Developing device, image forming device

Abstract

The present invention provides a developing device and an image forming apparatus that suppress uneven development in the axial direction of a developing unit, compared to a case where developer released from a rotating member of a rotating pumping unit in a tangential direction of the rotating member is supplied to the developing unit without forcibly changing its flow direction. A developing device comprises: a conveying member that conveys developer in an axial direction while rotating; a developing unit that transfers the developer to an image holder having an electrostatic latent image formed thereon while rotating to develop the electrostatic latent image; a pumping unit having a rotating member that rotates in a circumferential direction and magnetically pumps the developer conveyed by the conveying member and releases the pumped developer in a tangential direction of the rotating member to supply the developer to the developing unit; and a changing unit that changes the flow direction of the developer released in a tangential direction of the rotating member and supplied to the developing unit.

Description

Technical Field

[0001] The present invention relates to a developing device and an image forming device. Background Art

[0002] The developing device described in Patent Document 1 comprises: a stirring and conveying section that stirs the developer while conveying the developer; a developing roller that is arranged in a manner opposite to the image carrier, carries the developer and conveys it to the developing area; a developer supply roller that supplies the developer from the stirring and conveying section to the developing roller; a developer supply space forming section that has a curved surface that maintains a specified distance from the surface of the developer supply roller, and a space with a gap of the specified distance between the curved surface and the surface of the developer supply roller as the developer supply space; and a guiding component that guides the developer from the developer supply roller to the developing roller and is provided with a developer rectification space for accommodating a specified amount of developer.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-221445

[0004] The developing device includes a transport auger that transports developer in the axial direction as it rotates; a developing roller that transfers the developer to an image holder on which an electrostatic latent image is formed, thereby developing the electrostatic latent image; and a scooping roller that scoops up the developer transported by the transport auger and supplies it to the developing roller. The scooping roller comprises a cylindrical magnet roller and a rotating member that is inserted into the magnet roller and rotates in the circumferential direction.

[0005] Conventionally, developer released from the rotating member of the scoop roller in a tangential direction to the rotating member is supplied to the surface of the developing roller without forcibly changing its flow direction. However, with this structure, if the amount of developer drawn by the scoop roller varies in the axial direction of the developing roller, the amount of developer supplied from the scoop roller (scoop unit) to the developing roller (developing unit) will also vary in the axial direction. Consequently, when developing the electrostatic latent image, uneven development may occur in the axial direction of the developing roller. Summary of the Invention

[0006] The present invention aims to suppress uneven development in the axial direction of the developing unit, compared to a case where developer released from a rotating member of a rotating pumping unit in a tangential direction of the rotating member is supplied to the developing unit without forcibly changing its flow direction.

[0007] The developing device according to claim 1 is characterized in that it comprises: a conveying member that conveys a developer in an axial direction while rotating; a developing unit that transfers the developer to an image holder on which an electrostatic latent image is formed while rotating to develop the electrostatic latent image; a sucking unit that has a rotating member that rotates in a circumferential direction and uses a magnetic force to suck up the developer conveyed by the conveying member and releases the sucked developer in a tangential direction of the rotating member to supply it to the developing unit; and a changing unit that changes the flow direction of the developer released in a tangential direction of the rotating member and supplied to the developing unit.

[0008] The developing device according to claim 2 of the present invention is characterized in that, in the developing device according to claim 1, the changing unit has a guide passage for guiding the developer to the developing unit in a manner that changes the flow direction of the developer released in a tangential direction of the rotating rotating member and supplied to the developing unit.

[0009] The developing device involved in scheme 3 of the present invention is characterized in that, in the developing device described in scheme 2, when viewed from the axial direction, in the horizontal direction, the suction unit is arranged at a position different from the developing unit, and the guide channel guides the developer released in the tangential direction of the rotating component to the bottom of the developing unit, and changes the flow direction of the developer guided to the bottom of the developing unit to guide the developer to the lower part of the developing unit.

[0010] The developing device involved in scheme 4 of the present invention is characterized in that, in the developing device described in scheme 1, the changing unit comprises: a passing area for the developer supplied to the developing unit to pass through; a receiving port for receiving the developer released in the tangential direction of the rotating rotating member to the passing area; and a supply port, which, when viewed from the axial direction, opens the passing area along a crossing direction that crosses the direction in which the passing area is opened through the receiving port, and allows the developer supplied from the passing area to the developing unit to pass through.

[0011] The developing device according to claim 5 of the present invention is the developing device according to claim 4, characterized in that an opening width of the receiving port is wider than an opening width of the supply port.

[0012] The developing device according to claim 6 of the present invention is characterized in that, in the developing device according to claim 4 or 5, the pumping unit is arranged at a position different from that of the developing unit in the horizontal direction when viewed from the axial direction, and the supply port is formed below the developing unit.

[0013] The developing device according to claim 7 of the present invention is characterized in that, in the developing device according to claim 3 or 6, the rotating developing unit conveys the developer supplied from the pumping unit in a direction away from the pumping unit without causing the developer to be turned back to the pumping unit.

[0014] An image forming apparatus according to claim 8 of the present invention is characterized by comprising: an image holding member on which an electrostatic latent image is formed; and the developing device according to any one of claims 1 to 7 for developing the electrostatic latent image formed on the image holding member.

[0015] Effects of the Invention

[0016] According to the developing device of the first aspect of the present invention, compared with a case where the developer released from the rotating member of the rotating pumping unit in the tangential direction of the rotating member is supplied to the developing unit without forcibly changing the flow direction, uneven development in the axial direction of the developing unit can be suppressed.

[0017] According to the developing device of the second aspect of the present invention, the flow direction of the developer after being released from the rotating member can be changed without using power.

[0018] According to the developing device of the third aspect of the present invention, compared with a case where the developer released from the rotating member moves without overcoming gravity and is supplied to the developing unit, uneven development in the axial direction of the developing unit can be suppressed.

[0019] According to the developing device of the fourth aspect of the present invention, the flow direction of the developer after being released from the rotating member can be changed without using power.

[0020] According to the developing device of the fifth aspect of the present invention, compared with a case where the opening width of the receiving port is narrower than the opening width of the supply port, uneven development in the axial direction of the developing unit can be suppressed.

[0021] According to the developing device of the sixth aspect of the present invention, compared with a case where the developer released from the rotating member moves without overcoming gravity and is supplied to the developing unit, uneven development in the axial direction of the developing unit can be suppressed.

[0022] According to the developing device of the seventh aspect of the present invention, compared with a case where the rotating developing unit conveys the developer supplied from the pumping unit toward the pumping unit, uneven development in the axial direction of the developing unit can be suppressed.

[0023] According to the image forming apparatus of the eighth aspect of the present invention, it is possible to suppress a decrease in the quality of an output image compared to a case where the developing device according to any one of the first to seventh aspects is not provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0025] Figure 1 is an enlarged cross-sectional view showing a developing device according to an embodiment of the present invention;

[0026] Figure 2 is an enlarged cross-sectional view showing a developing device according to an embodiment of the present invention;

[0027] Figure 3 is a cross-sectional view showing a developing device according to an embodiment of the present invention;

[0028] Figure 4 is a cross-sectional view showing a pickup roller and a supply auger of a developing device according to an embodiment of the present invention;

[0029] Figure 5 is a cross-sectional view showing a supply auger and a stirring auger of a developing device according to an embodiment of the present invention;

[0030] Figure 6 is a diagram showing the configuration of a toner image forming unit and the like of an image forming apparatus according to an embodiment of the present invention;

[0031] Figure 7 is a diagram showing the structure of a fixing device and the like of an image forming apparatus according to an embodiment of the present invention;

[0032] Figure 8 is a structural diagram showing a chain clamp and the like of an image forming apparatus according to an embodiment of the present invention;

[0033] Figure 9 is a diagram schematically illustrating the configuration of an image forming apparatus according to an embodiment of the present invention;

[0034] Figure 10 is an enlarged cross-sectional view showing a developing device according to a modified embodiment of the present invention;

[0035] Figure 11 It is an enlarged cross-sectional view showing a developing device according to a comparative embodiment of the present invention.

[0036] Explanation of symbols

[0037] 10-image forming device, 21-image holding body, 24-developing device, 226-changing unit, 228-guide channel, 232-passing area, 232c-receiving port, 232d-supply port, 240-developing roller (an example of a developing unit), 250-supply screw conveyor (an example of a conveying component), 270-pumping roller (an example of a pumping unit), 270a-sleeve (an example of a rotating component), 270b-magnet roller. DETAILED DESCRIPTION

[0038] according to Figures 1 to 11 An example of a developing device and an image forming apparatus according to an embodiment of the present invention will be described. In the drawings, arrow H indicates the vertical direction of the apparatus (vertical direction), arrow W indicates the width direction of the apparatus (horizontal direction), and arrow D indicates the depth direction of the apparatus (horizontal direction).

[0039] (Image Forming Apparatus 10)

[0040] The image forming apparatus 10 according to this embodiment is an example of an image forming apparatus that forms an image on a sheet member P as a recording medium. Specifically, the image forming apparatus 10 is an electrophotographic image forming apparatus that forms a toner image on the sheet member P. Figure 9 As shown, the image forming apparatus 10 includes a storage unit 50 , a discharge unit 52 , an image forming unit 12 , a conveying mechanism 60 , a reversing mechanism 80 , a fixing device 100 , and a cooling unit 90 .

[0041] [Containment Section 50]

[0042] The receiving portion 50 has the function of receiving the sheet-like component P. Figure 9 As shown in FIG. 1 , the image forming apparatus 10 includes a plurality of (eg, two) storage sections 50 . Sheet members P are selectively fed out from the plurality of storage sections 50 .

[0043] [Discharge portion 52]

[0044] like Figure 9 As shown, the discharge section 52 is a portion that discharges the sheet member P on which an image is formed. Specifically, the sheet member P, after having an image fixed by the fixing device 100 and then cooled by the cooling section 90 , is discharged to the discharge section 52 .

[0045] [Image forming unit 12]

[0046] The image forming unit 12 is an example of an image forming unit that forms an image on the sheet member P. Specifically, Figure 9As shown, the image forming unit 12 has a function of forming an image on a sheet member P by electrophotography. More specifically, the image forming unit 12 includes a toner image forming unit 20 that forms a toner image and a transfer device 30 that transfers the toner image formed by the toner image forming unit 20 onto the sheet member P.

[0047] A plurality of toner image forming units 20 are provided to form a toner image for each color. The image forming apparatus 10 is provided with toner image forming units 20 for four colors: yellow (Y), magenta (M), cyan (C), and black (K). Figure 9 The shown (Y), (M), (C), and (K) represent components corresponding to the above-mentioned colors.

[0048] -Toner Image Forming Unit 20-

[0049] The toner image forming units 20 of each color are basically configured in the same manner except for the toner used. Specifically, Figure 6 As shown, the toner image forming unit 20 of each color has Figure 6 The toner image forming section 20 includes an image holding member 21 (photoreceptor) that rotates in the direction of arrow A and a charger 22 that charges the image holding member 21. The toner image forming section 20 for each color further includes an exposure device 23 that exposes the image holding member 21 charged by the charger 22 to form an electrostatic latent image on the image holding member 21, and a developing device 24 that develops the electrostatic latent image formed on the image holding member 21 by the exposure device 23 using toner. The developing device 24 will be described in detail later.

[0050] -Transfer device 30-

[0051] The transfer device 30 has the following functions: to superimpose the toner images of the image holding bodies 21 of the respective colors on the intermediate transfer body for primary transfer, and to perform secondary transfer of the superimposed toner images onto the sheet member P. Specifically, Figure 9 As shown, the transfer device 30 includes a transfer belt 31 as an intermediate transfer member, a primary transfer roller 33 , and a transfer section 35 .

[0052] The primary transfer roller 33 has a primary transfer position T (reference position T) between the image holding member 21 and the primary transfer roller 33. Figure 6 ) A function of transferring the toner image formed on the image holding member 21 to the transfer belt 31.

[0053] The transfer belt 31 is endless and is wound around a plurality of rollers 32 to determine its posture. By rotating at least one of the plurality of rollers 32, the transfer belt 31 is wound in the direction of arrow B, and the primary transferred image is conveyed to the secondary transfer position NT.

[0054] The transfer section 35 has a function of transferring the toner image transferred onto the transfer belt 31 onto the sheet member P. Specifically, the transfer section 35 includes a secondary transfer section 34 and an opposing roller 36 .

[0055] The opposing roller 36 is positioned below the transfer belt 31, facing the transfer belt 31. The secondary transfer section 34 is positioned inside the transfer belt 31, with the transfer belt 31 positioned between the opposing roller 36 and the secondary transfer section 34. Specifically, the secondary transfer section 34 comprises a corotron. In the transfer section 35, the toner image transferred to the transfer belt 31 is transferred to the sheet member P passing through the secondary transfer position NT using electrostatic force generated by discharge in the secondary transfer section 34.

[0056] [Transmission mechanism 60]

[0057] The conveying mechanism 60 is a mechanism for conveying the sheet-like component P. Specifically, Figure 9 As shown, the transport mechanism 60 has the function of transporting the sheet member P stored in the storage portion 50 to the secondary transfer position NT. The transport mechanism 60 also has the function of transporting the sheet member P from the secondary transfer position NT to the fixing unit 120 (the pressure roller 140 and the heating roller 130 described later). In other words, the transport mechanism 60 has the function of transporting the sheet member P to which the toner image has been transferred toward the fixing unit 120.

[0058] Specifically, the transport mechanism 60 includes a feed roller 62 , a plurality of transport rollers 64 , and a chain gripper 66 .

[0059] The delivery roller 62 delivers the sheet member P stored in the storage unit 50 . The plurality of conveying rollers 64 convey the sheet member P delivered by the delivery roller 62 to the chain gripper 66 or convey the sheet member P delivered by the chain gripper 66 to the cooling unit 90 .

[0060] The chain gripper 66 has a function of holding the front end side of the sheet member P to convey the sheet member P. Specifically, Figure 8 As shown, the chain gripper 66 includes a pair of chains 72 and a plurality of grippers 76 that hold the front end portion of the sheet member P.

[0061] The pair of chains 72 are wound around a pair of sprockets (not shown) arranged at one end and the other end in the axial direction relative to the opposing roller 36, a pair of sprockets (not shown) arranged at one end and the other end in the axial direction relative to the pressure roller 140 described later, and a pair of sprockets 74 (see FIG. 1 ) arranged at intervals in the depth direction of the device. Figure 9 ). As either one of the pair of sprockets rotates, the chain 72 is looped in the direction of arrow C.

[0062] Mounting members 75, each equipped with a clamp 76, are mounted on the pair of chains 72 along the depth direction of the device. A plurality of mounting members 75 are provided, and are fixed to the pair of chains 72 at predetermined intervals along the circumference (circumferential direction) of the chains 72. A plurality of clamps 76 are provided, and are attached to the mounting members 75 at predetermined intervals along the depth direction of the device.

[0063] Then, the chain 72 is looped in the direction of arrow C while the gripper 76 holds the leading end portion of the sheet member P, thereby conveying the sheet member P.

[0064] [Reversal mechanism 80]

[0065] The reversing mechanism 80 is a mechanism for reversing the front and back sides of the sheet member P. Specifically, Figure 9 As shown, the reversing mechanism 80 includes a plurality of (eg, two) conveying rollers 82 , a reversing device 84 , and a plurality of (eg, seven) conveying rollers 86 .

[0066] The plurality of conveying rollers 82 convey the sheet member P conveyed from the fixing device 100 to the reversing device 84. As an example, the reversing device 84 is a device that twists the sheet member P like a Möbius strip by conveying the sheet member P while folding the sheet member P a plurality of times so that the conveying direction of the sheet member P is changed by, for example, 90 degrees each time, thereby reversing the front and back sides of the sheet member P.

[0067] The plurality of conveying rollers 86 are rollers for conveying the sheet member P, the front and back surfaces of which have been reversed by the reversing device 84 , to the chain gripper 66 .

[0068] In addition, a part of the conveying path for conveying the sheet member P in the reversing mechanism 80 is indicated by a dashed line. The reversing mechanism 80 may be a mechanism for reversing the sheet member P by turning it around.

[0069] [Fixing Device 100]

[0070] The fixing device 100 has a function of fixing the toner image transferred onto the sheet member P by the transfer device 30 onto the sheet member P. Figure 7 As shown, the fixing device 100 includes a heating unit 102 that heats the sheet member P being conveyed without contacting the sheet member P, and a blower unit 170 that supports the sheet member P by blowing air to stabilize the position of the sheet member P. The fixing device 100 further includes a fixing unit 120 that heats and pressurizes the sheet member P while in contact with the sheet member P.

[0071] The fixing unit 120 includes a heating roller 130 that heats the sheet P being conveyed so as to come into contact with the sheet P, and a pressure roller 140 that presses the sheet P toward the heating roller 130 .

[0072] [Cooling section 90]

[0073] The cooling unit 90 has a function of cooling the sheet member P heated by the fixing device 100. Figure 9 As shown in FIG, the cooling section 90 includes two cooling rollers 92 arranged in the width direction of the device. Since the two cooling rollers 92 are configured in the same manner, only one of the cooling rollers 92 will be described.

[0074] An air flow generated by an air blowing mechanism (not shown) is generated inside the cooling roller 92. Due to this air flow, the surface temperature of the cooling roller 92 becomes lower than the temperature when the air flow is not generated.

[0075] (Function of Image Forming Apparatus)

[0076] In the image forming apparatus 10 , an image is formed as follows.

[0077] First, the charger 22 of each color is applied with voltage (refer to Figure 6 ) The surface of each color image holder 21 is uniformly negatively charged at a predetermined potential. Next, the exposure device 23 irradiates the charged surface of each color image holder 21 with exposure light according to image data input from the outside to form an electrostatic latent image.

[0078] As a result, an electrostatic latent image corresponding to the image data is formed on the surface of each image holder 21. The developing device 24 for each color then develops the electrostatic latent image, visualizing it as a toner image. The transfer device 30 then transfers the toner image formed on the surface of each color image holder 21 onto a transfer belt 31.

[0079] Therefore, the delivery roller 62 is used to Figure 9 The sheet member P fed from the storage section 50 to the conveyance path of the sheet member P and conveyed by the chain gripper 66 is fed to the secondary transfer position NT where the transfer belt 31 contacts the opposing roller 36. At the secondary transfer position NT, the sheet member P is conveyed while being sandwiched between the transfer belt 31 and the opposing roller 36, whereby the toner image on the surface of the transfer belt 31 is transferred to the surface of the sheet member P.

[0080] Then, the fixing device 100 fixes the toner image transferred onto the surface of the sheet member P to the sheet member P, and the sheet member P is conveyed to the cooling unit 90 . The cooling unit 90 cools the sheet member P with the toner image fixed thereon and discharges it to the discharge unit 52 .

[0081] On the other hand, when forming a toner image on the back side of the sheet member P, the sheet member P, which has passed through the fixing device 100 by being conveyed by the chain gripper 66, is conveyed to the conveying roller 82 of the reversing mechanism 80. The sheet member P conveyed by the conveying roller 82 is reversed on the front and back sides by the reversing device 84. Furthermore, the conveying roller 86 conveys the reversed sheet member P to the chain gripper 66. The chain gripper 66 conveys the sheet member P. Then, the above-described process is repeated to form a toner image on the back side of the sheet member P.

[0082] (Main structure)

[0083] Next, the developing device 24 will be described.

[0084] like Figure 3 As shown, the developing device 24 includes a housing 210, a developing roller 240, a scraper 248, a supply auger 250, a stirring auger 260, and a draw-up roller 270. The housing 210 contains a developer G containing a toner T and a carrier C. The developing roller 240 is an example of a developing unit, the supply auger 250 is an example of a conveying member, and the draw-up roller 270 is an example of a draw-up unit.

[0085] [Housing 210]

[0086] like Figure 3 As shown, an opening 210a is formed on the upper portion of the housing 210, which opens toward the image holding member 21. A developing roller 240 that transfers developer G to the image holding member 21 is housed within the housing 210 with a portion of the developing roller 240 exposed from the opening 210a, with the depth direction of the device as the axial direction.

[0087] Furthermore, a supply passage 212 for conveying the developer G supplied to the developing roller 240 via the pumping roller 270 and an agitation passage 214 for conveying the developer G while agitating the developer G are formed in a lower portion of the housing 210 .

[0088] The supply channel 212 and the stirring channel 214 extend in the depth direction of the device. The supply channel 212 and the stirring channel 214 are sequentially arranged in the width direction of the device from the side close to the developing roller 240 .

[0089] Specifically, the housing 210 includes a partition member 216 extending in the depth direction of the device, which partitions the supply channel 212 and the stirring channel 214 , except for both end portions of the supply channel 212 and the stirring channel 214 in the device depth direction.

[0090] The supply passage 212 is open at its top, and a supply auger 250 is disposed in the supply passage 212 so as to extend in the depth direction of the apparatus. The supply auger 250 conveys the developer G from the near-front side in the depth direction of the apparatus to the rear side thereof as it rotates. Furthermore, the stirring passage 214 is open at its top, and a stirring auger 260 is disposed in the stirring passage 214 so as to extend in the depth direction of the apparatus. The stirring auger 260 conveys the developer G from the rear side in the depth direction of the apparatus to the near-front side thereof as it rotates.

[0091] Furthermore, if Figure 5 As shown, a movement passage 216a is formed on the inner side of the partition member 216 in the depth direction of the device, which allows the developer G to move between the supply passage 212 and the agitation passage 214. In addition, a movement passage 216b is formed on the front side of the partition member 216 in the depth direction of the device, which allows the developer G to move between the supply passage 212 and the agitation passage 214.

[0092] Furthermore, if Figure 3 As shown, a relay space 220 is formed above the supply passage 212 on the vertically central side of the housing 210. This relay space 220 relays the developer G supplied from the supply auger 250 to the developing roller 240. A draw roller 270 is disposed within this relay space 220, extending in the depth direction of the device, with its axial direction being the depth direction of the device. Furthermore, a guide passage 228 is formed within this relay space 220 to guide the developer G released from the draw roller 270 to the developing roller 240. The guide passage 228 will be described in detail later.

[0093] Furthermore, a recovery passage 222 is formed in the housing 210 above the stirring passage 214, extending in the depth direction of the device, for recovering the developer G scraped from the developing roller 240 to the stirring passage 214. The recovery passage 222 is partitioned from the intermediate space 220 by a partition wall 218, the base end of which is connected to the upper end of the partition member 216.

[0094] The partition wall 218 extends upward from the tip of the partition member 216 and curves at its center. The tip of the partition wall 218 faces the outer peripheral surface of the developing roller 240 in the width direction of the device. Furthermore, a layer thickness regulating member 238 is formed on the partition wall 218, projecting toward the developer regulating pole S2 (described later) of the pumping roller 270. This member limits the thickness of the developer G conveyed by the pumping roller 270. The distance between the tip 238a of the layer thickness regulating member 238 and the outer peripheral surface of the pumping roller 270 is constant in the depth direction of the device.

[0095] Furthermore, a restriction plate 224 is formed in the housing 210 at a portion vertically opposed to the lower end of the developing roller 240. The restriction plate 224 is formed in a plate-like shape with its surface facing the width of the device and extending in the depth direction of the device. Furthermore, the distance between the tip 224a of the restriction plate 224 and the outer peripheral surface of the developing roller 240 is constant in the depth direction of the device.

[0096] [Developing roller 240, scraper 248]

[0097] The developing roller 240 is arranged so as to extend in the depth direction of the device with its axial direction being the depth direction of the device. Figure 3 As shown, the sleeve 240a is provided with a cylindrical conductive sleeve 240a rotatably supported by the housing 210, and a cylindrical magnet roller 240b fixed to the housing 210. A gear (not shown) is fixed to the end of the sleeve 240a, and the rotational force is transmitted from the driving source to the gear, so that the sleeve 240a rotates in the direction of arrow R1 in the figure via the gear.

[0098] The scraper 248 is plate-shaped and is arranged to extend in the depth direction of the device. The end of the scraper 248 contacts the portion of the developing roller 240 facing the recovery path 222 .

[0099] In this structure, the developing roller 240 magnetically attracts the carrier C contained in the developer G and conveys it. Furthermore, the restricting plate 224 restricts the layer thickness of the developer G conveyed by the developing roller 240. The developing roller 240 then conveys the developer G, whose layer thickness has been restricted, to a position facing the image holder 21. The developer G on the developing roller 240 then visualizes the electrostatic latent image formed on the image holder 21 as a toner image.

[0100] The scraper 248 scrapes off the developer G that has not been transferred to the electrostatic latent image formed on the image holding member 21 and remains on the developing roller 240 . The developer G scraped off by the scraper 248 is then recovered in the agitation passage 214 through the recovery passage 222 .

[0101] [Supply auger 250]

[0102] like Figure 5 As shown, the supply auger 250 is disposed in the supply passage 212. The supply auger 250 includes a supply shaft 250a extending in the depth direction of the device and spiral supply blades 250b formed on the circumference of the supply shaft 250a. Both ends of the supply shaft 250a are rotatably supported by the wall of the housing 210, and a gear (not shown) is fixed to one end of the supply shaft 250a to receive the rotational force transmitted from the drive source.

[0103] [Mixing auger 260]

[0104] like Figure 5 As shown, the stirring auger 260 is disposed in the stirring passage 214. The stirring auger 260 includes a stirring shaft 260a extending in the depth direction of the device and spiral stirring blades 260b formed on the circumference of the stirring shaft 260a. Both ends of the stirring shaft 260a are rotatably supported by the wall of the housing 210, and a gear (not shown) that receives the rotational force transmitted from the drive source is fixed to one end of the stirring shaft 260a.

[0105] In this structure, the rotating supply auger 250 conveys the developer G in the supply passage 212 from the front side in the depth direction of the device to the back side in the depth direction of the device. The rotating supply auger 250 then transfers the developer G to the stirring auger 260 disposed in the stirring passage 214 via the moving passage 216a formed in the back side in the depth direction of the device.

[0106] The rotating stirring auger 260 stirs the developer G transferred from the supply auger 250 through the movement passage 216a while conveying it from the rear side in the depth direction of the device to the front side in the depth direction of the device. Furthermore, the rotating stirring auger 260 transfers the developer G to the supply auger 250 disposed in the supply passage 212 through the movement passage 216b formed on the front side in the depth direction of the device. In this manner, the developer G circulates between the supply passage 212 and the stirring passage 214 (see arrows in the figure).

[0107] [Pick-up roller 270]

[0108] like Figure 3 As shown, the draw-up roller 270 is disposed within the intermediate space 220 formed above the supply passage 212. Specifically, when viewed from the depth direction of the device, the draw-up roller 270 is disposed above the supply auger 250 (disposed in the supply passage 212) and, in the device width direction, on the opposite side of the image holder 21 with the developing roller 240 interposed therebetween. Furthermore, in the vertical direction, the upper end of the draw-up roller 270 is located above the lower end of the developing roller 240. Furthermore, in the vertical direction, the axial center C1 of the draw-up roller 270 is located below the lower end of the developing roller 240.

[0109] The draw-up roller 270 extends in the depth direction of the device, with its axial direction being the device's depth direction. It comprises a cylindrical, electrically conductive sleeve 270a rotatably supported by the housing 210, and a cylindrical magnet roller 270b fixed to the housing 210. A gear (not shown) is fixed to the end of the sleeve 270a. Rotational force from the drive source is transmitted to the gear, causing the sleeve 270a to rotate in the direction indicated by arrow R2 in the figure (the direction in which the upper portion of the rotating sleeve 270a approaches the developing roller 240) via the gear. The sleeve 270a is an example of a rotating member.

[0110] like Figure 1 As shown, five magnetic poles having S poles or N poles formed on the surface side are arranged at intervals inside the magnet roller 270 b along the circumferential direction of the sleeve 270 a.

[0111] A draw pole S1, which draws developer G from the supply passage 212, is disposed at a position vertically opposed to the supply auger 250. Furthermore, a conveying pole N1, which conveys developer G, a developer regulating pole S2, which regulates the thickness of the developer G layer, a conveying pole N2, which conveys developer G, and a stripping pole S3, which strips developer G from the sleeve 270a, are disposed in this order along the rotational direction of the sleeve 270a. The draw pole S1, the developer regulating pole S2, and the stripping pole S3 are S poles, while the conveying pole N1 and the conveying pole N2 are N poles.

[0112] The developer regulating pole S2 is arranged on the partition wall 218 side relative to the axis C1 of the pumping roller 270 in the device width direction and is arranged to face the layer thickness regulating member 238. The peeling pole S3 is arranged on the developing roller 240 side relative to the axis C1.

[0113] In this structure, if the sleeve 270a is rotated in the direction of arrow R2, Figure 2 As shown, the drawing pole S1 uses magnetic force to draw the developer G conveyed by the supply auger 250 in the supply passage 212 to the sleeve 270a. As the sleeve 270a rotates in the direction of arrow R2, the developer G drawn by the drawing pole S1 is sequentially conveyed to the conveying pole N1, the developer limiting pole S2, the conveying pole N2, and the stripping pole S3.

[0114] When the developer G passes through the developer limiting pole S2, the layer thickness limiting member 238 formed on the partition wall 218 contacts the developer G and limits the layer thickness of the developer G. Furthermore, the peeling pole S3 peels off the sleeve 270a and releases the developer G whose layer thickness has been limited. Specifically, the scooping roller 270 releases the developer G supplied to the developing roller 240 in a tangential direction of the rotating sleeve 270a.

[0115] [Guide Channel 228]

[0116] Next, the guide passage 228 for guiding the developer G released from the scooping roller 270 to the developing roller 240 will be described. Figure 1 As shown, the guide channel 228 is formed in the relay space 220 of the housing 210 by the partition surface 230a, the bottom surface 232a and the side surface 232b.

[0117] A partition surface 230a is formed on the partition plate 230. When viewed from the depth of the device, the partition plate 230 is positioned between the draw roller 270 and the developing roller 240 and has an arcuate shape that follows the outer circumference of the developing roller 240. The lower end of the partition plate 230 extends to a position aligned with the lower end of the developing roller 240 in the vertical direction and is spaced from the tip 224a of the restricting plate 224 in the device width direction. Furthermore, the upper end of the partition plate 230 extends to the upper end of the partition wall 218. The surface of the partition plate 230 that faces the draw roller 270 is the partition surface 230a. Furthermore, a downwardly facing lower surface 230b is formed at the lower end of the partition plate 230.

[0118] By disposing the partition plate 230, the developer G released in the tangential direction of the sleeve 270a contacts the partition surface 230a of the partition plate 230 and is not directly supplied to the developing roller 240. In this way, the partition plate 230 functions as a blocking member that blocks the developer G released in the tangential direction of the sleeve 270a from being directly supplied to the developing roller 240.

[0119] The bottom surface 232a is positioned below the developing roller 240, facing upward and vertically opposite the developing roller 240. When viewed from above, the bottom surface 232a has a rectangular shape extending along the depth direction of the device. Furthermore, the bottom surface 232a is vertically separated from the lower surface 230b of the partition plate 230. At the bottom surface 232a, an edge 233 on the side of the draw-up roller 270 is separated from the draw-up roller 270 in the width direction of the device. Furthermore, when viewed from above, a portion of the bottom surface 232a overlaps with the lower surface 230b. Furthermore, the space between the edge 233 and the lower surface 230b of the partition plate 230 faces the upper portion of the draw-up roller 270 in the width direction of the device and serves as a receiving port 232c for receiving the developer G to the passage area 232, described later.

[0120] Due to the configuration of the bottom surface 232a, a portion of the developer G released in the tangential direction of the sleeve 270a passes through the receiving port 232c and contacts the bottom surface 232a. Then, a portion of the developer G placed on the bottom surface 232a temporarily stops and faces the developing roller 240 in the vertical direction. In this way, the bottom surface 232a functions as an opposing member that causes the developer G that has passed through the receiving port 232c to face the developing roller 240 in the vertical direction.

[0121] Side surface 232b is formed on the plate-shaped limiting plate 224. Specifically, the surface of limiting plate 224 facing the draw-up roller 270 is defined as side surface 232b. When viewed from the width of the device, side surface 232b has a rectangular shape extending in the depth direction of the device. Furthermore, the lower end of side surface 232b is connected to the edge of bottom surface 232a on the side opposite to edge 233.

[0122] Furthermore, when viewed from the depth direction of the device, the rectangular area above the bottom surface 232a and to the side of the side surface 232b serves as the passage area 232 through which the developer G supplied to the developing roller 240 passes. Furthermore, the area between the upper end of the side surface 232b and the lower surface 230b of the partition plate 230 serves as the supply port 232d through which the developer G supplied from the passage area 232 to the developing roller 240 passes. In other words, when viewed from the depth direction of the device, the supply port 232d opens the passage area 232 in a direction intersecting the direction in which the receiving port 232c opens the passage area 232.

[0123] Here, in this embodiment, the opening width ( Figure 2 L01) is narrower than the opening width of the receiving port 232c ( Figure 2 In other words, the opening width L02 of the receiving port 232c is wider than the opening width L01 of the supply port 232d.

[0124] By arranging the side surface 232b, the developer G placed on the bottom surface 232a is blocked and guided to the developing roller 240. In this way, the side surface 232b functions as a blocking member that blocks the developer G placed on the bottom surface 232a.

[0125] In this structure, if Figure 2 As shown, the developer G released in the tangential direction of the rotating sleeve 270a flows through the receiving port 232c and flows into the passing area 232. The developer G that has flowed into the passing area 232 is supplied to the developing roller 240 through the supply port 232d. In this way, the developer G released in the tangential direction of the rotating sleeve 270a changes its flow direction and is supplied to the developing roller 240.

[0126] That is, the guide passage 228 guides the developer G released in the tangential direction of the rotating sleeve 270a to the bottom of the developing roller 240, and changes the flow direction of the developer G guided to the bottom of the developing roller 240 to guide the developer G to the lower side of the developing roller 240. In this way, the changing unit 226 for changing the flow direction of the developer G is formed to include the guide passage 228.

[0127] (Function of the main structure)

[0128] Next, the functions of the main components will be described in comparison with the developing device 424 according to the comparative embodiment. First, the structure of the developing device 424 according to the comparative embodiment will be described mainly in terms of the differences from the developing device 24.

[0129] [Developing device 424]

[0130] like Figure 11 As shown, the draw-up roller 470 provided in the developing device 424 is positioned above the supply auger 250 (located in the supply passage 212) when viewed from the depth direction of the device, and is positioned on the opposite side of the image holder 21 with the developing roller 240 interposed therebetween in the device width direction. Furthermore, in the vertical direction, the upper end of the draw-up roller 470 is positioned above the lower end of the developing roller 240. Furthermore, in the vertical direction, the axial center C2 of the draw-up roller 470 is positioned above the lower end of the developing roller 240.

[0131] The draw-up roller 470 is positioned opposite the lower portion of the developing roller 240 in the width direction of the device and includes a sleeve 470a and a magnet roller sleeve 470b. The draw-up roller 470 differs from the draw-up roller 270 only in its position; the rest of its structure is the same as that of the draw-up roller 270.

[0132] The guide passage 428 that guides the developer G released from the scooping roller 470 to the developing roller 240 is formed to include a partition surface 430 a and a guide surface 440 a .

[0133] The partition surface 430a is formed on the partition plate 430. The partition plate 430 is arranged above the scooping roller 470 to vertically partition the guide passage 428 from the recovery passage 222. The surface of the partition plate 430 facing the scooping roller 470 is the partition surface 430a.

[0134] The guide surface 440a is formed on the guide plate 440. When viewed from the depth of the device, the guide plate 440 is positioned between the developing roller 240 and the draw-up roller 470 and extends along the depth of the device. Specifically, the guide plate 440 is tilted so that the developing roller 240 side is positioned lower than the draw-up roller 470 side when viewed from the depth of the device. Furthermore, in the vertical direction, the edge of the guide plate 440 on the draw-up roller 470 side is positioned below the top end of the draw-up roller 470 and above the axial center C2 of the draw-up roller 470. The upward-facing surface of the guide plate 440 is designated as the guide surface 440a.

[0135] [Function of Developing Devices 24 and 424]

[0136] like Figure 5As shown, the rotating supply auger 250 and stirring auger 260 convey the developer G while stirring the developer G. Thus, the developer G circulates between the supply passage 212 and the stirring passage 214. Here, the developer G conveyed by the supply auger 250 is turned back to the inner side in the depth direction of the device and is transferred to the stirring auger 260.

[0137] Therefore, in the developer G in the supply passage 212, the force that restricts the developer G from moving in the depth direction of the device acts on the inner portion in the depth direction of the device. Figure 4 As shown, the height of the developer G in the supply passage 212 increases from the front side toward the back side in the depth direction of the device. In other words, the surface of the developer G in the supply passage 212 approaches the pickup rollers 270, 470 from the front side toward the back side in the depth direction of the device.

[0138] And, as Figure 2 、 Figure 11 As shown, the draw-up rollers 270 and 470 draw the developer G, which is being conveyed while being stirred by the supply auger 250, into the sleeves 270a and 470a via the draw-up pole S1. As described above, the surface of the developer G in the supply passage 212 approaches the draw-up rollers 270 and 470 as it moves from the front side toward the back side in the depth direction of the device. Therefore, the amount of developer G drawn into the sleeves 270a and 470a toward the back side in the depth direction of the device is greater than the amount drawn toward the front side in the depth direction of the device. In other words, the amount of developer G drawn into the sleeves 270a and 470a varies in the depth direction of the device.

[0139] The developer G drawn up by the sleeves 270a and 470a, which rotate in the direction indicated by arrow R2, is sequentially conveyed to the conveying pole N1, the developer regulating pole S2, the conveying pole N2, and the stripping pole S3. As the developer G passes through the developer regulating pole S2, the layer thickness regulating member 238 contacts the developer G, regulating the thickness of the developer G layer. Furthermore, the stripping pole S3 strips the restricted developer G from the sleeves 270a and 470a, releasing it. Specifically, the drawing rollers 270 and 470 release the developer G supplied to the developing roller 240 in a direction tangential to the rotating sleeves 270a and 470a.

[0140] Hereinafter, the process of supplying the developer G released in the tangential direction of the sleeves 270 a and 470 a to the developing roller 240 by the developing device 424 and the developing device 24 will be described separately.

[0141] -Developing device 424-

[0142] like Figure 11As shown, the axial center C2 of the draw-up roller 470 provided in the developing device 424 is located vertically above the lower end of the developing roller 240 as described above. Furthermore, the draw-up roller 470 faces the lower portion of the developing roller 240 in the device width direction. Furthermore, the guide passage 428, which guides the developer G released from the draw-up roller 470 to the developing roller 240, is formed to include a guide surface 440a.

[0143] Therefore, the developer G released in the tangential direction of the sleeve 470a is not forcibly changed in its flow direction and is supplied to the developing roller 240 under the guidance of the guide surface 440a. In addition, the remaining developer guided by the guide surface 440a but not supplied to the developing roller 240 falls downward from the gap between the guide surface 440a and the developing roller 240 and returns to the supply path 212.

[0144] The developing roller 240 receives the developer G supplied from the scooping roller 470 by the magnetic force of the magnet roller 240 b and conveys the developer G via the rotating sleeve 240 a. The conveyed developer G contacts the restriction plate 224 to limit the layer thickness and is transferred to the image holder 21 .

[0145] This develops the electrostatic latent image formed on the image holder 21. The developer G remaining on the sleeve 240a without being transferred to the image holder 21 is scraped off from the sleeve 240a by the scraper 248 and recovered in the agitation passage 214 through the recovery passage 222.

[0146] -Developing device 24-

[0147] like Figure 1 As shown, the axial center C1 of the pumping roller 270 provided in the developing device 24 is located vertically below the lower end of the developing roller 240 as described above. Furthermore, the guide passage 228 for guiding the developer G released from the pumping roller 270 to the developing roller 240 is formed to include a partition surface 230a, a bottom surface 232a, and side surfaces 232b.

[0148] Therefore, if Figure 2 As shown, a portion of the developer G released in the tangential direction of the sleeve 270a contacts the partition surface 230a and is forced to change its flow direction, passing through the receiving port 232c and flowing into the passing area 232. On the other hand, another portion of the developer G released in the tangential direction of the sleeve 270a does not change its flow direction and flows from the receiving port 232c into the passing area 232. In addition, the remaining developer G released in the tangential direction of the sleeve 270a but not passing through the receiving port 232c falls downward from the gap between the bottom surface 232a and the scooping roller 270 and returns to the supply passage 212.

[0149] After flowing into and passing through area 232, developer G is blocked by side surface 232b and contacts bottom surface 232a. Developer G placed on bottom surface 232a is guided by side surface 232b toward developing roller 240, which is positioned above. By blocking developer G at side surface 232b, the flow direction of developer G is forcibly changed.

[0150] The developer G guided to the developing roller 240 side is then supplied to the developing roller 240 through the supply port 232d with the help of the magnetic force of the magnet roller 240b of the developing roller 240. Furthermore, the remaining developer G that has flowed into the passing area 232 through the receiving port 232c but has not been supplied to the developing roller 240, in turn, passes through the receiving port 232c, falls downward from the gap between the bottom surface 232a and the scooping roller 270, and returns to the supply passage 212. Alternatively, the remaining developer G remains in the passing area 232.

[0151] In this manner, the developer G released in a tangential direction of the rotating sleeve 270a changes its flow direction and is supplied to the upper side of the developing roller 240. In other words, the guide passage 228 guides the developer G released in a tangential direction of the rotating sleeve 270a to below the developing roller 240, changes the flow direction of the developer G guided below the developing roller 240, and supplies the developer G to the lower side of the developing roller 240. Furthermore, in other words, the developer G released in a tangential direction of the rotating sleeve 270a flows into the pass region 232 through the receiving port 232c, and is supplied to the developing roller 240 through the supply port 232d of the pass region 232, which opens in a direction different from the receiving port 232c.

[0152] The developing roller 240 then conveys the scooped developer G via the rotating sleeve 240a. Specifically, the rotating sleeve 240a conveys the developer G supplied from the scooping roller 270 in a direction away from the scooping roller 270. The conveyed developer G then contacts the limiting plate 224, where its layer thickness is restricted, and is then transferred to the image holder 21. This develops the electrostatic latent image formed on the image holder 21. The developer G that remains on the sleeve 240a without being transferred to the image holder 21 is scraped off the sleeve 240a by the scraper 248 and recovered via the recovery passage 222 to the stirring passage 214.

[0153] (Summarize)

[0154] As mentioned above, in Figure 1 In the developing device 24 shown in FIG. 1 , the developer G released in the tangential direction of the sleeve 270a is forcibly changed in its flow direction against the direction of gravity and is supplied to the developing roller 240. Figure 11In the illustrated developing device 424 , the developer G released in the tangential direction of the sleeve 470 a is supplied to the developing roller 240 without forcibly changing its flow direction against the direction of gravity.

[0155] As described above, the amount of developer G drawn into the sleeves 270a and 470a varies in the depth direction of the device. Therefore, in the developing device 24, the developer G released in the tangential direction of the sleeve 270a is forcibly redirected against the force of gravity before being supplied to the developing roller 240. By forcibly redirecting the flow of the developer G against the force of gravity, the developer G can be supplied to the developing roller 240 while minimizing the deviation of the developer G in the depth direction of the device, compared to the case of using the developing device 424. Therefore, in the developing device 24, uneven development in the depth direction of the device can be suppressed, compared to the case of using the developing device 424.

[0156] Furthermore, the developing device 24 includes a guide passage 228 for guiding the developer G to the developing roller 240 so as to change the flow direction of the developer G released in the tangential direction of the sleeve 270a and supplied to the developing roller 240. Therefore, unlike the case where the flow direction of the developer G is forcibly changed by wind pressure, the flow direction of the developer G can be forcibly changed against the direction of gravity without using power.

[0157] Furthermore, in the developing device 24, the guide passage 228 guides the developer G released in the tangential direction of the rotating sleeve 270a to the bottom of the developing roller 240, and changes the flow direction of the developer G to guide the developer G to the lower side of the developing roller 240. As a result, the developer G guided to the lower side of the developing roller 240 is forced to move upward against gravity.

[0158] Therefore, compared to a case where the developer G is moved without overcoming gravity and guided to the developing roller 240 as in the developing device 424, the developer G can be moved in the device depth direction, thereby alleviating deviations in the device depth direction in the developer G guided to the developing roller 240. Thus, compared to a case where the developer G is moved without overcoming gravity and guided to the developing roller 240 as in the developing device 424, uneven development in the device depth direction can be suppressed in the developing device 24.

[0159] Furthermore, in the developing device 24, the rotating sleeve 240a moves in a direction away from the pickup roller 270 ( Figure 2 The developer G supplied from the pickup roller 270 is conveyed by the arrow F01. Therefore, the developer G is rotated in the opposite direction to the sleeve and moves closer to the pickup roller 270 ( Figure 10Compared to a case where the developer G supplied from the draw-up roller 270 is conveyed in the direction of arrow F02, the developer G does not need to be folded back in a U-shape, thereby reducing the deviation of the developer G supplied to the developing roller 240 in the depth direction of the device. Consequently, compared to a case where the developing roller conveys the developer G supplied from the draw-up roller 270 in a direction approaching the draw-up roller 270, uneven development in the depth direction of the device can be suppressed.

[0160] Furthermore, in the developing device 24, the developer G released in the tangential direction of the rotating sleeve 270a flows into the passage area 232 through the receiving port 232c, and is supplied to the developing roller 240 through the supply port 232d of the passage area 232 opened in a direction different from the receiving port 232c.

[0161] Therefore, unlike the case where the flow direction of the developer G is forcibly changed by utilizing wind pressure, for example, the flow direction of the developer G can be forcibly changed without using power.

[0162] Furthermore, in the developing device 24, the opening width L02 of the receiving port 232c is wider than the opening width L01 of the supply port 232d. Therefore, compared to a case where the opening width of the receiving port is narrower than the opening width of the supply port, it is possible to suppress a shortage of the developer G supplied to the developing roller 240 through the supply port 232d. Thus, in the developing device 24, it is possible to suppress uneven development in the depth direction of the device, compared to a case where the opening width of the receiving port is narrower than the opening width of the supply port.

[0163] Furthermore, in the developing device 24, the supply port 232d is formed below the developing roller 240. Therefore, the developer G guided to the lower side of the developing roller 240 through the supply port 232d has to move upward against gravity.

[0164] Therefore, compared to a case where the developer G is moved without overcoming gravity and guided to the developing roller 240 as in the developing device 424, it is possible to reduce the deviation in the depth direction of the device in the developer G guided to the developing roller 240. Therefore, compared to a case where the developer G is moved without overcoming gravity and guided to the developing roller 240 as in the developing device 424, it is possible to suppress uneven development in the depth direction of the device in the developing device 24.

[0165] Furthermore, in the image forming apparatus 10 , by providing the developing device 24 , it is possible to suppress a decrease in the quality of the output image compared to the case where the developing device 424 is provided.

[0166] While a specific embodiment of the present invention has been described in detail, the present invention is not limited to this embodiment. A person skilled in the art will readily appreciate that various other embodiments can be employed within the scope of the present invention. For example, in the above embodiment, the direction of the developer G flow is changed by causing the developer G to flow through the guide passage 228. However, the direction of the developer G flow can also be changed by utilizing wind pressure, magnetic force, or the like. However, in this case, the effect of changing the direction of the developer G flow by causing the developer G to flow through the guide passage 228 is not achieved.

[0167] Furthermore, in the above embodiment, the developer G guided to the lower side of the developing roller 240 moves upward against gravity. However, it is not necessary to overcome gravity by simply changing the flow direction of the developer G supplied to the developing roller 240. However, in this case, the effect of the developer G moving upward against gravity will not occur.

[0168] Furthermore, although not specifically described in the above embodiment, the bottom surface 232a may be configured to have a concave-convex shape extending in the depth direction of the device, thereby generating friction between the developer G flowing into the region 232 and the bottom surface 232a, thereby causing the developer G to move in the depth direction of the device, thereby alleviating the deviation of the developer G in the depth direction of the device.

[0169] The above-described embodiments of the present invention are provided for the purpose of illustration and explanation. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed embodiments. It is obvious that various modifications and variations are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily explain the principles of the present invention and its application. Thus, other technical personnel in this field can understand the present invention through various modifications optimized for specific uses of the assumed various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A developing device comprising: A conveying member that conveys the developer in an axial direction while rotating; a developing unit that transfers a developer to an image holding member on which an electrostatic latent image is formed while rotating, thereby developing the electrostatic latent image; a pumping unit having a rotating member that rotates in a circumferential direction and that uses a magnetic force to pump up the developer conveyed by the conveying member and releases the pumped developer in a tangential direction of the rotating member to supply the developer to the developing unit; and a changing unit for changing a flow direction of the developer released in a tangential direction of the rotating member and supplied to the developing unit, The upper end of the pumping unit is located above the lower end of the developing unit, and the axial center of the pumping unit is located below the lower end of the developing unit.

2. The developing device according to claim 1, wherein The changing unit includes a guide passage for guiding the developer to the developing unit so as to change a flow direction of the developer released in a tangential direction of the rotating rotary member and supplied to the developing unit.

3. The developing device according to claim 2, wherein: When viewed from the axial direction, the pumping unit is arranged at a different position from the developing unit in the horizontal direction. The guide passage guides the developer released in a tangential direction of the rotating member to below the developing unit, and changes a flow direction of the developer guided below the developing unit to guide the developer to a lower portion of the developing unit.

4. The developing device according to claim 1, wherein The changing unit comprises: a passing area for the developer supplied to the developing unit to pass through; a receiving port for receiving the developer released in a tangential direction of the rotating member to the passing area; and The supply port opens the passing area along a direction intersecting with a direction in which the passing area is opened by the receiving port when viewed from the axial direction, and allows the developer supplied from the passing area to the developing unit to pass therethrough.

5. The developing device according to claim 4, wherein The receiving port has an opening width wider than the supply port.

6. The developing device according to claim 4 or 5, wherein: When viewed from the axial direction, the pumping unit is arranged at a different position from the developing unit in the horizontal direction. The supply port is formed below the developing unit.

7. The developing device according to claim 3, wherein: The rotating developing unit conveys the developer supplied from the pumping unit in a direction away from the pumping unit side without causing the developer to be turned back to the pumping unit side.

8. The developing device according to claim 6, wherein: The rotating developing unit conveys the developer supplied from the pumping unit in a direction away from the pumping unit side without causing the developer to be turned back to the pumping unit side.

9. An image forming apparatus comprising: an image holding member having an electrostatic latent image formed thereon; and The developing device according to any one of claims 1 to 8, which develops the electrostatic latent image formed on the image holding member.

Images