertical direction, and the developer is conveyed from the first developing roller positioned at the lower portion to a second developing roller positioned at an upper portion in the vertical direction. As described in US2013 / 0330107 A1, in the case where the developer is transported from the first developing roller to the second developing roller positioned at the upper portion in the vertical direction, the developer is transported by a magnetic field formed between a transporting magnetic pole of a first magnet disposed in the first developing roller and a receiving magnetic pole of a second magnet disposed in the second developing roller. The transporting magnetic pole is opposite in polarity to the receiving magnetic pole. In this configuration, when the second developing roller rotates in a direction opposite to that of the first developing roller in a position where the second developing roller is opposed to the first developing roller, the polarity of the first magnetic pole adjacent to the transporting magnetic pole on the upstream side of the transporting magnetic pole is opposite to the polarity of the second magnetic pole adjacent to the receiving magnetic pole on the downstream side of the receiving magnetic pole. Therefore, a magnetic field is generated between the first magnetic pole and the second magnetic pole for attracting the developer to each of the rollers. Therefore, a magnetic field for attracting the developer is generated between the first magnetic pole and the second magnetic pole, and the magnetic field is likely to cause the developer to move between the first magnetic pole and the second magnetic pole. In addition, when the developer movement is generated between the first magnetic pole and the second magnetic pole, the moving developer is likely to float and then deposit on the image bearing member positioned near the first developing roller and the second developing roller. Therefore, when the developer is deposited on the image bearing member, image defects such as vertical streak-like fog may appear on the output image. Summary of the invention A main object of the present invention is to provide a developing device capable of suppressing the occurrence of image defects. According to one aspect of the present invention, there is provided a developing device, the developing device comprising: a developing container, the developing container being configured to contain a developer including a toner and a carrier; a first rotatable member, the developer contained in the developing container being supplied to the first rotatable member, the first rotatable member carrying and feeding the developer to a first developing position, where an electrostatic latent image formed on an image bearing member is developed; a first magnet, the first magnet being fixedly and non-rotatably disposed inside the first rotatable member, wherein the first magnet comprises a first developing magnetic pole disposed opposite to the image bearing member at the first developing position, a conveying magnetic pole disposed downstream of the first developing magnetic pole with respect to a rotation direction of the first rotatable member, and a first feeding magnetic pole disposed upstream of the conveying magnetic pole with respect to the rotation direction of the first rotatable member and adjacent to the conveying magnetic pole, the first feeding magnetic pole having a magnetic polarity different from that of the conveying magnetic pole; a second rotatable member disposed opposite to the first rotatable member, through the first rotatable member a magnetic field generated by a magnet to transport the developer from the first rotatable member to the second rotatable member, wherein the second rotatable member carries and feeds the developer to a second developing position, develops the electrostatic latent image at the second developing position, and wherein a rotation direction of the second rotatable member at a position on the outer peripheral surface of the second rotatable member at which the second rotatable member is closest to the first rotatable member is opposite to the rotation direction of the first rotatable member at a position on the outer peripheral surface of the first rotatable member at which the first rotatable member is closest to the second rotatable member; and a second magnet, the second magnet being fixedly and non-rotatably arranged inside the second rotatable member, wherein the second magnet includes a plurality of magnetic poles, the plurality of magnetic poles including: a second developing magnetic pole arranged opposite to the image bearing member at the second developing position; a receiving magnetic pole, the receiving magnetic pole being arranged upstream of the second developing magnetic pole with respect to the rotation direction of the second rotatable member and having a magnetic polarity different from that of the transporting magnetic pole;and a second feeding magnetic pole, which is arranged downstream of and adjacent to the receiving magnetic pole with respect to the rotation direction of the second rotatable member and has a magnetic polarity different from that of the receiving magnetic pole, the receiving magnetic pole being a magnetic pole arranged closest to the feeding magnetic pole among the plurality of magnetic poles, wherein a position at which a magnetic flux density of the receiving magnetic pole in a normal direction relative to the outer peripheral surface of the second rotatable member is a maximum on the outer peripheral surface of the second rotatable member is point T, and a position at which a magnetic flux density of the receiving magnetic pole in a normal direction relative to the outer peripheral surface of the second rotatable member is a half-value of the maximum on the outer peripheral surface of the second rotatable member is located relative to the second rotatable member. The position on the upstream side of the rotation direction of the rotating member is point Hu, the position on the downstream side of the rotation direction of the second rotatable member among the positions on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is half the maximum value is point Hd, the angle formed by the straight line L20 connecting the rotation center R2 of the second rotatable member and the point T and the straight line L21 connecting the rotation center R2 and the point Hu is wθ21, and the angle formed by the straight line L20 and the straight line L22 connecting the rotation center R2 and the point Hd is wθ22, the following relationship is satisfied: wθ22-wθ21≥0. ; According to another aspect of the present invention, there is provided a developing device, the developing device comprising: a developing container, the developing container being configured to contain a developer including a toner and a carrier; a first rotatable member, the developer contained in the developing container being supplied to the first rotatable member, the first rotatable member carrying the developer and feeding it to a first developing position, where an electrostatic latent image formed on an image bearing member is developed; a first magnet, the first magnet being fixedly and non-rotatably disposed inside the first rotatable member, wherein the first magnet comprises a first developing magnetic pole disposed opposite to the image bearing member at the first developing position, a conveying magnetic pole disposed downstream of the first developing magnetic pole with respect to a rotation direction of the first rotatable member, and a first feeding magnetic pole disposed upstream of the conveying magnetic pole with respect to the rotation direction of the first rotatable member and adjacent to the conveying magnetic pole, the first feeding magnetic pole having a magnetic polarity different from that of the conveying magnetic pole; a second rotatable member disposed opposite to the first rotatable member, The magnetic field generated by the first magnet transports the developer from the first rotatable member to the second rotatable member, wherein the second rotatable member carries and feeds the developer to a second developing position, develops the electrostatic latent image at the second developing position, and wherein the rotation direction of the second rotatable member at a position on the outer peripheral surface of the second rotatable member at which the second rotatable member is closest to the first rotatable member is opposite to the rotation direction of the first rotatable member at a position on the outer peripheral surface of the first rotatable member at which the first rotatable member is closest to the second rotatable member; and a second magnet, the second magnet being fixedly and non-rotatably arranged inside the second rotatable member, wherein the second magnet includes a plurality of magnetic poles, the plurality of magnetic poles including: a second developing magnetic pole arranged opposite to the image bearing member at the second developing position; a receiving magnetic pole, the receiving magnetic pole being arranged upstream of the second developing magnetic pole with respect to the rotation direction of the second rotatable member and having a magnetic polarity different from that of the transporting magnetic pole;and a second feeding magnetic pole, the second feeding magnetic pole being arranged downstream of the receiving magnetic pole with respect to the rotation direction of the second rotatable member and adjacent to the receiving magnetic pole and having a magnetic polarity different from that of the receiving magnetic pole, the receiving magnetic pole being a magnetic pole arranged closest to the feeding magnetic pole among the plurality of magnetic poles, wherein a position on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is a maximum value is point T, a position on the upstream side with respect to the rotation direction of the second rotatable member among the positions on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is a half-value of the maximum value is point Hu, and a position on the downstream side with respect to the rotation direction of the second rotatable member among the positions on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is a half-value of the maximum value is point Set as point Hd, and wherein, in a graph in which the ordinate represents the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member, and the abscissa represents the angle of the second rotatable member relative to the rotation direction of the first rotatable member, a straight line passing through the point T and parallel to the abscissa is a straight line HLt, a straight line passing through the points Hu and Hd and parallel to the abscissa is HLh, a straight line passing through the point Hu and parallel to the ordinate is VL21, a straight line passing through the point Hd and parallel to the ordinate is VL22, an area of ​​a rectangle surrounded by the straight lines VL21, VL22, HLt and HLh is S, and in the region of the rectangle, an area obtained by integrating the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member from the straight line VL21 to the straight line VL22 according to the angle of the second rotatable member relative to the rotation direction of the second rotatable member is an area Sa, the following relationship is satisfied: Sa / S≥75%. ; According to another aspect of the present invention, there is provided a developing device, the developing device comprising: a developing container, the developing container being configured to contain a developer including a toner and a carrier; a first rotatable member, the developer contained in the developing container being supplied to the first rotatable member, the first rotatable member carrying and feeding the developer to a first developing position, where an electrostatic latent image formed on an image bearing member is developed; and a first magnet, the first magnet being fixedly and non-rotatably disposed inside the first rotatable member, wherein the first magnet comprises a first developing magnetic pole disposed opposite to the image bearing member at the first developing position, a first magnetic pole being disposed opposite to the rotation of the first rotatable member, and a first magnetic pole being disposed opposite to the rotation of the first rotatable member. a conveying magnetic pole disposed downstream of the first developing magnetic pole in a direction thereof and a first feeding magnetic pole disposed upstream of the conveying magnetic pole with respect to the rotation direction of the first rotatable member and adjacent to the conveying magnetic pole, the first feeding magnetic pole having a magnetic polarity different from that of the conveying magnetic pole; a second rotatable member disposed opposite to the first rotatable member, conveying the developer from the first rotatable member to the second rotatable member by a magnetic field generated by the first magnet, wherein the second rotatable member carries and feeds the developer to a second developing position, develops the electrostatic latent image at the second developing position, and wherein the second rotatable member is closest to the second rotatable member on an outer peripheral surface of the second rotatable member. The rotation direction of the second rotatable member in the position of the first rotatable member is opposite to the rotation direction of the first rotatable member in the position where the first rotatable member is closest to the second rotatable member on the outer peripheral surface of the first rotatable member; and a second magnet, the second magnet is fixedly and non-rotatably arranged inside the second rotatable member, wherein the second magnet includes a plurality of magnetic poles, the plurality of magnetic poles including: a second developing magnetic pole arranged opposite to the image bearing member at the second developing position; a receiving magnetic pole, the receiving magnetic pole is arranged upstream of the second developing magnetic pole with respect to the rotation direction of the second rotatable member and has a magnetic polarity different from the magnetic polarity of the conveying magnetic pole; and a second developing magnetic pole. a feeding magnetic pole, the second feeding magnetic pole is arranged downstream of the receiving magnetic pole with respect to the rotation direction of the second rotatable member and adjacent to the receiving magnetic pole and has a magnetic polarity different from that of the receiving magnetic pole, the receiving magnetic pole being a magnetic pole arranged closest to the feeding magnetic pole among the plurality of magnetic poles, wherein a position on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is a maximum value is point T, and in each position on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is a half value of the maximum value,A position located on the upstream side with respect to the rotation direction of the second rotatable member is a point Hu, and a position located on the downstream side with respect to the rotation direction of the second rotatable member is a point Hd among the positions on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is half the maximum value, and wherein the ordinate represents the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, and the abscissa represents the magnetic flux density of the second rotatable member with respect to the rotation direction of the second rotatable member. In the graph of the angle, among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 10% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position located on the upstream side with respect to the rotation direction of the second rotatable member is point Cu, and the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 10% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member. Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is 90% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member, the position located on the downstream side with respect to the rotation direction of the second rotatable member is point Cd, and among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is 90% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member, the position located on the upstream side with respect to the rotation direction of the second rotatable member is point Du, and the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is point The position of the receiving magnetic pole located on the downstream side with respect to the rotation direction of the second rotatable member among the positions of the value of 90% of the maximum value of the magnetic flux density in the normal direction with respect to the outer peripheral surface of the second rotatable member is point Dd, the angle formed by the straight line L21C connecting the rotation center R2 and the point Cu and the straight line L22C connecting the rotation center R2 and the point Cd is Wc, and the angle formed by the straight line L21D connecting the rotation center R2 and the point Du and the straight line L22D connecting the rotation center R2 and the point Dd is Wd, the following relationship is satisfied: Wd / Wc ≥ 40%. , Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1is a schematic cross-sectional view of the image forming apparatus in the first embodiment. Figure 2 is a schematic cross-sectional view of a developing device according to the first embodiment. Figure 3 is a schematic diagram showing the arrangement of magnetic poles of the first developing roller in the first embodiment. Figure 4 is a schematic diagram showing the arrangement of magnetic poles of the second developing roller in the first embodiment. Figure 5 is a schematic diagram showing the arrangement of magnetic poles of the peeling roller in the first embodiment. Figure 6 1 is a schematic diagram showing the relationship of magnetic pole arrangements between the first developing roller and the second developing roller in the first embodiment. Figure 7 is a graph showing the magnetic characteristics of the second developing roller in the first embodiment. Figure 8 is a graph showing the magnetic characteristics at the periphery of the receiving magnetic pole of the second developing roller in the first embodiment. Fig. 9 1 is a schematic diagram for explaining the state of magnetic flux lines and magnetic flux density between the first developing roller and the second developing roller in the first embodiment. Fig.10 is a graph showing the magnetic characteristics of the second developing roller in the comparative example. Fig.11 is a graph showing magnetic characteristics at the periphery of the receiving magnetic pole of the second developing roller in the comparative example. Fig.12 : is a schematic diagram showing the state of magnetic flux lines and magnetic flux density between the first developing roller and the second developing roller in the comparative example. Fig.13 is a graph showing the magnetic characteristics of the second developing roller in the second embodiment. Fig.14 : is a schematic diagram showing the magnetic characteristics at the periphery of the transport magnetic pole of the second developing roller in the second embodiment. Fig.15 Shown in an enlarged manner Fig.14 A graph of the magnetic properties of the receiving magnetic pole. Fig.16 is a graph showing the magnetic characteristics at the periphery of the receiving magnetic pole of the second developing roller in the third embodiment. Fig.17 It is shown Fig.16 A graph of the magnetic properties of the receiving magnetic pole. Fig.18 is a graph showing in an enlarged manner the magnetic characteristics at the periphery of the receiving magnetic pole of the second developing roller in the fourth embodiment. Fig.19is a graph showing in an enlarged manner the magnetic characteristics at the periphery of the receiving magnetic pole of the second developing roller in the fifth embodiment. Fig. 20 is a graph showing the magnetic characteristics at the periphery of the transport magnetic pole of the first developing roller in the sixth embodiment. Fig.21 is a graph showing in an enlarged manner the magnetic characteristics of the transport magnetic pole under the first condition in another embodiment. Fig. 22 is a graph showing in an enlarged manner the magnetic characteristics of a transport magnetic pole in a first condition in another embodiment. DETAILED DESCRIPTION [First embodiment] Will use Figures 1 to 12 The first embodiment will be described. Figure 1 The overall structure of the image forming apparatus in this embodiment is described. [Imaging equipment] The image forming apparatus 100 is a full-color image forming apparatus, and in the case of the present embodiment, the image forming apparatus 100 is, for example, a multifunction peripheral (MFP) having a copy function, a printer function, and a scanner function. Figure 1 As shown, the image forming apparatus 100 includes image forming portions PY, PM, PC, and PK arranged in parallel for respectively performing image forming steps of forming toner images of four colors of yellow, magenta, cyan, and black. The image forming parts PY, PM, PC and PK for each color include primary chargers 21Y, 21M, 21C and 21K, developing devices 1Y, 1M, 1C and 1K, optical writing parts (exposure devices) 22Y, 22M, 22C and 22K, photosensitive drums 28Y, 28M, 28C and 28K, and cleaning devices 26Y, 26M, 26C and 26K, respectively. In addition, the image forming apparatus 100 also includes a transfer device 2 and a fixing device 3. Incidentally, the structures of the image forming parts PY, PM, PC and PK are similar to each other, so hereinafter, the image forming part PY will be described as a representative. The photosensitive drum 28Y as an image bearing member is a photosensitive member having a photosensitive layer including an organic photoconductor (OPC) formed of a resin such as polycarbonate, and is configured to rotate at a predetermined speed. The primary charger 21Y includes a corona discharge electrode provided at the periphery of the photosensitive drum 28Y and charges the surface of the photosensitive drum 28Y by the generated ions. In the optical writing part 22Y, a scanning optical device is installed, and by exposing the charged photosensitive drum 28Y according to the image data, the potential of the exposed part is lowered, so that a charge pattern (electrostatic latent image) corresponding to the image data is formed. The developing device 1Y develops the electrostatic latent image formed on the photosensitive drum 28Y by transferring the developer contained therein to the photosensitive drum 28Y. The developer is prepared by mixing the carrier with the toner of the relevant color, and the electrostatic latent image is visualized (developed) using the toner. The transfer device 2 includes primary transfer rollers 23Y, 23M, 23C, and 23K, an intermediate transfer belt 24, and a secondary transfer roller 25. The intermediate transfer belt 24 is wound around the primary transfer rollers 23Y, 23M, 23C, and 23K and a plurality of rollers and is supported to be travelable. The primary transfer rollers 23Y, 23M, 23C and 23K are pressed Figure 1 The secondary transfer roller 25 is disposed on the outer side of the intermediate transfer belt 24 and is configured so that the recording material can pass between the secondary transfer roller 25 and the intermediate transfer belt 24. Incidentally, the recording material is a sheet such as paper or a plastic sheet. The toner images of the respective colors formed on the photosensitive drums 28Y, 28M, 28C and 28K are sequentially transferred to the intermediate transfer belt 24 by the primary transfer rollers 23Y, 23M, 23C and 23K, respectively, so that a color toner image including superimposed layers of yellow, magenta, cyan and black is formed. The toner image thus formed is transferred by the secondary transfer roller 25 to the recording material fed from the box accommodating the recording material. The recording material to which the toner image is transferred is pressurized and heated in the fixing device 3. Thereby, the toner on the recording material is melted, so that the color image is fixed on the recording material. The developer storage portions 27Y, 27M, 27C, and 27K are provided corresponding to the developing devices 1Y, 1M, 1C, and 1K, respectively, in which bottles containing developers corresponding to yellow, magenta, cyan, and black are replaceably mounted in the order specified from top to bottom. The developer storage portions 27Y, 27M, 27C, and 27K are configured so that the developers can be fed (supplied) therefrom to the developing devices 1Y, 1M, 1C, and 1K, respectively, corresponding to the colors of the developers stored therein. For example, the toner weight ratio of the developer contained in each bottle is 80% to 95%, and the toner weight ratio of the developer of each of the developing devices 1Y, 1M, 1C, and 1K is 5% to 10%. Therefore, when the toner of each of the developing devices 1Y, 1M, 1C, and 1K is consumed due to development, the developer containing the toner amount corresponding to the toner consumption is supplied, so that the toner weight ratio of the developer of each of the developing devices 1Y, 1M, 1C, and 1K is kept constant. [Developing device] Next, we will use Figures 2 to 5 The developing devices 1Y, 1M, 1C, and 1K are described in detail. Incidentally, the structures of the developing devices 1Y, 1M, 1C, and 1K are the same, and therefore the developing device 1Y will be described as a representative hereinafter. Figure 2 Yes Description Figure 1 The conceptual diagram of the developing device 1Y shown in FIG. Figures 3 to 5 1Y is a conceptual diagram illustrating the magnetic pole structures of the first magnet 36 , the second magnet 37 , and the third magnet 38 , which are respectively provided inside the developing device 1Y. like Figure 2 As shown, the developing device 1Y includes a first developing roller 30 , a second developing roller 31 , a peeling roller 32 , a developer supplying screw 42 , a developer stirring screw 43 , and a developer collecting screw 44 , and these components are accommodated in a developing container 60 . The first developing roller 30 is a developer carrying member that is driven to rotate and is disposed at a position near the photosensitive drum 28Y so that its rotation axis is substantially parallel to the rotation axis of the photosensitive drum 28Y. The first developing roller 30 includes: a rotatable first sleeve 33; a first magnet (fixed magnet) 36 that is non-rotatably disposed inside the first sleeve 33 and is used to attract the developer to the surface of the first sleeve 33 by magnetic force. Then, the first developing roller 30 attracts (carries) the developer scooped from the developer supply screw 42 according to the magnetic force, and develops the electrostatic latent image formed on the rotating photosensitive drum 28Y (image bearing member) with the developer. The first sleeve 33 is a non-magnetic cylindrical member and is driven to rotate around the rotation axis 39. The rotation direction of the first sleeve 33 is as follows: Figure 2 The arrow in the middle indicates the clockwise direction and is the direction opposite to the rotation direction of the photosensitive drum 28. Therefore, the first sleeve 33 and the photosensitive drum 28Y rotate in the same direction at positions opposite to each other. That is, normal (positive) development is performed so that the photosensitive drum 28 rotates from bottom to top in the vertical direction at the position where the photosensitive drum 28 and the first sleeve 33 are opposite. The first magnet 36 is disposed inside the first sleeve 33 and Figure 3The figure shows a plurality of sector-shaped magnetic poles 101 to 107. A space is provided between the inner periphery of the first sleeve 33 and the outer periphery of the first magnet 36 to allow the first sleeve 33 to rotate. The developer attracted to the first sleeve 33 is conveyed toward the photosensitive drum 28Y by the rotation operation of the first sleeve 33, so that the electrostatic latent image formed on the photosensitive drum 28Y is developed with the developer. After the electrostatic latent image formed on the photosensitive drum 28Y is developed with the developer, the developer on the first sleeve 33 is conveyed to the vicinity of the second developing roller 31 by the rotation operation of the first sleeve 33. Then, in the vicinity of the closest position between the first developing roller 30 and the second developing roller 31, the developer is peeled off from the first sleeve 33 by the magnetic field generated by the first magnet 36 included in the first developing roller 30 and the second magnet 37 included in the second developing roller 31 and then conveyed to the surface of the second sleeve 34. The second developing roller 31 is a developer carrying member that is driven to rotate and is disposed downstream of the first developing roller 30 with respect to the rotation direction of the photosensitive drum 28Y, and the rotation center R2 of the second developing roller 31 is positioned above the rotation center R1 of the first developing roller 30 with respect to the vertical direction. The developer is conveyed from the first developing roller 30 to the second developing roller 31 by magnetic force ( Figure 2 In the present embodiment, the entire second developing roller 31 is positioned above the rotation center R1 of the first developing roller 30 . The second developing roller 31 is disposed at a position near the photosensitive drum 28Y similarly to the first developing roller 30 so that its rotation axis is substantially parallel to the rotation axis of the photosensitive drum 28Y. Therefore, the second developing roller 31 and the first developing roller 30 are substantially parallel in rotation axis. Such a second developing roller 31 includes a rotatable second sleeve 34, a second magnet (fixed magnet) 37 is non-rotatably provided in the second sleeve 34 and is used to attract the developer to the surface of the second sleeve 34 by magnetic force. Then, based on the magnetic force, the developer is transported from the first developing roller 30 (first sleeve 33) to the second developing roller 31, the second developing roller 31 attracts (carries) the developer, and the electrostatic latent image formed on the rotating photosensitive drum 28Y is developed with the developer. Incidentally, on one side of the second developing roller 31, a peeling roller 32 described later is positioned. The second sleeve 34 is a non-magnetic cylindrical member and is driven to rotate around the rotation axis 40. The rotation direction of the second sleeve 34 is similar to that of the first sleeve 33. Figure 2The arrow in the middle indicates the clockwise direction, and in this embodiment, it is opposite to the rotation direction of the photosensitive drum 28. Therefore, the second sleeve 34 and the photosensitive drum 28Y rotate in the same direction at positions opposite to each other. That is, conventional development is performed so that the photosensitive drum 28 rotates from bottom to top in the vertical direction at the position where the photosensitive drum 28 and the second sleeve 34 are opposite. In addition, the first sleeve 33 and the second sleeve 34 rotate in opposite directions at positions opposite to each other. The second magnet 37 is disposed inside the second sleeve 34 and Figure 4 The figure shows a plurality of sector-shaped magnetic poles 201 to 207. A space is provided between the inner periphery of the second sleeve 34 and the outer periphery of the second magnet 37 to allow the second sleeve 34 to rotate. The developer attracted to the second sleeve 34 is conveyed toward the photosensitive drum 28Y by the rotation operation of the second sleeve 34, so that the electrostatic latent image formed on the photosensitive drum 28Y is developed with the developer. After the electrostatic latent image formed on the photosensitive drum 28Y is developed with the developer, the developer remaining on the second sleeve 34 is conveyed to the vicinity of the peeling roller 32 by the rotation operation of the second sleeve 34. Then, in the vicinity of the closest position between the second developing roller 31 and the peeling roller 32, the developer is transported from the second sleeve 34 to the third sleeve 35 of the peeling roller 32 by the magnetic field generated by the second magnet 37 included in the second developing roller 31 and the third magnet 38 included in the peeling roller 32. The peeling roller 32 as a peeling portion is provided on the side opposite to the photosensitive drum 28Y with respect to the rotation center of the second sleeve 34, and peels off the developer from the second developing roller 31 after the electrostatic latent image on the photosensitive drum 28Y is developed by the second developing roller 31. Specifically, the peeling roller 32 is a developer carrying member that is rotationally driven, and is provided between the second developing roller 31 and the developer collecting screw 44 so that its rotation center is positioned above the rotation center R2 of the second developing roller 31. In addition, the peeling roller 32 is arranged so that its rotation axis is substantially parallel to the rotation axis of the second developing roller 31. Such a peeling roller 32 includes: a rotatable third sleeve 35; a third magnet (fixed magnet) 38, which is non-rotatably arranged in the third sleeve 35 and is used to attract the developer to the surface of the third sleeve 35 by magnetic force, and is configured so that the developer is transported from the second developing roller 31 to the third sleeve based on the magnetic force. The third sleeve 35 is a non-magnetic cylindrical member and is driven to rotate around the rotation axis 41. The rotation direction of the third sleeve 35 is as follows: Figure 2 The middle arrow indicates a counterclockwise direction and is a direction opposite to the rotation direction of the second sleeve 34. Therefore, the third sleeve 35 and the second sleeve 34 rotate in the same direction at positions opposite to each other. The third magnet 38 is disposed inside the third sleeve 35 and Figure 5 The third sleeve 35 includes a plurality of sector-shaped magnetic poles 301 to 305. Between the inner periphery of the third sleeve 35 and the outer periphery of the third magnet 38, a space is provided to allow the third sleeve 35 to rotate. The developer attracted to the third sleeve 35 is conveyed to the downstream side in the rotation direction by the rotation operation of the third sleeve 35, and is peeled off from the third sleeve 35 by the third magnet 38 included in the peeling roller 32 at a position close to the developer collecting screw 44, so that the developer falls toward the guide member 45 located below with respect to the vertical direction under the action of its own weight. Then, the developer dropped on the guide member 45 is guided toward the developer collecting screw 44 under the action of its own weight. The guide member 45 and the developer collecting screw 44 constitute a developer collecting portion 47 as a collecting portion for collecting the developer peeled off from the third sleeve 35 on the peeling roller 32. In the developer collecting portion 47, the developer collecting screw 44 is arranged so that its rotation center is positioned below the rotation center of the peeling roller 32 in the vertical direction, and conveys the developer delivered (collected) from the peeling roller 32 while stirring the developer. The guide member 45 as a guide portion is provided below the peeling roller 32 with respect to the vertical direction, and guides the developer peeled off by the peeling roller 32 toward the developer collecting screw 44. Such a guide member 45 is provided with an inclined surface 45a along which the developer slides downward under its own weight, thereby reliably guiding the peeled developer toward the developer collecting screw 44. The inclined surface 45a is inclined with respect to the horizontal direction so that its position on the developer collecting screw 44 side is lower than the lower position of the peeling roller 32. The developer collecting screw 44, which is a collecting member and a conveying (feeding) portion, conveys the collected developer to a developer circulation portion 46 described below. That is, the developer collecting screw 44 is a screw conveying (feeding) member for conveying the developer in one direction while stirring the developer collected by sliding downward along the inclined surface 45a of the guide member 45. The developer circulation portion 46 is a supply portion that supplies the developer to the first developing roller 30, and the developer circulation portion 46 includes a regulating member 50, a developer supply screw 42, and a developer stirring screw 43. In the developer circulation portion 46, the developer is supplied to the first developing roller 30 while being conveyed in a substantially horizontal direction while being stirred in the developer supply screw 42 and the developer stirring screw 43. In addition, as described above, the developer collected by the developer collecting portion 47 falls due to its own weight and is guided to the developer circulation portion 46. The developer supply screw 42, the developer stirring screw 43, and the developer collecting screw 44 are screw conveying members for conveying the developer in one direction while stirring the developer, and the developer supply screw 42 and the developer stirring screw 43 are positioned below the developer collecting screw 44 with respect to the vertical direction. In addition, the developer supply screw 42, the developer stirring screw 43, and the developer collecting screw 44 are arranged so that their rotation axes are substantially parallel to each other. The rotation axes of these screws are also substantially parallel to the rotation axis of the first developing roller 30. The developer supply screw 42 is positioned between the first developing roller 30 and the developer stirring screw 43, and is provided with a partition wall 48 of the developing container 60 between itself and the developer stirring screw 43. The partition wall 48 of the developing container 60 extends in the direction of the rotation axis of the developer supply screw 42 and the developer stirring screw 43. The partition wall 48 is provided with a communication opening (not shown) for establishing communication between a first feeding path 61 along which the developer supply screw 42 feeds the developer and a second feeding path 62 along which the developer stirring screw 43 feeds the developer. The developer stirred by the developer collecting screw 44 passes through a communication opening (not shown) formed in a partition wall 63 of the developer container 60 positioned between the developer collecting screw 44 and the developer supplying screw 42, and then falls due to its own weight toward the developer supplying screw 42. The above-mentioned guide member 45 is integrally formed with the partition wall 63 and the developer collecting screw 44 is provided above the partition wall 63. The position of the communication opening through which the developer stirred by the developer collecting screw 44 falls due to its own weight and is introduced into the developer circulation portion 46 may preferably be set to avoid the region (the middle portion with respect to the rotation axis direction of the developer supply screw 42) where the developer is supplied to the first developing roller 30, and is introduced into the developer circulation portion 46. In the present embodiment, the position of the communication opening is a position that is included in the range of the downstream end portion (terminal end portion) in the developer feeding direction with respect to the first feeding path 61 where the developer supply screw 42 is located. The developer feeding direction of the developer supply screw 42 and the developer feeding direction of the developer stirring screw 43 are opposite to each other. In addition, the starting end side (upstream end side in the developer feeding direction) and the terminal end side (downstream end side in the developer feeding direction) of the first feeding path 61 where the developer supply screw 42 is located and the terminal end side and the starting end side of the second feeding path 62 where the developer stirring screw 43 is located are connected to each other via the connecting openings provided in the partition wall 48. Therefore, the developer is connected to the developer container 60 by the developer supply screw 42 and the developer stirring screw 43. Figure 2 The developer circulates in the rotation direction indicated by the arrow in FIG. 3 and in the substantially horizontal direction, so that a portion of the developer is supplied to the first developing roller 30 . The developer supply opening 51 (see Figure 2 ) is disposed above the developer stirring screw 43 in the developing container 60 and is connected to the developer storage portion 27Y (see Figure 1 ). Further, the developer supply opening 51 is configured to be able to supply the developer contained in the bottle mounted in the developer storage portion 27Y into the second feeding path 62 where the developer stirring screw 43 is located. As described above, the toner weight ratio of the developer contained in the bottle of the developer storage portion 27Y is greater than the toner weight ratio of the developer in the developing device 1Y. Therefore, by adjusting the amount of developer supplied to the developer stirring screw 43, the toner weight ratio of the developer in the developing device 1Y can be maintained at a certain level. A toner concentration detection sensor 49 (see FIG. Figure 2 ) for detecting the toner concentration of the developer contained in the developer circulation part 46. The toner concentration detection sensor 49 is a sensor for detecting (magnetic) permeability. The toner concentration corresponds to the consumption of the toner in the developing device 1Y, and thus can be used to control the supply of the developer from the developer storage part 27Y. For example, when it is detected that the toner concentration is lower than a predetermined value, the developer is supplied from the developer storage part 27Y. Incidentally, the magnetic permeability changes as the toner concentration changes, and thus the toner concentration can be detected by utilizing the magnetic permeability. The regulating member 50 is disposed adjacent to the first developing roller 30 and is used to regulate the amount of developer supplied from the developer circulation portion 46 to the first developing roller 30. The regulating member 50 may be configured to regulate the amount of developer attracted to the first developing roller 30 according to a gap between the surface of the first sleeve 33 of the first developing roller 30 and an end portion of the regulating member 50. The circulation path of the developer in the developing container 60 is such that the developer is fed in a substantially horizontal direction while being stirred in the developer circulation portion 46, and then is supplied to the first developing roller 30, and then is conveyed from the first developing roller 30 to the second developing roller 31 positioned above the first developing roller 30 based on the magnetic force. Then, the developer is conveyed from the second developing roller 31 to the stripping roller 32 located beside the second developing roller 31 based on the magnetic force again, and then is stripped from the stripping roller 32 by the third magnet 38 included in the stripping roller 32. Further, the developer is collected by the developer collecting portion 47 and then introduced into the developer circulation portion 46 again. In addition, as described above, in this embodiment, a two-component development type is used as a development type, and a developer obtained by mixing a non-magnetic toner having a negative charge characteristic with a carrier having magnetism is used as a developer. The non-magnetic toner is a toner in which a colorant, a wax component, etc. are contained in a resin such as a polyester or a styrene acrylic resin, the mixture is made into a powder by pulverizing or polymerizing, and then a fine powder such as titanium oxide and silicon dioxide is added to the surface of the powder to obtain the toner. The magnetic carrier is a carrier obtained by coating a resin material on the core surface layer including ferrite particles or resin particles obtained by kneading with magnetic powder. In this embodiment, the toner concentration in the developer (the weight ratio of the toner to the developer) is 8% in the initial state. Generally speaking, the two-component development type using a colorant and a carrier has the characteristic that the stress applied to the colorant is smaller than the stress applied to the colorant of the single-component development type using a single-component developer. This is because the colorant and the carrier are charged to a predetermined polarity by making the colorant and the carrier in frictional electrical contact. On the other hand, due to long-term use, the amount of pollutants (waste materials) deposited on the surface of the carrier increases, so the charging ability of the colorant gradually decreases. Therefore, the problem of fogging and colorant scattering occurs. Although it is considered to increase the amount of carrier contained in the developing device in order to extend the service life of the two-component developing device, this will lead to an increase in the volume of the developing device, so it is not ideal. In order to solve the above-mentioned problem of the two-component developer, the ACR (Automatic Carrier Refresh) type is adopted in this embodiment. The ACR type is such a type that not only new developer is gradually supplied from the developer storage portion 27Y to the developing device 1Y, but also the developer with deteriorated charging performance is gradually discharged through the discharge port (not shown) of the developing device 1Y, thereby suppressing the increase in the amount of deteriorated developer. By this, the deteriorated carrier in the developing device 1Y is gradually replaced by a new carrier, so that the charging performance of the carrier in the developing device 1Y can be maintained at a substantially constant level. [Magnetic poles of a magnet] Next, the magnetic pole structures of the first magnet 36, the second magnet 37 and the third magnet 38 respectively included in the first developing roller 30, the second developing roller 31 and the peeling roller 32 will be described. Figure 3 , Figure 4 and Figure 5 shown. like Figure 3As shown, the first magnet 36 included in the first developing roller 30 has a 7-pole based magnetic pole structure including a plurality of magnetic poles 101, 102, 103, 104, 105, 106 and 107. Among these magnetic poles, the magnetic pole 106 is a conveying magnetic pole for conveying the developer from the first developing roller 30 to the second developing roller 31. The magnetic poles 101 to 107 are arranged in a specified order in the rotation direction of the first sleeve 33. In this embodiment, the magnetic flux densities of poles 101 to 107 are pole 101 = 290 Gauss, pole 102 = 770 Gauss, pole 103 = 1060 Gauss, pole 104 = 1640 Gauss, pole 105 = 870 Gauss, pole 106 = 360 Gauss and pole 107 = 450 Gauss. The magnetic pole 101 is an S pole and is disposed at a position opposing the regulating member 50 through the first sleeve 33, and regulates the amount of developer conveyed on the first sleeve 33 as described above. The magnetic pole 104 as a first conveying magnetic pole is an N pole and is disposed at a position opposing the photosensitive drum 28Y through the first sleeve 33, and is a magnetic pole for developing the electrostatic latent image formed on the photosensitive drum 28Y with the developer. Hereinafter, the magnetic pole 104 is referred to as a first developing magnetic pole 104 in some cases. The magnetic pole 106 as a transport magnetic pole is an N pole and is a magnetic pole used to transport the developer from the first sleeve 33 to the second sleeve 34 by generating a magnetic field in cooperation with the second magnet 37 of the second developing roller 31, and is hereinafter referred to as the transport magnetic pole 106 in some cases. The magnetic pole 107 is an N pole and is used to attract the developer supplied from the developer supply screw 42 to the first sleeve 33. The magnetic poles 102, 103 and 105 are respectively an N pole, an S pole and an N pole and serve as a feeding magnetic pole for feeding the developer attracted by the magnetic pole 107 upward as the first sleeve 33 rotates. Among these magnetic poles, the magnetic pole 105 is a first magnetic pole located upstream of the conveying magnetic pole 106 and adjacent to the conveying magnetic pole 106 with respect to the rotation direction of the first sleeve 33, and is hereinafter referred to as the first feeding magnetic pole 105 in some cases. The first developing magnetic pole 104 is located upstream of the first feeding magnetic pole 105 and adjacent to the first feeding magnetic pole 105 with respect to the rotation direction of the first sleeve 33. In addition, the magnetic pole 107 is arranged on the downstream side of the conveying magnetic pole 106 relative to the rotation direction of the first sleeve 33 and has the same polarity as the conveying magnetic pole 106. The conveying magnetic pole 106 and the magnetic pole 107 cooperate with each other to form a low magnetic force portion 110 whose magnetic force is lower than that of the conveying magnetic pole 106 through the repulsive magnetic field therebetween. Through the low magnetic force portion 110, the developer is peeled off from the first sleeve 33, and the conveyance of the developer from the first sleeve 33 to the second sleeve 34 is promoted. By the way, the low magnetic force portion 110 in this embodiment may have basically no magnetic force, but may have a lower magnetic force, for example, it may be a magnetic pole whose magnetic force (normal component Br of magnetic flux density) is less than 50 Gauss. The same applies to Figure 4 The low magnetic force portion 210 of the second magnet 37 is shown Figure 5 The low magnetic force portion 310 of the third magnet 38 is shown. like Figure 4 As shown, the second magnet 37 included in the second developing roller 31 has a structure based on 7 magnetic poles, which includes a plurality of magnetic poles 202, 203, 204, 205, 206 and 207. Among them, the magnetic pole 201 is a receiving magnetic pole for receiving the developer received by the second developing roller 31 from the first developing roller 30. The magnetic poles 201 to 207 are arranged in a specified order along the rotation direction of the second sleeve 34. The magnetic flux densities of the poles 201 to 207 in this embodiment are respectively pole 201 = 562 Gauss, pole 202 = 820 Gauss, pole 203 = 1560 Gauss, pole 204 = 870 Gauss, pole 205 = 720 Gauss, pole 206 = 690 Gauss and pole 207 = 280 Gauss. The magnetic pole 201 as a receiving magnetic pole is a magnetic pole for attracting the developer from the first sleeve 33 to the second sleeve 34 by the magnetic field generated by cooperating with the magnetic pole 106 of the first magnet 36 of the first developing roller 30. The magnetic pole 207 is a magnetic pole for conveying the developer from the second sleeve 34 to the third sleeve 35 by the magnetic field generated by cooperating with the third magnet 38 of the stripping roller 32. In addition, the magnetic pole 201 is an S pole having a polarity different from that of the conveying magnetic pole 106 and is used to attract the developer from the first developing roller 30 (first sleeve 33) to the second sleeve 34, as described above. The magnetic pole 203 as the second developing magnetic pole is an S pole, is a magnetic pole that is provided at a position opposite to the photosensitive drum 28Y through the second sleeve 34 and is used to develop the electrostatic latent image formed on the photosensitive drum 28Y. Hereinafter, the magnetic pole 203 is referred to as the second developing magnetic pole 203 in some cases. The magnetic poles 202, 204, 205, and 206 are N poles, N poles, S poles, and N poles and are used to feed the developer attracted by the magnetic pole 201 upward with the rotation of the second sleeve 34. Among these magnetic poles, the magnetic pole 202 is a second magnetic pole, which is positioned downstream of the receiving magnetic pole 201 and adjacent to the receiving magnetic pole 201 with respect to the rotation direction of the second sleeve 34, and is hereinafter referred to as the second feeding magnetic pole 202 in some cases. The second developing magnetic pole 203 is positioned downstream of the second feeding magnetic pole 202 with respect to the rotation direction of the second sleeve 34 and adjacent thereto. Magnetic pole 207 is an S pole, and after the developer passes through the developing area of ​​the photosensitive drum 28Y corresponding to the magnetic pole 203, the developer is transported from the second sleeve 34 to the third sleeve 35 opposite to the second sleeve 34 through the magnetic field generated by cooperating with the magnetic pole 303 in the third magnet 38 included in the peeling roller 32. In addition, the magnetic pole 207 is arranged on the upstream side of the receiving magnetic pole 201 with respect to the rotation direction of the second sleeve 34 and has the same polarity as the receiving magnetic pole 201. The receiving magnetic pole 201 and the magnetic pole 207 form a low magnetic force portion 210 having a lower magnetic force than the magnetic pole 207 by the repulsive magnetic field generated by the cooperation with each other. Through the low magnetic force portion 210, the developer is peeled off from the second sleeve 34, and the conveyance of the developer from the first sleeve 33 to the second sleeve 34 is promoted. In addition, through the low magnetic force portion 210, the developer can be prevented from being attracted to the closest portion between the first sleeve 33 and the second sleeve 34, and the pressure applied to the developer can be suppressed. like Figure 5 As shown, the third magnet 38 included in the peeling roller 32 is provided with a plurality of magnetic poles 301, 302, 303, 304, and 305. The magnetic poles 301 to 305 are arranged in a specified order in the rotation direction of the third sleeve 35. In this embodiment, the magnetic flux densities of the magnetic poles 301 to 305 are respectively 301 = 300 Gauss, 302 = 650 Gauss, 303 = 610 Gauss, 304 = 610 Gauss, and 305 = 540 Gauss. The magnetic pole 303 is an N pole having a different polarity from the magnetic pole 207 and is used to attract the developer stripped off from the second sleeve 34 as described above to the third sleeve 35. The magnetic poles 301, 302 and 304 are an N pole, an S pole and an S pole, and are used to feed the developer on the third sleeve 35 as the third sleeve 35 rotates. In particular, the magnetic pole 304 is used to feed downward the developer attracted by the magnetic pole 303 as the third sleeve 35 rotates. The magnetic pole 305 is an N pole and is a stripping magnetic pole for stripping the developer attracted to the third sleeve 35 from the third sleeve 35 by generating a repulsive magnetic field in cooperation with the magnetic pole 301 having the same polarity as the magnetic pole 305. [Magnetic pole arrangement relationship] Next, we will use Figures 6 to 9 The magnetic pole arrangement relationship between the first magnet 36 and the second magnet 37 respectively provided inside the first developing roller 30 and the second developing roller 31 is described. Figure 6 31 is a conceptual diagram for explaining the arrangement of the first developing roller 30 and the second developing roller 31 in this embodiment, and specifically shows the layout of the first feeding magnetic pole 105 and the conveying magnetic pole 106 of the first magnet 36 of the first developing roller 30 and the receiving magnetic pole 201 and the second feeding magnetic pole 202 of the second magnet 37 of the second developing roller 31. Incidentally, due to complexity, a part of the magnetic poles is omitted in the display. In addition, Figure 7 and Figure 8 are graphs each showing the magnetic characteristics of the second magnet 37 of the first developing roller 30 . Fig. 9 It is a conceptual diagram for illustrating the magnetic field of the first developing roller 30 and the second developing roller 31 of the present embodiment, and specifically illustrates the absolute values ​​of the magnetic flux density of the conveying pole 106, the first feeding pole 105, the receiving pole 201 and the second feeding pole 202, and the state of the magnetic flux lines (lines of magnetic flux) formed by these poles. In this embodiment, as described above, the developer in the developing device 1Y moves from the surface of the first sleeve 33 of the first developing roller 30 to the surface of the second sleeve 34 of the second developing roller 31 through the magnetic fields of both the conveying magnetic pole 106 in the first developing roller 30 and the receiving magnetic pole 201 in the second developing roller 31, and then moves to the surface of the third sleeve 35 of the peeling roller 32 after being used in the developing step of the electrostatic latent image on the photosensitive drum 28Y. The process of conveying the developer from the first sleeve 33 of the first developing roller 30 to the second sleeve 34 of the second developing roller 31 (arrow F1) will be described. Figure 6 and Fig. 9 As shown by the arrow F1 in FIG. 1 , the developer moves to the downstream side of the rotation direction 81 of the first sleeve 33 rotating around the rotation center R1 under the action of the magnetic force along the magnetic flux lines extending from the first feed magnetic pole 105 to the conveying magnetic pole 106 of the first magnet 36. Then, the developer moves from the first sleeve 33 to the second sleeve 34 under the action of the magnetic force along the magnetic flux lines extending from the conveying magnetic pole 106 to the receiving magnetic pole 201. Further, the developer moves to the downstream side of the rotation direction 82 of the second sleeve 34 rotating around the rotation center R2 under the action of the magnetic force along the magnetic flux lines extending from the receiving magnetic pole 201 to the second feed magnetic pole 202. Here, the position (peak position) of the maximum (value) (peak) of the normal component of the magnetic flux density of the receiving magnetic pole 201 on the surface of the second sleeve 34 is taken as point T ( Figure 8). Further, in the half-value position of the maximum value of the normal component of the magnetic flux density of the receiving magnetic pole 201, the upstream position relative to the rotation direction of the second sleeve 34 is taken as Hu, and the downstream position relative to the rotation direction of the second sleeve 34 is taken as Hd. In addition, Figure 6 and Figure 8 The definitions of the straight lines L1, L2, L3, L4, L20, L21 and L22 represented by dot-dash lines are as follows: L1: a horizontal line passing through the rotation center R1 of the first sleeve 33, L2: a horizontal line passing through the rotation center R2 of the second sleeve 34, L3: a vertical line passing through the rotation center R1 of the first sleeve 33, L4: A straight line passing through the rotation center R1 and the rotation center R2, L20: connects the rotation center R2 and point T (the peak position of the magnetic flux density of the receiving magnetic pole 201) Figure 8 ), L21: connects the rotation center R2 and point Hu (the upstream position of the half value of the peak value of the magnetic flux density of the receiving magnetic pole 201 with respect to the rotation direction 82 of the second sleeve 34) Figure 8 ) and L22: connects the rotation center R2 and point Hd (a downstream position of the half value of the peak value of the magnetic flux density of the receiving magnetic pole 201 with respect to the rotation direction 82 of the second sleeve 34) Figure 8 ) straight line. The developer is fed from the first feed magnetic pole 105 of the first sleeve 33 to the transport magnetic pole 106 under the action of the rotational force of the first sleeve 33 and the magnetic force along the magnetic flux density extending from the first feed magnetic pole to the transport magnetic pole 106. The peak value of the magnetic flux density of the transport magnetic pole 106 does not exceed the peak value (maximum value of the normal component) of the magnetic flux line of the receiving magnetic pole 201. In addition, the magnetic field (transport magnetic field) formed by the transport magnetic pole 106 and the receiving magnetic pole 201 and used to transport the developer from the first sleeve 33 to the second sleeve 34 is configured so that at the intersection P1 ( Figure 6 ) A repulsive force area is generated within the range of the upstream side of the rotation direction 81 of the first sleeve 33 and the peak position of the magnetic flux density of the first feed pole 105 (the maximum value position of the normal component on the surface of the first sleeve 33) relative to the downstream side of the rotation direction of the first sleeve, and the magnetic force polarity in the direction of the rotation center R1 near the outer peripheral surface of the first sleeve 33 becomes negative in the repulsive force area. The conveying magnetic field is configured so that at the intersection point P2 ( Figure 6) generates an attraction region within the range of the downstream side of the rotation direction 82 of the second sleeve 34 and the upstream side of the magnetic flux density peak position of the second feeding magnetic pole 202 relative to the rotation direction of the second sleeve, in which the magnetic force polarity in the direction of the rotation center R2 near the outer peripheral surface of the second sleeve 34 is positive. By this magnetic force relationship, the developer is transported from the first sleeve 33 to the second sleeve 34. Incidentally, the magnetic flux lines extending from the second feeding magnetic pole 202 are connected not only to the receiving magnetic pole 201 but also to the first feeding magnetic pole 105 of the first developing roller 30, which is composed of an S pole having a different polarity from the second feeding magnetic pole 202. Figure 6 As shown by the middle arrow F2, when the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is stronger than the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201 in terms of the magnetic force acting on the developer on the second sleeve 34 near the second feeding magnetic pole 202, the developer moves from the first feeding magnetic pole 105 to the second feeding magnetic pole 202 or from the second feeding magnetic pole 202 to the first feeding magnetic pole 105. In addition, the developer also contacts the photosensitive drum 28Y near these magnetic poles, so that a foggy image in the shape of vertical stripes is generated on the photosensitive drum 28Y. In order to suppress such movement of the developer in the direction of the arrow F2, it may be necessary to only weaken the magnetic field between the first feeding pole 105 and the second feeding pole 202 and to strengthen the magnetic field between the second feeding pole 202 and the receiving pole 201. As one method, a method of increasing the peak value of the magnetic flux density of the receiving pole 201 may be considered. However, when the peak value of the magnetic flux density of the receiving pole 201 increases, the force for restraining the developer near the closest position between the first sleeve 33 and the second sleeve 34 becomes larger, thereby applying pressure to the developer, so that the deterioration of the developer is accelerated. When the developer deteriorates, the charge amount of the colorant decreases, so that the electrostatic latent image on the photosensitive drum 28Y may not be developed with an appropriate amount of colorant. For the above reasons, it is not preferable to simply increase the peak value of the magnetic flux density of the receiving magnetic pole 201. In addition, the developer is transported between the transport magnetic pole 106 and the receiving magnetic pole 201, and therefore, the magnetic pole 107 having the same polarity and being a repelling magnetic pole is usually arranged downstream of the transport magnetic pole 106, and the magnetic pole 207 having the same polarity and being a repelling magnetic pole is arranged upstream of the receiving magnetic pole 201. Therefore, the half-value width of the transport magnetic pole 106 on the downstream side and the half-value width of the receiving magnetic pole 201 on the upstream side are easy to be widened. Therefore, the magnetic field acting between the transport magnetic pole 106 and the first feeding magnetic pole 105 and the magnetic field acting between the receiving magnetic pole 201 and the second feeding magnetic pole 202 become weak. If a magnetic pole having the same polarity and being a repelling magnetic pole is added on the downstream side of the transport magnetic pole 106 or the upstream side of the receiving magnetic pole 201 in order to narrow the half-value width, the developer on the relevant sleeve will move, so it is not preferable to set such a magnetic pole. Therefore, in this embodiment, the receiving magnetic pole 201 is arranged as follows. First, Figure 8 As shown, in the half-value width of the magnetic flux density peak of the receiving magnetic pole 201, the angle formed by the straight lines L20 and L21, which are the width of the upstream side of the magnetic flux density peak position of the receiving magnetic pole 201, is taken as angle wθ21, and the angle formed by the straight lines L20 and L21, which are the width of the downstream side of the magnetic flux density peak position of the receiving magnetic pole 201, is taken as wθ22. In addition, the angle difference (wθ22-wθ21) of the angle wθ21 relative to the angle wθ22 is Δwθ, that is, Δwθ=wθ22-wθ21. In this case, the receiving magnetic pole 201 is set to satisfy: Δwθ≥0. Thereby, the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is weakened, and the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201 is strengthened. In addition, the feeding performance of the developer from the first feeding magnetic pole 105 of the first sleeve 33 to the conveying magnetic pole 106 is also improved. Therefore, the movement of the developer between the first feeding magnetic pole 105 of the first developing roller 30 and the second feeding magnetic pole 202 of the second developing roller 31 can be suppressed. In this embodiment, the magnetic property distribution of the second magnet 37 is as follows: Figures 7 to 9 As shown in each figure. Figure 7 The graph shows Figure 3 and Figure 6 The positions of the magnetic poles 201 to 207 included in the second magnet 37 relative to the angular direction of the second sleeve 34 and the magnitude of the magnetic flux density in the normal direction are shown. Figure 7 In the figure, the abscissa represents the angle of the second magnet 37 relative to the rotation direction of the second sleeve 34 when the position of the photosensitive drum 28Y side relative to the horizontal line L2 on the rotation center R2 of the second developing roller 31 takes 0 degrees (in Figure 6 Indicated by arrows in the figure. Figure 7 In FIG. 1 , the ordinate represents the measurement result of the magnetic flux density of the second magnet 37 relative to the normal direction at the relevant angle of the second magnet 37 relative to the rotation direction. Figure 8 Shown in an enlarged manner Figure 7 The portion near the receiving magnetic pole 201 and the second feeding magnetic pole 202, wherein the straight lines L4 and L20 to L22 on the second sleeve 34 are represented by dot-dash lines, and the angles wθ21 and wθ22 are in the range of Figure 8 In the second magnet 37 of the present embodiment, the receiving magnetic pole 201 is set to provide an angle wθ21=12 degrees and an angle wθ22=15 degrees, so as to meet the requirement of the angle difference Δwθ=3 degrees. Here, the setting value adopted in the present embodiment is an example, and the above-mentioned angle difference Δw may only need to satisfy the relationship Δwθ≥0 and may preferably satisfy the relationship Δwθ>0. Fig. 9 1 is a schematic diagram showing arrow F1, the state of magnetic flux lines formed by the first feeding magnetic pole 105, the conveying magnetic pole 106, the receiving magnetic pole 201 and the second feeding magnetic pole 202, and the absolute value of the magnitude of the magnetic flux density of these magnetic poles in the normal direction, and arrow F1 represents the movement of the developer from the first feeding magnetic pole 105 on the first sleeve 33 to the second feeding magnetic pole 202 on the second sleeve 34. In this embodiment, the first feeding magnetic pole 105 and the receiving magnetic pole 201 are composed of S poles, and the conveying magnetic pole 106 and the second feeding magnetic pole 202 are composed of N poles. The magnetic poles connected to the first feeding magnetic pole 105 as the S pole through the magnetic flux lines are the conveying magnetic pole 106 and the second feeding magnetic pole 202 both as N poles. Here, as described above, the shape of the magnetic flux density of the receiving magnetic pole 201 is set so that the upstream angle wθ21 is the downstream angle 2θ22 or less in the half-value width of the magnetic flux density peak of the receiving magnetic pole 201 in the normal direction of the receiving magnetic pole 201. Therefore, in the half-value width of the magnetic flux density of the receiving magnetic pole 201 close to the first feeding magnetic pole 105, the downstream angle wθ22 is increased, so that the magnetic field between the first feeding magnetic pole 105 and the conveying magnetic pole 106 is enhanced, and the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is weakened. In addition, the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 as shown by the arrow F2 can be suppressed, so that the abnormal image (vertical stripe-like image) generated thereby can be suppressed. In addition, in order to weaken the magnetic field between the first feed pole 105 and the second feed pole 202, compared with simply increasing the peak value of the magnetic flux density of the receiving pole 201 in the normal direction of the receiving pole 201, by adopting a structure that only increases the downstream side angle of the half-width of the magnetic flux density of the receiving pole 201 close to the second feed pole 202 so that the angle difference Δwθ≥0, it is possible to suppress the increase in the force used to confine the developer near the closest position between the first sleeve 33 and the second sleeve 34, thereby suppressing the deterioration of the developer. Incidentally, in the second magnet 37, a portion of the magnet forming the receiving pole 201 relative to the circumferential direction is cut off, or a magnet with different magnetic force is embedded in the cut off portion, so that the magnetic flux density distribution of the receiving pole 201 can be asymmetric as described above. Next, we will use Figures 10 to 12 A comparative example to be compared with the present embodiment is described. In the comparative example, the magnetic characteristic distribution of the reception magnetic pole 201A is set so that the angle difference Δwθ satisfies Δwθ<0. Figures 10 to 12 The magnetic field state formed by the first feeding magnetic pole 105 , the transporting magnetic pole 106 , the receiving magnetic pole 201A, and the second feeding magnetic pole 202 in this comparative example is shown. Fig.10 The graph shown is a magnetic characteristic in a comparative example, showing that Figure 3 and Figure 6 The position of the magnetic poles included in the second magnet 37 disclosed in the figure relative to the angular direction and the magnitude of the magnetic flux density, and the curve diagram is the same as the above except for the receiving magnetic pole 201A. Figure 7 A graph similar to the graph of . Fig.11 is a curve graph in which the Fig.10 The receiving magnetic pole 201A and the position near the second feeding magnetic pole 202 are shown in the figure, wherein the straight lines L4 and L20 to L22 on the second sleeve 34 are indicated by dot-dash lines, and the sizes of the angles wθ21 and wθ22 are shown by double arrows. The receiving magnetic pole 201A of the second magnet 37 in the comparative example has the same peak value of the magnetic flux density as the receiving magnetic pole 201, and as a structure with a wider upstream width of Δwθ<0 at half-value width, the angles wθ21 and wθ22 are set to wθ21=12 degrees and wθ22=9 degrees. Fig.12 It is a schematic diagram showing arrow F1, the state of magnetic flux lines formed by the first feed pole 105, the transport pole 106A, the receiving pole 201A and the second feed pole 202, and the absolute value of the magnetic flux density of these poles in the normal direction. Arrow F1 shows the movement of the developer from the first feed pole 105 on the first sleeve 33 to the second feed pole 202 on the second sleeve 34. As described above, in the comparative example, the magnetic flux density shape of the receiving pole 201A is set so that the angle wθ22 is smaller than the angle wθ21. Therefore, in the structure where the angle wθ22 is narrower on the downstream side of the half-value width of the receiving pole 201A close to the second feed pole 202, the magnetic field between the second feed pole 202 and the receiving pole 201A is weak, and the magnetic field between the first feed pole 105 and the second feed pole 202 cannot be sufficiently weakened. Therefore, the developer moves between the first feed pole 105 and the second feed pole 202, so that the above-mentioned vertical stripe-shaped fog image appears. That is, the coating state of the developer on the second sleeve 34 is uneven, and an uneven image appears on the output image. On the other hand, in the present embodiment, the characteristics of the magnetic properties of the second magnet 37 are as follows: Figure 8 and Fig. 9 As shown, it is therefore possible to suppress the occurrence of unevenness and vertical stripe-shaped images in the output image in the comparative example. [experiment] Next, an experiment for checking the appearance of a streak-like fog image (abnormal image) in the above-mentioned structure will be described. In the example, the angle wθ21 and the angle wθ22 of the magnetic flux density distribution of the receiving magnetic pole 201 are changed, and an image is output through an imaging device in which a transport magnetic pole under various conditions is combined. Then, the appearance of a streak-like fog image on the output image is checked. In the experiment, the appearance of streak-like fog images on the output image is evaluated in the following way. A pure white image was formed on 10 A3 size sheets, and the number of vertical streaks on the output image was measured. In the case where there were no vertical streaks on the pure white images on 10 A3 size sheets, pure white images were formed on 100 A3 size sheets and then vertical streaks were checked. The results of this experiment are shown in Tables 1 and 2. Table 1 Table 2 *1: "AI" is an abnormal image The symbols in the abnormal image row in each of Tables 1 and 2 are evaluation results of the occurrence state of streak-like fog images (abnormal images), and the contents are as follows. ×: On one A3 size sheet, 10 or more vertical streaks were recognized. △: On one A3 size sheet, about one vertical stripe was recognized. ○: About one vertical streak was recognized on 10 A3 size sheets. In the above evaluation, "○" indicates a level at which abnormal images hardly occur in practice. The structures of the first developing roller 30 and the second developing roller 31 are as follows: Figure 6 As shown. The magnetic characteristics are such that the peak value of the magnetic flux density of the conveying magnetic pole 106 is fixed at 360 Gauss, the peak value of the magnetic flux density of the receiving magnetic pole 201 is fixed at 562 Gauss, and the shape of the magnetic flux density near the receiving magnetic pole 201 relative to the rotation angle of the second sleeve 34 is changed. As a method of changing the magnetic flux density, the magnetic flux density can be changed by changing the conditions when the receiving magnetic pole 201 carried by the second magnet 37 is magnetized or by cutting off a part of the magnet. By the way, the magnetic poles other than the receiving magnetic pole 201 are as follows Figures 7 to 10 shown. Table 1 shows the results when the angle wθ22 is increased from the state of angle wθ21 = 12 degrees and angle wθ22 = 9 degrees in the comparative example. In the case where the angle difference Δwθ between angle wθ21 and angle wθ22 is Δwθ<0, that is, in the case where angle wθ22 is smaller than angle wθ21, it is found that the appearance of abnormal images cannot be suppressed. This is because Fig.12 In the comparative example shown, the angle wθ22 adjacent to the second feeding magnetic pole 202 is small, and therefore, the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 cannot be sufficiently weakened by the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201, thereby causing the developer to move between the first feeding magnetic pole 105 and the second feeding magnetic pole 202. In addition, it can be said that since the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201 cannot be enhanced even when the angle wθ21 not adjacent to the second feeding magnetic pole 202 becomes large, the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 cannot be sufficiently weakened. On the other hand, in the case of Δwθ ≥ 0, that is, in the case where the angle wθ22 is not less than the angle wθ21, it is found that the occurrence of abnormal images can be suppressed. This is because as shown in reference Fig. 9 As described above, the angle wθ22 adjacent to the second feeding magnetic pole 202 is large, so the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201 becomes strong, thereby weakening the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202. Therefore, the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 in the direction of the arrow F2 can be suppressed, so that the occurrence of abnormal images can be suppressed. Table 2 shows the results of changing the conditions of the angle wθ22 in a structure in which the half-value width of the receiving magnetic pole 201 is narrower than that in Table 1. Similar to the results of Table 1, it is found that the occurrence of abnormal images can be suppressed by satisfying Δwθ≥0. However, in the conditions of Table 2, in the case of the angle difference Δwθ=0, the occurrence of abnormal images cannot be sufficiently suppressed compared with the results of Table 1. This is because the half-value width of the receiving magnetic pole 201 is 24 degrees when the angle difference Δw in Table 1 is Δwθ=0, and the half-value width of the receiving magnetic pole 201 is 16 degrees narrower than 24 degrees when the angle difference Δw in Table 2 is Δw=0. When the half-value width is narrow, the magnetic field between the receiving magnetic pole 201 and the second feeding magnetic pole 202 may change in a weakening direction in some cases due to the assembly tolerance of the first magnet 36 and the second magnet 37, some changes in the magnetic pole position affected by the magnetization change, and the like. In this case, the effect of weakening the magnetic field between the first feeding pole 105 and the second feeding pole 202 and suppressing the movement of the developer between the first feeding pole 105 and the second feeding pole 202 becomes small (weak). Therefore, in the case where the half value width is narrow, it is preferable to satisfy the angle difference Δwθ>0. As described above, according to the present embodiment, the occurrence of image defects can be suppressed. That is, in the developing device 1Y of the present embodiment, the developer is fed from the first feeding magnetic pole 105 to the conveying magnetic pole 106 on the first sleeve 33, and is conveyed to the second sleeve 34 according to the magnetic field between the conveying magnetic pole 106 and the receiving magnetic pole 201, and then is transferred from the receiving magnetic pole 201 to the second feeding magnetic pole 202 on the second sleeve 34. In this structure, in some cases, the developer moves from the first feeding magnetic pole 105 to the second feeding magnetic pole 202 along the magnetic field under the action of the magnetic force. On the other hand, in the present embodiment, the receiving magnetic pole 201 satisfies Δwθ≥0 as described above, and therefore, the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201 weakens the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202, so that the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed. Therefore, the occurrence of the above-mentioned streak-like fog image can be suppressed. In particular, even in an image forming apparatus having a high image forming speed (processing speed), movement of the developer between the first feed magnetic pole 105 and the second feed magnetic pole 202 can be suppressed, so that the occurrence of the above-mentioned streak-like fog image can be suppressed. In addition, the developer starts from the first developing roller 30 and then circulates stably through the second developing roller 31, the peeling roller 32 and the developer circulating portion 46, so that the developing device 1Y and the image forming apparatus that stably output images can be provided. Incidentally, the setting values ​​used in the present embodiment are examples, and as described above, the angle difference Δwθ may ideally satisfy Δwθ≥0°, preferably Δwθ≥3°, and more preferably Δwθ≥6°. This is because when the angle difference Δwθ becomes larger, the magnetic flux lines are more likely to extend between the receiving magnetic pole 201 and the second feeding magnetic pole 202, thereby producing an effect that the magnetic field acting between the receiving magnetic pole 201 and the second feeding magnetic pole 202 weakens the magnetic field acting between the first feeding magnetic pole 105 and the second feeding magnetic pole 202. <Second Embodiment> Will use Figures 13 to 15 A second embodiment is described. This embodiment is different from the first embodiment in the structure of the receiving magnetic pole 201B of the second magnet 37 of the second developing roller 31. The other structures and behaviors are similar to those of the first embodiment, and therefore, with regard to similar structures, descriptions and explanations are omitted or briefly explained by adding the same reference numerals or symbols, and hereinafter, the differences from the first embodiment will be mainly described. In the case of the first embodiment described above, if Figure 8 As shown, the relationship between the upstream half-width and the downstream half-width of the magnetic flux density of the receiving pole 201 of the second magnet 37 included in the second developing roller 31 relative to the rotation direction of the second sleeve 34 satisfies Δwθ≥0. The angle wθ22 close to the second feeding pole 202 is large, so the magnetic field between the second feeding pole 202 and the receiving pole 201 can weaken the magnetic field between the first feeding pole 105 and the second feeding pole 202. On the other hand, in this embodiment, if Fig.13 and Fig.14 As shown, in the position of the receiving magnetic pole 201 of the second magnet 37 used in the first embodiment, a receiving magnetic pole 201B is provided. The peak value of the magnetic flux density of the receiving magnetic pole 201B is the same as that of the receiving magnetic pole 201. On the other hand, the shape of the peak value of the magnetic flux density is changed to a flat shape. This flat shape will be described. Fig.15 1 shows the measurement result of the magnetic flux density of the receiving magnetic pole 201B in the normal direction of the receiving magnetic pole 201B, wherein the rotation direction of the second sleeve 34 is regarded as the abscissa. That is, Fig.15 : is a graph showing the normal component of the magnetic flux density of the receiving magnetic pole 201B on the surface of the second sleeve 34, wherein the ordinate represents the magnetic flux density and the abscissa represents the angle of the second sleeve 34 relative to the rotation direction of the second sleeve 34. Here, the values ​​Lt and Lh and the straight lines HLt, HLh, VL21 and VL22 are defined as follows: Lt: peak value of the magnetic flux density of the receiving magnetic pole 201B on the surface of the second sleeve 34 (maximum value of the normal component), Lh: half value of the peak value Lt of the magnetic flux density of the receiving magnetic pole 201B, HLt: A straight line (dashed line) parallel to the abscissa passing through the position of the value Lt, HLh: A straight line (dashed line) parallel to the abscissa passing through the position of the value Lh, VL21: a straight line (dash-dot line) parallel to the ordinate and passing through point Hu, and VL22: A straight line (dash-dot line) passing through point Hd and parallel to the ordinate. Incidentally, similarly to the first embodiment, Hu is a position on the upstream side of the half-value position of the maximum value of the normal component of the magnetic flux density of the receiving magnetic pole 201B with respect to the rotation direction of the second sleeve 34. Further, similarly to the first embodiment, Hd is a position on the downstream side of the half-value position of the normal component of the magnetic flux density of the receiving magnetic pole 201B with respect to the rotation direction of the second sleeve 34. Furthermore, the area of ​​the rectangle enclosed by the straight lines VL21, VL22, HLt and HLh is area S, and Fig.15 In the graph of , an area (shaded portion) obtained by integrating the normal component of the magnetic flux density of the receiving magnetic pole 201B from the straight line VL21 to the straight line VL22 at an angle relative to the rotation direction of the second sleeve 34 is the area Sa. As described above, in order to suppress the movement of the developer by weakening the magnetic field from the first feeding magnetic pole 105 to the second feeding magnetic pole 202, it is effective to enhance the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201B. Therefore, it is considered to make the peak value of the magnetic flux density of the receiving magnetic pole 201B larger, whereby the magnetic field between the receiving magnetic pole 201B and the second feeding magnetic pole 202 can be enhanced. However, the magnetic field that helps to transport the developer from the first sleeve 33 to the second sleeve 34 also changes greatly, so the enhanced magnetic field may cause the developer to move with the rotation of the first sleeve 33 and cause the developer to deteriorate. Therefore, in the present embodiment, the peak value of the magnetic flux density of the receiving magnetic pole 201B does not increase, but the area Sa which is the integral value of the value not less than the half value of the peak value of the magnetic flux density of the receiving magnetic pole 201B increases. Specifically, the portion of the receiving magnetic pole 201B near the peak value position of the magnetic flux density is formed into a flat shape so that the area ratio Sa / S of the area Sa to the area S reaches 75% or more (Sa / S≥75%). Therefore, the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201B is enhanced, and therefore, the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be weakened, so that the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed. Incidentally, the flat shape of the receiving magnetic pole 201B near the magnetic flux density peak is not limited to one peak, but may be multiple peaks, and may only be required to be constructed to satisfy the area ratio Sa / S ≥ 75%. Further, by cutting off a portion of the circumferential magnet of the second magnet 37 forming the receiving magnetic pole 201B or by embedding a magnet with a different magnetic force in the cut portion, a flat magnetic flux density distribution similar to that of the receiving magnetic pole 201B can be formed. In addition, the receiving magnetic pole 201B in the present embodiment adopts a flat shape of magnetic flux density in the normal direction, and the flat shape extends toward the downstream side and the upstream side of the magnetic flux density peak position in the normal direction of the receiving magnetic pole 201 in the first embodiment. Therefore, the range of the magnetic field formed between the conveying magnetic pole 106 and the receiving magnetic pole 201B is large, so that the influence of the magnetic field change of the conveying magnetic pole 106 and the receiving magnetic pole 201B caused by the magnetization change and assembly tolerance of the first magnet 36 and the second magnet 37 becomes small. That is, in the present embodiment, compared with the first embodiment, the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed with respect to the change of the magnetic pole arrangement of the first magnet 36 and the second magnet 37, while expanding the conveying latitude of the developer from the first sleeve 33 to the second sleeve 34. [experiment] Next, an experiment for checking the appearance of streak-like fog images (abnormal images) in the above-mentioned structure will be described. In this example, the area S and the area Sa are changed by adjusting the magnetic flux density of the receiving magnetic pole 201B, and an image is output by an imaging device combined with a transport magnetic pole under various conditions. Then, the appearance of streak-like fog images on the output image is checked. The other conditions and evaluations of this experiment are the same as those of the experiment described in the first embodiment. The experimental results are shown in Table 3. Table 3 *1: “Sa” represents area Sa [rad. Gauss]. *2: “S” represents area S [rad. Gauss]. *3: “AI” stands for abnormal image. The structures of the first developing roller 30 and the second developing roller 31 in the experiment are as follows: Figure 6 The magnetic properties are shown in Fig.15 As shown in FIG. 1 , the peak value of the magnetic flux density of the receiving magnetic pole 201B is fixed at 562 Gauss, and the shape of the magnetic flux density near the receiving magnetic pole 201B changes gradually from 60% to 80% according to the area ratio Sa / S. The magnetic poles other than the receiving magnetic pole 201B are as follows Fig.13 shown. As shown in Table 3, when the area ratio Sa / S is 75% or more, the occurrence of abnormal images can be suppressed. This has the effect of making the vicinity of the magnetic flux density peak of the receiving magnetic pole 201B close to the first feeding magnetic pole 105, so that the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201B is enhanced, while the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is weakened. On the other hand, when the area ratio Sa / S is less than 75%, the magnetic flux lines between the receiving magnetic pole 201B and the second feeding magnetic pole 202 are not easy to extend, so the effect of weakening the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is low, so that the developer moves between the first feeding magnetic pole 105 and the second feeding magnetic pole 202, and as a result, the abnormal images cannot be fully suppressed. As described above, according to the present embodiment, the occurrence of image defects can be suppressed. That is, in the developing device 1Y of the present embodiment, the developer is fed from the first feeding magnetic pole 105 to the conveying magnetic pole 106 on the first sleeve 33, and is conveyed to the second sleeve 34 based on the magnetic field from the conveying magnetic pole 106 to the receiving magnetic pole 201B, and then is transferred from the receiving magnetic pole 201B to the second feeding magnetic pole 202 on the second sleeve 34. In such a structure, in some cases, the developer moves from the first feeding magnetic pole 105 to the second feeding magnetic pole 202 along the magnetic field under the action of the magnetic force. On the other hand, in the present embodiment, the vicinity of the peak value of the magnetic flux density is configured to have a flat shape so that the receiving magnetic pole 201B satisfies the area ratio Sa / S≥75% as described above, so that the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201B weakens the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202, and thus the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed. Therefore, the occurrence of the above-mentioned streak-like fog image can be suppressed. Incidentally, the setting values ​​adopted in the present embodiment are examples, and as described above, the magnetic flux density distribution of the receiving magnetic pole 201B can ideally satisfy the area ratio Sa / S ≥ 75%, preferably Sa / S ≥ 78%, and more preferably Sa / S ≥ 80%. This is because when the area ratio becomes larger, the magnetic flux lines are more likely to extend between the receiving magnetic pole 201B and the second feeding magnetic pole 202, thereby producing an effect that the magnetic field acting between the receiving magnetic pole 201B and the second feeding magnetic pole 202 weakens the magnetic field acting between the first feeding magnetic pole 105 and the second feeding magnetic pole 202. <Third Embodiment> Will use Fig.16 and Fig.17A third embodiment is described. This embodiment is different from the first embodiment in the structure of the receiving magnetic pole 201C of the second magnet 37 of the second developing roller 31. The other structures and behaviors are similar to those of the first embodiment, and therefore, for similar structures, descriptions and explanations are omitted or briefly explained by adding the same reference numerals or symbols, and hereinafter, the differences from the first embodiment will be mainly described. In the case of the second embodiment described above, if Fig.15 As shown, the integral value Sa of the receiving pole 201B of the second magnet 37 included in the second developing roller 31, which is not less than half the value of the peak value of the magnetic flux density, increases, so that the area ratio Sa / S becomes 75% or greater, thereby enhancing the magnetic field between the second feed pole 202 and the receiving pole 201B, and weakening the magnetic field between the first feed pole 105 and the second feed pole 202. On the other hand, in this embodiment, if Fig.16 As shown, a receiving magnetic pole 201C is provided in the position of the receiving magnetic pole 201 of the second magnet 37 used in the first embodiment. The peak value of the magnetic flux density of the receiving magnetic pole 201C is the same as that of the receiving magnetic pole 201. On the other hand, the shape of the peak value of the magnetic flux density is close to a flat shape. This flat shape will be described. Fig.17 The measurement result of the magnetic flux density of the receiving magnetic pole 201C in the normal direction of the receiving magnetic pole 201 is shown, wherein the rotation direction of the second sleeve 34 is regarded as the abscissa. Here, as described below, the values ​​C and D, the points Cd, Cu, Dd and Du, the straight lines L21C, L22C, L21D and L22D, and the angles Wc and Wd are defined. Incidentally, similar to the second embodiment, the value Lt is the peak value of the magnetic flux density of the receiving magnetic pole 201C. C: 10% of the value Lt, D: 90% of the value Lt, Cu: the upstream side position with respect to the rotation direction of the second sleeve 34 among the positions where the normal component of the magnetic flux density of the receiving magnetic pole 201C becomes the value C, Cd: the upstream position with respect to the rotation direction of the second sleeve 34 among the positions where the normal component of the magnetic flux density of the receiving magnetic pole 201C becomes the value C, Du: the upstream position with respect to the rotation direction of the second sleeve 34 among the positions where the normal component of the magnetic flux density of the receiving magnetic pole 201C becomes the value D, Dd: a position on the downstream side with respect to the rotation direction of the second sleeve 34 among the positions where the normal component of the magnetic flux density of the receiving magnetic pole 201C becomes a value of D, L21C: a straight line (dash-dot line) connecting the rotation center R2 of the second sleeve 34 and point Cu, L22C: A straight line (dash-dot line) connecting the rotation center R2 and point Cd. L21D: The straight line (dash-dot line) connecting the rotation center R2 and point Du. L22D: A straight line (dash-dot line) connecting the rotation center R2 and point Dd. Wc: the angle formed by the line L21C and the line L22C, and Wd: Angle formed by straight line L21D and straight line L22D. As described above, in order to suppress the movement of the developer between the first feed pole 105 and the second feed pole 202 by weakening the magnetic field from the first feed pole 105 to the second feed pole 202, it is effective to enhance the magnetic field between the second feed pole 202 and the receiving pole 201C. Therefore, it is considered that the peak value of the magnetic flux density of the receiving pole 201C is made larger, thereby enhancing the magnetic field between the receiving pole 201C and the second feed pole 202. However, the magnetic field that helps to transport the developer from the first sleeve 33 to the second sleeve 34 also changes greatly, and therefore, the enhancement of the magnetic field may cause the developer to move with the rotation of the first sleeve 33 and cause the developer to deteriorate. Therefore, in the present embodiment, the peak value of the magnetic flux density of the receiving magnetic pole 201C is not large, but the angle Wd, which is the width of 90% value of the peak value of the magnetic flux density of the conveying magnetic pole 106C, is large. Specifically, the portion of the receiving magnetic pole 201C near the peak position of the magnetic flux density is formed into a flat shape, so that the angle ratio Wd / Wc of the angle Wd to the angle Wc becomes 40% or more (Wd / Wc≥40%), and the angle Wc is the width of 10% value of the peak value of the magnetic flux density of the receiving magnetic pole 201C. Therefore, the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201C is enhanced, so that the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be weakened, so that the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed. Incidentally, the flat shape of the receiving magnetic pole 201C near the magnetic flux density peak is not limited to one peak, but may be a plurality of peaks, and may only be required to be configured to satisfy the angle ratio Wd / Wc ≥ 40%. In addition, the flat magnetic flux density distribution in the receiving magnetic pole 201C may be formed by cutting off a portion of the circumferential magnet of the second magnet 37 forming the receiving magnetic pole 201C or by embedding a magnet having a different magnetic force in the cut portion. In addition, the receiving magnetic pole 201C in the present embodiment adopts a flat shape of magnetic flux density in the normal direction, and the flat direction extends to the downstream and upstream sides of the peak position of the magnetic flux density of the receiving magnetic pole 201 in the normal direction in the first embodiment. Therefore, the magnetic field range between the receiving magnetic pole 201C and the receiving magnetic pole 201 is wide, so that the influence of the magnetic field change of the conveying magnetic pole 106 and the receiving magnetic pole 201C caused by the magnetization change of the first magnet 36 and the second magnet 37 and the assembly tolerance becomes small. That is, in the present embodiment, compared with the first embodiment, the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed with respect to the change of the magnetic pole arrangement of the first magnet 36 and the second magnet 37, while expanding the conveying latitude of the developer from the first sleeve 33 to the second sleeve 34. [experiment] Next, an experiment for checking the appearance of a streak-like fog image (abnormal image) in the above-mentioned structure will be described. In this example, the angle Wc and the angle Wd are changed by adjusting the magnetic flux density of the receiving magnetic pole 201C, and an image is output by an imaging device combined with a transport magnetic pole under various conditions. Then, the appearance of a streak-like fog image on the output image is checked. The other conditions and evaluations of this experiment are the same as those of the experiment described in the first embodiment. The experimental results are shown in Table 4. Table 4 *1: “AI” is an abnormal image. The structures of the first developing roller 30 and the second developing roller 31 in the experiment are as follows: Figure 6 The magnetic properties are shown in Fig.16 As shown, the peak value of the magnetic flux density of the receiving magnetic pole 201C is fixed at 562 Gauss, and the magnetic flux density shape of the receiving magnetic pole 201C changes step by step from 22% to 51% according to the angle ratio Wd / Wc. Fig.13 shown. As is clear from Table 4, when the angle ratio Wd / Wc is 40% or more, the occurrence of abnormal images can be suppressed. This has the effect of bringing the vicinity of the peak value of the magnetic flux density of the receiving pole 201C close to the second feeding pole 202, thereby strengthening the magnetic field between the second feeding pole 202 and the receiving pole 201C and weakening the magnetic field between the first feeding pole 105 and the second feeding pole 202. On the other hand, when the angle ratio Wd / Wc is less than 40%, the effect of the magnetic flux of the receiving pole 201C weakening the magnetic field between the first feeding pole 105 and the second feeding pole 202 is low, causing the developer to move between the first feeding pole 105 and the second feeding pole 202, with the result that the abnormal images cannot be sufficiently suppressed. As described above, according to the present embodiment, the occurrence of image defects can be suppressed. That is, in the developing device 1Y of the present embodiment, the developer is fed from the first feeding magnetic pole 105 to the conveying magnetic pole 106 on the first sleeve 33, and is conveyed to the second sleeve 34 based on the magnetic field between the conveying magnetic pole 106 and the receiving magnetic pole 201C, and then is transferred from the receiving magnetic pole 201C to the second feeding magnetic pole 202 on the second sleeve 34. In such a structure, in some cases, the developer moves along the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 under the action of the magnetic force. On the other hand, in the present embodiment, the vicinity of the peak value of the magnetic flux density is configured in a flat shape so that the receiving magnetic pole 201C satisfies the angle ratio Wd / Wc≥40% as described above, so that the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201C weakens the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202, and thus the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed. For this reason, the occurrence of the above-mentioned streak-like fog image can be suppressed. Incidentally, the setting values ​​adopted in the present embodiment are examples, and as described above, the magnetic flux density distribution of the receiving magnetic pole 201C can ideally satisfy the angle ratio Wd / Wc≥40%, preferably Wd / Wc≥43%, and more preferably Wd / Wc≥45%. This is because when the angle ratio becomes larger, the magnetic flux lines are more likely to extend between the receiving magnetic pole 201C and the second feeding magnetic pole 202, thereby producing an effect that the magnetic field acting between the receiving magnetic pole 201C and the second feeding magnetic pole 202 weakens the magnetic field acting between the first feeding magnetic pole 105 and the second feeding magnetic pole 202. <Fourth Embodiment> Will use Fig.18 A fourth embodiment is described. This embodiment is different from the first embodiment in the structure of the receiving magnetic pole 201D of the second magnet 37 of the second developing roller 31. The other structures and behaviors are similar to those of the first embodiment, so for similar structures, the description and explanation are omitted or briefly explained by adding the same reference numerals or symbols, and hereinafter, the differences from the first embodiment will be mainly described. In this embodiment, if Fig.18As shown, a receiving pole 201D is provided at the position of the receiving pole 201 of the second magnet 37 adopted in the first embodiment. The peak value of the magnetic flux density of the receiving pole 201D is the same as the peak value of the magnetic flux density of the receiving pole 201. On the other hand, the present embodiment is characterized in that the shape of the peak value of the magnetic flux density of the receiving pole 201D is a shape close to a flat shape, and in the half value, the downstream side width is wider than the upstream side width. Specifically, a structure is provided that satisfies the angle difference Δwθ≥0 described in the first embodiment and the area ratio Sa / S≥70% described in the second embodiment. Incidentally, in the case of the present embodiment, unlike the second embodiment, Δwθ2≥0 is satisfied, and therefore, with respect to the area ratio Sa / S, it may only be required to satisfy Sa / S≥65%. However, it is preferable to satisfy Sa / Sa≥70%. In this case of the present embodiment, the magnetic flux density of the receiving magnetic pole 201D on the downstream side of the magnetic flux density peak of the receiving magnetic pole 201D is greater than the magnetic flux density of the transporting magnetic pole in the same range in the first and second embodiments in the range near the second feeding magnetic pole 202. Therefore, the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201D is stronger than in the first and second embodiments, and the effect of weakening the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is higher. Therefore, the effect of suppressing the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 becomes higher. <Experiment> Next, an experiment for checking the appearance state of a streak-like fog image (abnormal image) in the above-mentioned structure will be described. In this example, the angle difference Δwθ and the area ratio Sa / S are changed by adjusting the magnetic flux density of the receiving magnetic pole 201D, and an image is output by an imaging device combined with a transport magnetic pole under various conditions. Then, the appearance state of a streak-like fog image on the output image is checked. The other conditions and evaluations of the experiment were the same as those described in the first embodiment. Figure 5 The results of this experiment are shown in . Table 5 *1: “AI” is an abnormal image The structures of the first developing roller 30 and the second developing roller 31 in the experiment are as follows: Figure 6 The magnetic characteristics make the peak value of the magnetic flux density of the receiving magnetic pole 201D fixed at 562 Gauss, the angle difference Δwθ changes from -3 (°) to 3 (°), and at the same time, the shape of the magnetic flux density of the receiving magnetic pole 201D changes from 61% to 75% according to the area ratio Sa / S. The magnetic poles other than the receiving magnetic pole 201D are as follows Figure 7 shown. As is clear from Table 5, when the angle difference Δwθ is 0 (°) or more and the area ratio Sa / S is 70% or more, the occurrence of abnormal images can be suppressed. The effect is that the vicinity of the peak value of the magnetic flux density of the receiving magnetic pole 201D is close to the second feeding magnetic pole 202, so the magnetic field between the first feeding magnetic pole 105 and the receiving magnetic pole 201D is enhanced, and the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is weakened. In addition, even in the case of the angle difference Δwθ=-1(°) and the area ratio Sa / S=65%, the effect of suppressing the occurrence of abnormal images was confirmed. However, under this condition, due to the assembly tolerance of the first magnet 36 and the second magnet 37 and the influence of the magnetization change, the magnetic pole position changes slightly, so that the magnetic field between the receiving pole 201D and the second feed pole 202 changes in the weakening direction, so that in some cases, the weakening effect of the magnetic field between the first feed pole 105 and the second feed pole 202 becomes lower. Therefore, it is preferable to satisfy Δwθ≥0, in which case, it may only be necessary to satisfy Sa / S≥65%. However, it is more preferable to satisfy the angle difference Δwθ≥0 and the area ratio Sa / S≥70%. As described above, according to the present embodiment, the occurrence of image defects can be suppressed. That is, in the developing device 1Y of the present embodiment, the developer is fed from the first feeding magnetic pole 105 to the conveying magnetic pole 106 on the first sleeve 33, and is conveyed to the second sleeve 34 based on the magnetic field between the conveying magnetic pole 106 and the receiving magnetic pole 201D, and then is conveyed from the receiving magnetic pole 201D to the second feeding magnetic pole 202 on the second sleeve 34. In this structure, in some cases, the developer moves along the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 under the action of the magnetic force. On the other hand, in the present embodiment, the magnetic flux density of the receiving magnetic pole 201D satisfies the angle difference Δwθ ≥ 0 and the area ratio Sa / S ≥ 65%, preferably the area ratio Sa / S ≥ 70% as described above, so that the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201D weakens the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202, and thus the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed. Therefore, the occurrence of the above-mentioned streak-like fog image can be suppressed. <Fifth Embodiment> Will use Fig.19 A fifth embodiment is described. This embodiment is different from the first embodiment in the structure of the receiving magnetic pole 201E of the second magnet 37 of the first developing roller 30. The other structures and behaviors are similar to those of the first embodiment, so for similar structures, the description and explanation are omitted or briefly explained by adding the same reference numerals or symbols, and hereinafter, the differences from the first embodiment will be mainly described. In this embodiment, if Fig.19As shown, at the position of the receiving pole 201 of the second magnet 37 adopted in the first embodiment, a receiving pole 201E is provided. The peak value of the magnetic flux density of the receiving pole 201E is the same as the peak value of the magnetic flux density of the receiving pole 201. On the other hand, the characteristic of the present embodiment is that the shape of the peak value of the magnetic flux density of the receiving pole 201E is close to a flat shape, and at half value, the downstream side width is wider than the upstream side width. Specifically, a structure is provided that satisfies the angle difference Δwθ≥0 described in the first embodiment and the angle ratio Wd / Wc≥35% described in the third embodiment. Incidentally, in the case of the present embodiment, unlike the third embodiment, Δwθ≥0 is satisfied, and therefore, with respect to the angle ratio Wd / Wc, it may only be necessary to satisfy Wd / Wc≥30%. However, it is preferable to satisfy Wd / Wc≥35%. In this case of the present embodiment, the magnetic flux density of the receiving magnetic pole 201E on the downstream side of the peak value of the magnetic flux density of the receiving magnetic pole 201E in the range close to the second feeding magnetic pole 202 is greater than the magnetic flux density of the transporting magnetic pole in the same range in the first and third embodiments. Therefore, the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201E is stronger, and the effect of weakening the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is higher than in the first and third embodiments. Therefore, the effect of suppressing the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 becomes higher. <Experiment> Next, an experiment for checking the appearance of a streak-like fog image (abnormal image) in the above-mentioned structure will be described. In this example, the angle difference Δwθ and the angle ratio Wd / Wc are changed by adjusting the magnetic flux density of the receiving magnetic pole 201E, and an image is output by an imaging device combined with a conveying magnetic pole under various conditions. Then, the appearance of a streak-like fog image on the output image is checked. The other conditions and evaluations of this experiment are the same as those of the experiment described in Example 1. The results of this experiment are shown in Table 6. Table 6 *1: “AI” is an abnormal image The structures of the first developing roller 30 and the second developing roller 31 in the experiment are as follows: Figure 6 As shown in the figure, the magnetic characteristics make the peak value of the magnetic flux density of the receiving magnetic pole 201E fixed at 562 Gauss, and the angle difference Δwθ changes from -3 (°) to 3 (°). At the same time, the magnetic flux density shape of the receiving magnetic pole 201E gradually changes from 25% to 46% according to the angle ratio Wd / Wc. The magnetic poles other than the receiving magnetic pole 201E are as follows Figure 7 shown. As is clear from Table 6, when the angle difference Δwθ is 0 (°) or more and the angle ratio Wd / Wc is 35% or more, the occurrence of abnormal images can be suppressed. The effect is that the vicinity of the peak value of the magnetic flux density of the receiving magnetic pole 201E is close to the second feeding magnetic pole 202, so the magnetic field between the second feeding magnetic pole 202 and the receiving magnetic pole 201E is enhanced, while the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 is weakened. In addition, even in the case of the angle difference Δwθ=-1(°) and the angle ratio Wd / Wc=30%, the effect of suppressing the occurrence of abnormal images was confirmed. However, under this condition, due to the influence of the assembly tolerance of the first magnet 36 and the second magnet 37 and the magnetization change, the magnetic pole position changes slightly, causing the magnetic field between the receiving pole 201E and the second feed pole 202 to change in the weakening direction, so that in some cases, the weakening effect of the magnetic field between the first feed pole 105 and the second feed pole 202 becomes lower. Therefore, it is preferable to satisfy Δwθ≥0, in which case it may only be necessary to satisfy Wd / Wc≥30%. However, it is more preferable to satisfy the angle difference Δwθ≥0 and the angle ratio Wd / Wc≥35%. As described above, according to the present embodiment, the occurrence of image defects can be suppressed. That is, in the developing device 1Y of the present embodiment, the developer is fed from the first feeding magnetic pole 105 to the conveying magnetic pole 106 on the first sleeve 33, and is conveyed to the second sleeve 34 based on the magnetic field between the conveying magnetic pole 106 and the receiving magnetic pole 201E, and then is conveyed from the receiving magnetic pole 201E to the second feeding magnetic pole 202 on the second sleeve 34. In this structure, in some cases, the developer moves along the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 under the action of the magnetic force. On the other hand, in the present embodiment, the magnetic flux density of the receiving magnetic pole 201E satisfies the angle difference Δw ≥ 0 and the area ratio Wd / Wc ≥ 30%, preferably the above-mentioned angle ratio Sa / S ≥ 35%, so that the magnetic field between the first feeding magnetic pole 105 and the receiving magnetic pole 201E weakens the magnetic field between the first feeding magnetic pole 105 and the second feeding magnetic pole 202, thereby suppressing the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202. Therefore, the appearance of the above-mentioned streak-like fog image can be suppressed. <Sixth Embodiment> Will use Fig. 20 A sixth embodiment is described. This embodiment is different from the first embodiment in the structure of the first magnetic pole 106A of the first magnet 36 of the first developing roller 30. The other structures and behaviors are similar to those of the first embodiment, and therefore, for similar structures, descriptions and explanations are omitted or briefly explained by adding the same reference numerals or symbols, and hereinafter, the differences from the first embodiment will be mainly described. Here, the position (peak position) of the maximum value (value) (peak value) of the normal component of the magnetic flux density of the conveying magnetic pole 106A on the surface of the first sleeve 33 is taken as point T. In addition, in the half-value position of the maximum value of the normal component of the magnetic flux density of the conveying magnetic pole 106A, the downstream side position relative to the rotation direction of the first sleeve 33 is taken as Hd', and the upstream side position relative to the rotation direction of the first sleeve 33 is taken as Hu'. In addition, Fig. 20 The definitions of the straight lines L1, L3, L4, L10, L11 and L12 represented by dot-dash lines are as follows: L1: a horizontal line passing through the rotation center R1 of the first sleeve 33, L3: a vertical line passing through the rotation center R1 of the first sleeve 33, L4: A straight line passing through the rotation center R1 and the rotation center R2, L10: a straight line connecting the portion R1 and the point T' (the peak position of the magnetic flux density of the transport magnetic pole 106A), L11: a straight line connecting the rotation center R1 and the point Hd′ (a position on the downstream side of the half value of the peak value of the magnetic flux density of the conveying magnetic pole 106A with respect to the rotation direction 81 of the first sleeve 33), and L12: A straight line connecting the rotation center R1 and the point Hu′ (a position on the upstream side of the half value of the peak value of the magnetic flux density of the transport magnetic pole 106A with respect to the rotation direction 81 of the first sleeve 33). In this embodiment, if Fig. 20 As shown, at the position of the transport magnetic pole 106 of the first magnet 36 used in Example 1, a transport magnetic pole 106A is arranged. The peak value of the magnetic flux density of the transport magnetic pole 106A is the same as the peak value of the magnetic flux density of the transport magnetic pole 106. On the other hand, in the half-value width of the magnetic flux density peak of the transport magnetic pole 106A, the angle formed by the straight lines L10 and L12 (that is, the half-value width on the upstream side of the magnetic flux density peak position of the transport magnetic pole 106A) is taken as angle wθ11, and the angle formed by the straight lines 10 and 11 (that is, the half-value width on the downstream side of the magnetic flux density peak position of the transport magnetic pole 106A) is taken as angle wθ12. In addition, the angle difference (wθ11-wθ12) of the angle wθ12 relative to the angle wθ11 is taken as the angle difference Δwθ1', that is, Δwθ'=wθ11-wθ12. In this case, the transport magnetic pole 106A is set to satisfy Δwθ'≥0. That is, in this embodiment, the angle differences Δwθ≥0 and Δwθ′≥0 described in Embodiment 1 are satisfied. In this case of the present embodiment, compared with the first embodiment, the upstream side magnetic flux value is larger than the peak value of the magnetic flux density of the transport magnetic pole 106 near the first feed magnetic pole 105. Therefore, the magnetic field acting between the transport magnetic pole 106A and the first feed magnetic pole 105 is stronger than that in the first embodiment, so that the effect of weakening the magnetic field between the first feed magnetic pole 105 and the second feed magnetic pole 202 is greater. Therefore, the effect of preventing the developer from moving between the first feed magnetic pole 105 and the second feed magnetic pole 202 becomes greater. <Experiment> Next, an experiment for checking the appearance state of a streak-like fog image (abnormal image) in the above-mentioned structure will be described. In this example, the angle difference Δwθ and the angle difference Δwθ' are changed by adjusting the magnetic flux density of the conveying magnetic pole 106A and the receiving magnetic pole 201, and an image is output by an imaging device incorporating the conveying magnetic poles under various conditions. Then, the appearance state of a streak-like fog image on the output image is checked. The other conditions and evaluations of the experiment were the same as those of the experiment described in the first embodiment, but the following evaluation criteria were added in this experiment. ◎: About one vertical streak was recognized on 10,000 A3-size sheets.

[0182] The results of this experiment are shown in Table 4. Table 7 *1: “AI” is an abnormal image The structures of the first developing roller 30 and the second developing roller 31 in the experiment are as follows: Figure 6 As shown. The peak value of the magnetic flux density of the transporting magnetic pole 106A is fixed to 360 Gauss, and the peak value of the magnetic flux density of the receiving magnetic pole 201 is fixed to 562 GA. The shape of each of the magnetic flux densities of the transporting magnetic pole 106A and the receiving magnetic pole 201 is gradually changed from -3 [°] to +3 [°] according to the angle ratio difference Δ2θ or Δwθ'. Other magnetic poles such as Figure 7 shown. As shown in Table 7, when the angle difference Δwθ'=0° is maintained, the occurrence of abnormal images can be suppressed even when the angle difference Δwθ=-1°. In addition, when the angle difference Δwθ≥0 and Δwθ'≥0, it is preferred to maintain the angle difference Δwθ>0 and Δwθ'>0, and the effect of suppressing the occurrence of abnormal images becomes greater. The effect is that the vicinity of the peak value of the magnetic flux density of the conveying magnetic pole 106A is close to the first feed magnetic pole 105, which not only enhances the magnetic field acting between the receiving magnetic pole 201 and the second feed magnetic pole 202, but also enhances the magnetic field acting between the conveying magnetic pole 106A and the first feed magnetic pole 105, thereby weakening the magnetic field acting between the first feed magnetic pole 105 and the second feed magnetic pole 202. As described above, according to the present embodiment, the occurrence of image defects can be suppressed. That is, in the developing device 1Y of the present embodiment, the developer is fed from the first feeding magnetic pole 105 to the conveying magnetic pole 106A on the first sleeve 33, and is conveyed to the second sleeve 34 based on the magnetic field between the conveying magnetic pole 106A and the receiving magnetic pole 201, and then is transferred from the receiving magnetic pole 201 to the second feeding magnetic pole 202 on the second sleeve 34. In the present embodiment, by configuring the magnetic flux density of the conveying magnetic pole 106A to satisfy the above-mentioned angle difference Δwθ'≥0, the magnetic field acting between the conveying magnetic pole 106A and the first feeding magnetic pole 105 is enhanced compared with the first embodiment, so that the effect of weakening the magnetic field acting between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 becomes larger. Therefore, the movement of the developer between the first feeding magnetic pole 105 and the second feeding magnetic pole 202 can be suppressed, so that the occurrence of the above-mentioned streak-like fog image can be suppressed. <Other embodiments> In addition, the first magnet 36 in the second to fifth embodiments described above can also satisfy the angle difference Δwθ ≥ 0 in the sixth embodiment. In the first to sixth embodiments, the first magnet 36 including the transport magnetic pole 106 satisfying the following first condition or second condition can be used. [First condition] First, in a graph in which the normal component of the magnetic flux density of the transport magnetic pole 106A on the surface of the first sleeve 33 is represented by the magnetic flux density in the abscissa and its angle relative to the rotation direction of the first sleeve 33, the values ​​Lt' and Lh' and the straight lines 10, 11, 12, HLt', HLh', VL11 and VL12 are defined as shown below: Lt': peak value (maximum value of the normal component of the magnetic flux density of the conveying pole 106 on the surface of the first sleeve 33), Lh': half value of the peak value Lt of the magnetic flux density of the transport magnetic pole 106, L10: a straight line connecting the rotation center R1 and point T' (the peak position of the magnetic flux density of the transport magnetic pole 106), L11: a straight line connecting the rotation center R1 and the point Hd′ (a downstream position of the half value of the peak value of the magnetic flux density of the conveying magnetic pole 106 with respect to the rotation direction 81 of the first sleeve 33), L12: a straight line connecting the rotation center R1 and the point Hu' (the upstream position of the half value of the peak value of the magnetic flux density of the conveying magnetic pole 106 with respect to the rotation direction 81 of the first sleeve 33), HLt': a straight line parallel to the abscissa passing through the position of the value Lt', HLh': A straight line parallel to the abscissa passing through the position of the value Lh', VL11: a straight line through point Hu' parallel to the ordinate, and VL12: A straight line passing through point Hd' and parallel to the ordinate. Incidentally, similarly to the sixth embodiment, Hd' is a position on the downstream side of the half-value position of the maximum value of the normal component of the magnetic flux density of the conveying magnetic pole 106 with respect to the rotation direction of the first sleeve 33. Further, similarly to the sixth embodiment, Hu' is a position on the upstream side of the half-value position of the normal component of the magnetic flux density of the conveying magnetic pole 106 with respect to the rotation direction of the first sleeve 33.

[0189] Furthermore, the rectangular area enclosed by the straight lines VL11, VL12, HLt' and HLh' is the area S', and in the graph, the area (shaded portion) obtained by integrating the normal component of the magnetic flux density of the transport magnetic pole 106 from the straight line VL11 to the straight line VL12 according to the angle in the rotation direction of the first sleeve 33 is the area Sa'. In this case, the angle ratio Sa' / S'≥75% is satisfied. [Second condition]

[0190] like Fig. 22 As shown, values ​​C' and D', points Cd', Cu', Dd' and Du', lines L11C, L12C, L11D and L12D, and angles Wc' and Wd' are defined as follows. Incidentally, similarly to the first condition, value Lt is the peak value of the magnetic flux density of the transport pole 106. C': value of 10% of Lt', D': 90% value of Lt', Cd′: a position on the downstream side of the position where the normal component of the magnetic flux density of the conveying magnetic pole 106 becomes the value of C′ with respect to the rotation direction of the first sleeve 33, Cu′: a position on the downstream side of the position where the normal component of the magnetic flux density of the conveying magnetic pole 106 becomes a value C′ with respect to the rotation direction of the first sleeve 33, Dd′: a position on the downstream side of the position where the normal component of the magnetic flux density of the conveying magnetic pole 106 becomes a value D′ with respect to the rotation direction of the first sleeve 33, Du': an upstream position of the position where the normal component of the magnetic flux density of the conveying magnetic pole 106 becomes a value D' with respect to the rotation direction of the first sleeve 33, L11C: a straight line connecting the rotation center R1 of the first sleeve 33 and the point Cd', L12C: The straight line connecting the rotation center R1 and point Cu', L11D: The straight line connecting the rotation center R1 and point Dd', L12D: The straight line connecting the rotation center R1 and point Du', Wc': the angle formed by the line L11C and the line L12C, and Wd': Angle formed by straight line L11D and straight line L12D. In this case, the angle ratio Wd' / Wc'≥45% is satisfied. In the developing device 1Y of the first to sixth embodiments, the developer is fed from the first feed magnetic pole 105 to the conveying magnetic pole 106A on the first sleeve 33, and is conveyed to the second sleeve 34 based on the magnetic field between the conveying magnetic pole 106A and the receiving magnetic pole 201, and then is transferred from the receiving magnetic pole 201 to the second feed magnetic pole 202 on the second sleeve 34. In addition, in the developing device 1Y of other embodiments in which the first magnet 36 includes the conveying magnetic pole 106 satisfying the above-mentioned first condition or the second condition in the first to sixth embodiments, the magnetic field acting between the conveying magnetic pole 106A and the first feed magnetic pole 105 becomes stronger, so that the effect of weakening the magnetic field acting between the first feed magnetic pole 105 and the second feed magnetic pole 202 becomes greater, as compared with the developing device 1Y of the first to sixth embodiments. As a result, the movement of the developer between the first feed magnetic pole 105 and the second feed magnetic pole 202 can be suppressed, thereby achieving the effect of suppressing the occurrence of the above-mentioned stripe fog image. The present invention is not limited to the structure of the above-mentioned embodiment. For example, the imaging device 100 is not limited to the MFP, but may be a copier, a printer or a fax machine. In addition, when the structure of the developer supply screw 42, the developer stirring screw 43 and the developer collecting screw 44 can convey the developer, there is no particular limitation on the structure, and for example, a spiral blade or a paddle blade can be applied. Furthermore, in the above embodiment, the structure in which the first sleeve 33 and the photosensitive drum 28Y rotate in the same direction at mutually opposing positions and the second sleeve 34 and the photosensitive drum 28Y rotate in the same direction at mutually opposing positions is described, but the present invention is not limited thereto. A structure may be adopted in which the rotation center R2 of the second developing roller 31 is arranged above the rotation center R1 of the first developing roller 30, wherein the first sleeve 33 and the photosensitive drum 28Y rotate in opposite directions at positions opposite to each other, and wherein the second sleeve 34 and the photosensitive drum 28Y rotate in opposite directions at positions opposite to each other. That is, in this structure, reverse development is performed so that the photosensitive drum 28 rotates from top to bottom in the vertical direction at the position where the photosensitive drum 28 is opposite to the first developing roller 30, and reverse development is performed so that the photosensitive drum 28 rotates from top to bottom in the vertical direction at the position where the photosensitive drum 28 is opposite to the second developing roller 31. The present invention is also applicable to such a structure. In addition, in the case where three or more developing rollers are provided, the present invention is also applicable to any two developing rollers. While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A developing device, comprising: a developing container configured to contain a developer including a toner and a carrier; a first rotatable member to which a developer contained in the developing container is supplied, and the first rotatable member carries and feeds the developer to a first developing position where an electrostatic latent image formed on an image bearing member is developed; a first magnet fixedly and non-rotatably disposed inside the first rotatable member, wherein the first magnet includes a first developing magnetic pole disposed opposite to the image bearing member at the first developing position, a conveying magnetic pole disposed downstream of the first developing magnetic pole with respect to the rotational direction of the first rotatable member, and a first feeding magnetic pole disposed upstream of the conveying magnetic pole with respect to the rotational direction of the first rotatable member and adjacent to the conveying magnetic pole, the first feeding magnetic pole having a magnetic polarity different from that of the conveying magnetic pole; a second rotatable member disposed opposite to the first rotatable member, the developer being conveyed from the first rotatable member to the second rotatable member by a magnetic field generated by the first magnet, wherein the second rotatable member carries and feeds the developer to a second developing position, the electrostatic latent image being developed at the second developing position, and wherein a rotation direction of the second rotatable member in a position on the outer peripheral surface of the second rotatable member where the second rotatable member is closest to the first rotatable member is opposite to the rotation direction of the first rotatable member in a position on the outer peripheral surface of the first rotatable member where the first rotatable member is closest to the second rotatable member; and a second magnet, the second magnet being fixedly and non-rotatably arranged inside the second rotatable member, wherein the second magnet includes a plurality of magnetic poles, the plurality of magnetic poles including: a second developing magnetic pole arranged opposite to the image bearing member at the second developing position; a receiving magnetic pole, the receiving magnetic pole being arranged upstream of the second developing magnetic pole with respect to the rotation direction of the second rotatable member and having a magnetic polarity different from that of the conveying magnetic pole; and a second feeding magnetic pole, the second feeding magnetic pole being arranged downstream of the receiving magnetic pole with respect to the rotation direction of the second rotatable member and adjacent to the receiving magnetic pole and having a magnetic polarity different from that of the receiving magnetic pole, the receiving magnetic pole being a magnetic pole arranged closest to the conveying magnetic pole among the plurality of magnetic poles, Among them: The position at which the magnetic flux density of the receiving magnetic pole on the outer peripheral surface of the second rotatable member in the normal direction relative to the outer peripheral surface of the second rotatable member is maximum is point T, A position of the receiving magnetic pole on the outer peripheral surface of the second rotatable member at which the magnetic flux density in the normal direction relative to the outer peripheral surface of the second rotatable member is half the maximum value, which is located on the upstream side with respect to the rotation direction of the second rotatable member, is point Hu, A position of the receiving magnetic pole on the outer peripheral surface of the second rotatable member at which the magnetic flux density in the normal direction relative to the outer peripheral surface of the second rotatable member is half the maximum value is a point Hd located on the downstream side with respect to the rotation direction of the second rotatable member, The angle formed by the straight line L20 connecting the rotation center R2 of the second rotatable member and the point T and the straight line L21 connecting the rotation center R2 and the point Hu is wθ21, and When the angle formed by the straight line L20 and the straight line L22 connecting the rotation center R2 and the point Hd is wθ22, The following relations are satisfied: wθ22﹣wθ21≥0.

2. The developing device according to claim 1, wherein: The following relationship is further satisfied: wθ22﹣wθ21>0.

3. The developing device according to claim 1 or 2, wherein: In a graph in which the ordinate represents the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member and the abscissa represents the angle of the second rotatable member relative to the rotation direction of the second rotatable member, exist: The straight line passing through the point T and parallel to the abscissa is HLt, The straight line passing through the points Hu and Hd and parallel to the abscissa is HLh, The straight line passing through the point Hu and parallel to the ordinate is VL21, The straight line passing through the point Hd and parallel to the ordinate is VL22, The area of ​​the rectangle enclosed by the straight lines VL21, VL22, HLt and HLh is S, and In the rectangular region, when an area obtained by integrating the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member from the straight line VL21 to the straight line VL22 according to the angle of the second rotatable member relative to the rotation direction of the second rotatable member is an area Sa, The following relations are satisfied: Sa / S≥65%.

4. The developing device according to claim 3, wherein: The following relationship is further satisfied: Sa / S≥70%.

5. The developing device according to claim 1 or 2, wherein: In a graph in which the ordinate represents the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member and the abscissa represents the angle of the second rotatable member relative to the rotation direction of the second rotatable member, exist: The position located on the upstream side with respect to the rotation direction of the second rotatable member among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 10% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is point Cu, Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 10% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position located on the downstream side with respect to the rotation direction of the second rotatable member is a point Cd, Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 90% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position located on the upstream side with respect to the rotation direction of the second rotatable member is point Du, Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 90% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position on the downstream side with respect to the rotation direction of the second rotatable member is point Dd, The angle formed by the straight line L21C connecting the rotation center R2 and the point Cu and the straight line L22C connecting the rotation center R2 and the point Cd is Wc, and When the angle formed by the straight line L21D connecting the rotation center R2 and the point Du and the straight line L22D connecting the rotation center R2 and the point Dd is Wd, The following relations are satisfied: Wd / Wc≥30%.

6. The developing device according to claim 5, wherein: The following relationship is further satisfied: Wd / Wc≥35%.

7. The developing device according to claim 1 or 2, wherein: exist: The position on the outer peripheral surface of the first rotatable member where the magnetic flux density of the transport magnetic pole in the normal direction relative to the outer peripheral surface of the first rotatable member is maximum is point T′, Among the positions on the outer peripheral surface of the first rotatable member where the magnetic flux density of the transport magnetic pole in the normal direction relative to the outer peripheral surface of the first rotatable member is half the maximum value, the position located on the downstream side with respect to the rotation direction of the second rotatable member is point Hd′, The position of the transport magnetic pole on the outer peripheral surface of the first rotatable member at each position where the magnetic flux density in the normal direction relative to the outer peripheral surface of the first rotatable member is half the maximum value is a point Hu' located on the upstream side with respect to the rotation direction of the first rotatable member, The angle formed by the straight line L10 connecting the rotation center R1 of the first rotatable member and the point T' and the straight line L12 connecting the rotation center R1 and the point Hu' is wθ11, and When the angle formed by the straight line L10 and the straight line L11 connecting the rotation center R1 and the point Hd' is wθ12, The following relations are satisfied: wθ11﹣wθ12≥0.

8. The developing device according to claim 7, wherein: The following relationship is further satisfied: wθ11﹣wθ12>0.

9. A developing device, comprising: a developing container configured to contain a developer including a toner and a carrier; a first rotatable member to which the developer contained in the developing container is supplied, and which carries and feeds the developer to a first developing position where an electrostatic latent image formed on an image bearing member is developed; a first magnet fixedly and non-rotatably disposed inside the first rotatable member, wherein the first magnet includes a first developing magnetic pole disposed opposite to the image bearing member at the first developing position, a conveying magnetic pole disposed downstream of the first developing magnetic pole with respect to the rotational direction of the first rotatable member, and a first feeding magnetic pole disposed upstream of the conveying magnetic pole with respect to the rotational direction of the first rotatable member and adjacent to the conveying magnetic pole, the first feeding magnetic pole having a magnetic polarity different from that of the conveying magnetic pole; a second rotatable member disposed opposite to the first rotatable member, the developer being conveyed from the first rotatable member to the second rotatable member by a magnetic field generated by the first magnet, wherein the second rotatable member carries and feeds the developer to a second developing position, develops the electrostatic latent image at the second developing position, and wherein a rotation direction of the second rotatable member in a position on the outer peripheral surface of the second rotatable member where the second rotatable member is closest to the first rotatable member is opposite to the rotation direction of the first rotatable member in a position on the outer peripheral surface of the first rotatable member where the first rotatable member is closest to the second rotatable member; and a second magnet, the second magnet being fixedly and non-rotatably arranged inside the second rotatable member, wherein the second magnet includes a plurality of magnetic poles, the plurality of magnetic poles including: a second developing magnetic pole arranged opposite to the image bearing member at the second developing position; a receiving magnetic pole, the receiving magnetic pole being arranged upstream of the second developing magnetic pole with respect to the rotation direction of the second rotatable member and having a magnetic polarity different from that of the conveying magnetic pole; and a second feeding magnetic pole, the second feeding magnetic pole being arranged downstream of the receiving magnetic pole with respect to the rotation direction of the second rotatable member and adjacent to the receiving magnetic pole and having a magnetic polarity different from that of the receiving magnetic pole, the receiving magnetic pole being a magnetic pole arranged closest to the conveying magnetic pole among the plurality of magnetic poles, The position where the magnetic flux density of the receiving magnetic pole on the outer peripheral surface of the second rotatable member in the normal direction relative to the outer peripheral surface of the second rotatable member is the maximum is point T, A position of the receiving magnetic pole on the outer peripheral surface of the second rotatable member at which the magnetic flux density in the normal direction relative to the outer peripheral surface of the second rotatable member is half the maximum value, which is located on the upstream side with respect to the rotation direction of the second rotatable member, is point Hu, A position of the receiving magnetic pole on the outer peripheral surface of the second rotatable member at each position where the magnetic flux density in the normal direction relative to the outer peripheral surface of the second rotatable member is half the maximum value is a point Hd located on the downstream side with respect to the rotation direction of the second rotatable member, and In the graph, the ordinate represents the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member, and the abscissa represents the angle of the second rotatable member relative to the rotation direction of the first rotatable member. exist: The straight line passing through the point T and parallel to the abscissa is the straight line HLt, The straight line passing through the points Hu and Hd and parallel to the abscissa is HLh, The straight line passing through the point Hu and parallel to the ordinate is VL21, The straight line passing through the point Hd and parallel to the ordinate is VL22, The area of ​​the rectangle enclosed by the straight lines VL21, VL22, HLt and HLh is S, and In the rectangular region, in the case where an area obtained by integrating the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member from the straight line VL21 to the straight line VL22 according to the angle of the second rotatable member relative to the rotation direction of the second rotatable member is an area Sa, The following relations are satisfied: Sa / S≥75%.

10. A developing device, comprising: a developing container configured to contain a developer including a toner and a carrier; a first rotatable member to which the developer contained in the developing container is supplied, and which carries and feeds the developer to a first developing position where an electrostatic latent image formed on an image bearing member is developed; a first magnet fixedly and non-rotatably disposed inside the first rotatable member, wherein the first magnet includes a first developing magnetic pole disposed opposite to the image bearing member at the first developing position, a conveying magnetic pole disposed downstream of the first developing magnetic pole with respect to the rotational direction of the first rotatable member, and a first feeding magnetic pole disposed upstream of the conveying magnetic pole with respect to the rotational direction of the first rotatable member and adjacent to the conveying magnetic pole, the first feeding magnetic pole having a magnetic polarity different from that of the conveying magnetic pole; a second rotatable member disposed opposite to the first rotatable member, the developer being conveyed from the first rotatable member to the second rotatable member by a magnetic field generated by the first magnet, wherein the second rotatable member carries and feeds the developer to a second developing position, the electrostatic latent image being developed at the second developing position, and wherein a rotation direction of the second rotatable member in a position on the outer peripheral surface of the second rotatable member where the second rotatable member is closest to the first rotatable member is opposite to the rotation direction of the first rotatable member in a position on the outer peripheral surface of the first rotatable member where the first rotatable member is closest to the second rotatable member; and a second magnet, the second magnet being fixedly and non-rotatably arranged inside the second rotatable member, wherein the second magnet includes a plurality of magnetic poles, the plurality of magnetic poles including: a second developing magnetic pole arranged opposite to the image bearing member at the second developing position; a receiving magnetic pole, the receiving magnetic pole being arranged upstream of the second developing magnetic pole with respect to the rotation direction of the second rotatable member and having a magnetic polarity different from that of the conveying magnetic pole; and a second feeding magnetic pole, the second feeding magnetic pole being arranged downstream of the receiving magnetic pole with respect to the rotation direction of the second rotatable member and adjacent to the receiving magnetic pole and having a magnetic polarity different from that of the receiving magnetic pole, the receiving magnetic pole being a magnetic pole arranged closest to the conveying magnetic pole among the plurality of magnetic poles, The position where the magnetic flux density of the receiving magnetic pole on the outer peripheral surface of the second rotatable member in the normal direction relative to the outer peripheral surface of the second rotatable member is the maximum is point T, Among the positions on the outer peripheral surface of the second rotatable member where the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member is half the maximum value, the position on the upstream side with respect to the rotation direction of the second rotatable member is point Hu, and On the outer peripheral surface of the second rotatable member, among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is half the maximum value, the position on the downstream side with respect to the rotation direction of the second rotatable member is a point Hd, and In the graph in which the ordinate represents the magnetic flux density of the receiving magnetic pole in the normal direction relative to the outer peripheral surface of the second rotatable member and the abscissa represents the angle of the second rotatable member relative to the rotation direction of the second rotatable member, exist: Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 10% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position located on the upstream side with respect to the rotation direction of the second rotatable member is point Cu, Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 10% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position on the downstream side with respect to the rotation direction of the second rotatable member is point Cd, Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 90% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position located on the upstream side with respect to the rotation direction of the second rotatable member is point Du, Among the positions where the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member is 90% of the maximum value of the magnetic flux density of the receiving magnetic pole in the normal direction with respect to the outer peripheral surface of the second rotatable member, the position on the downstream side with respect to the rotation direction of the second rotatable member is point Dd, The angle formed by the straight line L21C connecting the rotation center R2 and the point Cu and the straight line L22C connecting the rotation center R2 and the point Cd is Wc, and When the angle formed by the straight line L21D connecting the rotation center R2 and the point Du and the straight line L22D connecting the rotation center R2 and the point Dd is Wd, The following relations are satisfied: Wd / Wc≥40%.

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