Developing device and image forming device

Abstract

The present invention provides a developing device and an image forming device. The developing device comprises: a housing having a first conveying path for supplying developer, a second conveying path arranged adjacent to the first conveying path with a partition wall interposed therebetween, and a connecting path connecting the developer to the second conveying path on the downstream side of the first conveying path in the developer conveying direction; a first conveying member arranged in the first conveying path and having a first rotating shaft that rotates about an axis and a first spiral blade that protrudes from the outer peripheral surface of the first rotating shaft; a second conveying member arranged in the second conveying path and having a second rotating shaft that rotates about an axis and a second spiral blade that protrudes from the outer peripheral surface of the second rotating shaft; and a blade member provided at a position opposite to the connecting path, protruding from the outer peripheral surface of the first rotating shaft, and releasing the developer from a position above the first rotating shaft in the first conveying path to the second conveying path as the first rotating shaft rotates.

Description

Technical Field

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

[0002] 20. The paint sprayer of claim 19, wherein the paint sprayer is mounted on a surface of the paint sprayer and the surface of the paint sprayer are aligned with the plan view of the paint sprayer. The paint sprayer is mounted on a surface of the paint sprayer and the surface of the paint sprayer are aligned with the plan view of the paint sprayer. Summary of the Invention

[0003] The present disclosure relates to a stirring member disposed in a developing device and conveying developer using a spiral blade. The purpose of the stirring member is to suppress developer compression compared to a case where only a reverse spiral blade is provided facing a communication path for supplying developer to an adjacent conveying path.

[0004] According to a first aspect of the present disclosure, there is provided a developing device comprising:

[0005] a housing having a first conveying path for supplying developer, a second conveying path disposed adjacent to the first conveying path with a partition wall interposed therebetween, and a communication path communicating with the second conveying path on a downstream side of the first conveying path in a developer conveying direction;

[0006] a first conveying member disposed in the first conveying path and having a first rotating shaft that rotates about its axis and a first spiral blade that protrudes from an outer peripheral surface of the first rotating shaft;

[0007] a second conveying member disposed in the second conveying path and having a second rotating shaft that rotates about its axis and a second spiral blade that protrudes from an outer peripheral surface of the second rotating shaft; and

[0008] A blade member is provided at a position opposite to the communication path, protrudes from an outer peripheral surface of the first rotating shaft, and releases the developer from a position above the first rotating shaft in the first conveying path to the second conveying path as the first rotating shaft rotates.

[0009] According to the second aspect of the present disclosure, the housing includes a guide portion around the blade member that guides the developer toward the second conveyance path.

[0010] According to the third aspect of the present disclosure, the guide portion is inclined upward from the first conveying member side toward the second conveying member side.

[0011] According to the fourth aspect of the present disclosure, the bottom portion of the second conveyance path is located above the bottom portion of the first conveyance path in the direction of gravity.

[0012] According to the fifth scheme of the present disclosure, the shell has: a third conveying path, which is arranged adjacent to the second conveying path on the opposite side of the first conveying path across other partition walls different from the partition wall; and other connecting paths, which connect the second conveying path and the third conveying path on the downstream side of the conveying direction of the developer in the second conveying path, and the developing device has: a third conveying component, which is arranged in the third conveying path and has a third rotating shaft rotating around the axis, and a third spiral blade protruding from the outer peripheral surface of the third rotating shaft; and other blade components, which are provided on the second conveying component at a position opposite to the other connecting paths and protrude from the outer peripheral surface of the second rotating shaft.

[0013] According to the sixth aspect of the present disclosure, the second conveying member includes a catching blade provided at a position upstream of an upstream end portion of the developer conveying direction in the second conveying path in the other blade member to catch the developer.

[0014] According to the seventh aspect of the present disclosure, an image forming apparatus is provided, comprising: an image retaining member that retains a developer image; a developing roller that supplies developer to the image retaining member; the developing device; and a transfer portion that transfers the developer image from the image retaining member to a medium.

[0015] Effect

[0016] According to the first aspect, compared with a case where only the reverse spiral blade is provided so as to face the communication path for supplying the developer to the adjacent conveying path, compression of the developer is suppressed.

[0017] According to the second aspect, the developer supply direction from the first conveying path to the second conveying path is stabilized compared to a case where the developer supply direction from the first conveying path to the second conveying path is determined only by the blade member.

[0018] According to the third aspect, compared to the case where the guide portion is a horizontal surface, the developer is supplied from above the second conveying member.

[0019] According to the fourth aspect, even when the developer is supplied from the first conveying path to the second conveying path, and the second conveying path has a bottom located above the bottom of the first conveying path in the direction of gravity, the developer is supplied stably.

[0020] According to the fifth aspect, compared to a case where only a spiral blade is arranged at a position of the second conveying path facing other communicating paths, the developer is transferred from the first conveying path and the second conveying path to the third conveying path without being compressed.

[0021] According to the sixth aspect, compared with a case where the intercepting blade is provided on the downstream side of other blade members, the developer is supplied from the second conveying member to the third conveying member more smoothly.

[0022] According to the seventh aspect, degradation of the image formed by the transfer section is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is a diagram schematically illustrating the configuration of an image forming apparatus including a developing device according to this embodiment.

[0024] Figure 2 It is a plan cross-sectional view of the developing device according to this embodiment.

[0025] Figure 3 is Figure 2 Add a cross-sectional view of the surrounding parts to the 3-3 cross-sectional view.

[0026] Figure 4 yes Figure 3 An enlarged cross-sectional view of .

[0027] Figure 5 It shows Figure 3 A partially cutaway perspective view of the arrangement of the first transport member, the second transport member, and the third transport member.

[0028] Figure 6 It is a cross-sectional view showing details of the guide portion. DETAILED DESCRIPTION

[0029] The following describes a method for implementing the present disclosure (hereinafter referred to as the present embodiment). In the following description, arrow H in the figure indicates the vertical direction of the device, arrow W indicates the width direction of the device, and arrow D indicates the depth direction of the device.

[0030] according to Figures 1 to 6 An example of a developing device and an image forming apparatus according to this embodiment will be described.

[0031] Figure 1 An example of the structure of an image forming apparatus including a developing device as an embodiment of the present disclosure is shown. Figure 1 As shown, the image forming apparatus 10 includes a paper storage section 12 for storing paper P as an example of a medium, a conveying section 14, a toner image forming section 20, a fixing device 18, a discharge section 50, and a control section 22. The toner image forming section 20 includes four image forming units 25Y, 25M, 25C, and 25K, and a transfer unit 26. Here, yellow (Y), magenta (M), cyan (C), and black (K) are examples of toner colors. Each image forming unit 25Y, 25M, 25C, and 25K includes at least an image holder 21, a charging device 30, an exposure device 33, and a developing device 24. In each image forming unit 25Y, 25M, 25C, and 25K, a toner image of each color, yellow (Y), magenta (M), cyan (C), and black (K), is formed on the outer peripheral surface of the image holder 21.

[0032] The image holder 21 holds the toner image developed by the developing device 24. The image holder 21 is cylindrical and has a photosensitive layer on its surface. It is driven to rotate in the direction of the arrow by a driving unit (not shown). The developing device 24 develops the latent image formed on the image holder 21 into a toner image. The image holder 21 is an example of an image holder.

[0033] The transfer unit 26 includes a transfer belt 31, primary transfer rollers 32 for each color, a drive roller 34, and a secondary transfer roller 42. The posture of the transfer belt 31 is determined by the four primary transfer rollers 32, the drive roller 34, the support roller 36, and the tensioning roller 38, which are in contact with the inner circumference of the transfer belt 31. A cleaning device 39 is provided downstream of the secondary transfer section 40 in contact with the secondary transfer roller 42. The outer circumference of each image holder 21 disposed in each image forming unit 25Y, 25M, 25C, and 25K is in contact with the outer circumference of the transfer belt 31. The secondary transfer section 40 is an example of a transfer unit.

[0034] The transport unit 14 includes a delivery roller 15 that delivers the paper P from the paper storage unit 12, and multiple pairs of delivery rollers (not shown) along the transport path. The paper P delivered by the delivery roller is then transported to the secondary transfer unit 40, where the drive roller 34 and the secondary transfer roller 42 face each other. The transport unit 14 then delivers the paper P to the fixing device 18. In the fixing device 18, the toner image secondary-transferred onto the paper P is fixed to the paper P. The paper P is then transported by the transport unit 14 to the discharge unit 50.

[0035] In this image forming apparatus 10, exposure light emitted from an exposure device 33 based on image data for each color is incident on the outer peripheral surface of the image holder 21, which has been charged by the charging device 30. This forms a latent image corresponding to the image data for each color on the outer peripheral surface of each image holder 21. The latent image formed on the outer peripheral surface of each image holder 21 is developed into a toner image of each color by each developing device 24. The toner image of each color on the outer peripheral surface of each image holder 21 is primarily transferred onto the outer peripheral surface of the transfer belt 31 by each primary transfer roller 32 positioned opposite the image holder 21.

[0036] Meanwhile, in sync with the timing at which the toner images of each color primarily transferred onto the transfer belt 31 reach the secondary transfer section 40, the paper P is ejected from the paper storage section 12 and conveyed to the secondary transfer section 40, which includes a secondary transfer roller 42. In the secondary transfer section 40, the toner images of each color on the transfer belt 31 are secondarily transferred onto the paper P. The paper P, to which the toner images have been transferred, is then conveyed toward the fixing device 18, where it is heated and pressurized at the contact portion between the pressure roller 18A and the heating roller 18B. After the toner images are fixed to the paper P, the paper P is discharged through the discharge section 50.

[0037] <Structure and basic functions of the developing device>

[0038] Next, the developing device 24 will be described in detail. Since the developing devices 24 for the respective colors have the same structure, the following description will be made using one developing device 24 as an example.

[0039] <Main structure>

[0040] Next, refer to Figure 3 、 4 , 6 pairs of developing device 24 will be described. Figure 2 The directions of the arrows G1, G2, and G3 are described as the downstream side of the developer G conveying direction, and the directions opposite to the arrows are described as the upstream side of the developer G conveying direction. That is, the description corresponds to the upstream and downstream sides of each conveying path (the supply path, the supply path, and the stirring path described later) for conveying the developer G. Figures 2 to 6 In the figure, regarding the developing device 24, the Figure 1 The state when viewed in the direction opposite to the depth direction of the device.

[0041] like Figure 2 as well as Figure 3As shown, a housing 210 serving as a main body of the developing device 24 includes a supply path 212 (described later), a supply path 214 adjacent to the supply path 212, and a stirring path 216 adjacent to the supply path 214 on the opposite side of the supply path 212. Furthermore, a supply auger 250 is rotatably provided in the supply path 212, a supply auger 260 is rotatably provided in the supply path 214, and a stirring auger 270 is rotatably provided in the stirring path 216.

[0042] The housing 210 also includes a suction roller 280 disposed above the supply auger 260 in the device height direction H, a developing roller 240 disposed on the image holding member 21 side of the suction roller 280 , and a layer regulating member 248 .

[0043] The developing roller 240 delivers the developer G to the latent image held by the image holding member 21 at an opening 210A (described later) facing the image holding member 21. The housing 210 contains the developer G containing toner and carrier.

[0044] [Housing 210]

[0045] An opening 210A is formed in the upper portion of the housing 210, opening toward the image holder 21. A developing roller 240 for conveying developer G toward the image holder 21 is housed within the housing 210, with a portion of the roller protruding from the opening 210A. The developing roller 240 is positioned in the axial direction, with the depth of the device being the depth of the roller.

[0046] In the lower portion of the housing 210, a supply path 212 is provided below the developing roller 240 for supplying and transporting the developer G to the developing device 24. Furthermore, there are a supply path 214 provided adjacent to the supply path 212 on the side opposite to the developing roller 240, and an agitation path 216 provided adjacent to the supply path 214 on the side opposite to the supply path 212.

[0047] Supply route

[0048] like Figures 2 to 4 As shown, the supply path 212 is formed by the outer wall of the housing 210 extending along the device depth direction D of the housing 210 and the first partition wall 220 described later. A supply auger 250 described later is rotatably provided in the supply path 212 around the axis of the rotation shaft 252. The supply auger 250 conveys the developer G in the direction of arrow G1. In addition, from the upstream side of the developer conveying direction G1, specifically, from the outside ( Figure 2Specifically, the developer supply unit (not shown) supplies the developer G to the supply path 212 through the developer supply path 300, which is provided on the inner side of the housing 210 in the device depth direction D relative to the region of the developing roller 240 where the developer G is delivered.

[0049] Furthermore, a top portion 218, which will be described later, is formed on the housing 210 around the supply auger 250. Here, the supply path 212 is an example of a first transport path.

[0050] The replenishment path 212 is formed at a position lower than a supply path 214 described later in the apparatus height direction H. Details will be described in the section describing the relationship between the replenishment auger 250 and the supply auger 260 .

[0051] Supply route

[0052] The supply path 214 is formed by being sandwiched between a first partition wall 220 and a second partition wall 230 (described later) extending in the device depth direction D of the housing 210. A supply auger 260 (described later) is rotatably provided in the supply path 214 about the axis of a rotation shaft 262. The supply auger 260 conveys the developer G in the direction indicated by arrow G2. Here, the supply path 214 is an example of a second conveyance path.

[0053] 〔Mixing path〕

[0054] The stirring path 216 is formed by being sandwiched between the second partition wall 230 and the outer wall of the housing 210, which extends along the device depth direction D of the housing 210 and is located on the side opposite to the supply path 212. A stirring auger 270, described later, is rotatably provided in the stirring path 216 about the axis of a rotation shaft 272. The stirring auger 270 conveys the developer G in the direction indicated by arrow G3. Here, the stirring path 216 is an example of a third conveying path.

[0055] 〔First partition wall〕

[0056] The replenishing path 212 and the supply path 214 are partitioned by a first partition wall 220 , except for a first communication path 222 located on the downstream side of the replenishing path 212 in the developer conveying direction.

[0057] The first partition wall 220 is Figure 2 From the upstream side of the developer conveying direction of the supply screw auger 250 in the device depth direction D (at Figure 2 The right end in the middle) and the downstream side (in Figure 2 The inner walls of the shell 210 (left end in the middle) are abutted and fixed.

[0058] A first communication path 222 is formed at the downstream end of the first partition wall 220 in the developer conveying direction G1, at a position corresponding to a release plate 258 and a portion of the reverse spiral blade 256 of the replenishing auger 250 (described later), as a developer G replenishing port that connects the replenishing path 212 with the supply path 214. The first communication path 222 is an example of a communication path.

[0059] 〔Second partition wall〕

[0060] The second partition wall 230 is Figure 2 From the upstream side of the developer conveying direction of the supply screw auger 250 in the device depth direction D (at Figure 2 right end in the middle) to the downstream side (at Figure 2 The second partition wall 230 (the left end in FIG) abuts against and is fixed to the inner walls of the housing 210. A second communication path 232 is formed in the second partition wall 230, upstream of the agitation path 216 in the developer conveying direction G3, as an opening connecting the supply path 214 and the agitation path 216. In other words, the second communication path 232 faces the interface plate 268, reverse spiral blade 266, intercepting spiral blade 267, and spiral blade 264 of the supply auger 260, which will be described later.

[0061] On the other hand, on the downstream side of the second partition wall 230 in the developer conveying direction G3 (at Figure 2 The third connecting path 234 is formed as an opening connecting the stirring path 216 and the supply path 214. In other words, the third connecting path 234 is formed opposite to the position of the spiral blade 274 and the reverse spiral blade 276 of the stirring screw conveyor 270 described later. Figure 2 The developing roller 240 (not shown) is positioned at a position corresponding to the second partition wall 230, which is sandwiched between the second communicating path 232 and the third communicating path 234. Furthermore, in the device depth direction D, the region of the developing roller 240 where the developer G is delivered is positioned between the second communicating path 232 and the third communicating path 234. Here, the second partition wall 230 is an example of another different partition wall, and the second communicating path 232 is an example of another communicating path.

[0062] 〔top〕

[0063] like Figures 3 to 6 As shown, in the supply path 212 of the housing 210, a top portion 218 is formed in a portion corresponding to the first communication path 222, from the upstream side in the rotation direction R1 of the supply auger 250 (described later) to the periphery of a release plate 258 (described later) of the supply auger 250. The top portion 218 covers at least the upper portion of the supply auger 250.

[0064] Specifically, if Figure 6 As shown, the base end of the top portion 218 is positioned within an angle θ1, measured from a perpendicular line to the axis of the rotation shaft 252 of the supply auger 250, toward the upstream side in the rotation direction R1 of the supply auger 250. The angle θ1 is set to a range of 40° to 60°, but is preferably set to 45° to 50°. In this embodiment, θ1 is set to 45°.

[0065] Furthermore, the terminal end of the top portion 218 is within an angle θ2 from the vertical line toward the upstream side in the rotational direction R1 of the supply auger 250. The angle θ2 is set to a range of 0° to 35°, but is preferably set to 15° to 30°. In this embodiment, θ2 is set to 25°.

[0066] Furthermore, the top portion 218 only needs to have a portion that slopes upward from the supply auger 250 side toward the feed auger 260 side. The shape is not limited to an arcuate curve and may be linearly inclined upward from a position upstream in the rotation direction R1 relative to the uppermost portion of the supply auger 250. Furthermore, the top portion 218 may have a shape that is a combination of an arcuate portion and a linear portion.

[0067] The top portion 218 has a function of releasing the developer G supplied by a release plate 258 to be described later, toward the supply path 214 so as to be thrown out from a position above the rotation shaft 252 of the supply auger 250. Here, the top portion 218 is an example of a guide portion.

[0068] Supply Auger

[0069] The supply auger 250 is arranged on the supply path 212 along the device depth direction D of the housing 210. The supply auger 250 includes a rotating shaft 252, a spiral blade 254 formed to protrude from the outer peripheral surface of the rotating shaft 252, an anti-spiral blade 256, and a release plate 258 sandwiched between the spiral blade 254 and the anti-spiral blade 256. The supply auger 250 is connected to a driving unit (not shown) and moves to the supply path 212. Figure 3 Here, the supply auger 250 is an example of a first conveying member.

[0070] The spiral blade 254 moves along Figure 2 The developer G is conveyed in the direction indicated by the arrow G1, and is formed from the inner side in the device depth direction D to a position of the first communication path 222 facing the first partition wall 220. Furthermore, the reverse spiral blade 256 is formed on the downstream side of the replenishing auger 250 in the developer conveying direction G1, facing the first partition wall 220 located on the downstream side of the first communication path 222.

[0071] In addition, in this embodiment, if Figure 2 、 3 As shown, release plates 258 extend along a tangential direction of the outer peripheral surface of rotating shaft 252 when viewed in the longitudinal direction. Two release plates 258 are formed at positions 180 degrees apart in this direction as plate-like members that protrude in directions opposite to the rotational direction of rotating shaft 252. Furthermore, the two ends of release plates 258 in the direction of rotating shaft 252 are connected to spiral blade 254 and counter-spiral blade 256, and the protruding height of release plates 258 is aligned with the protruding height of spiral blade 254. Here, release plates 258 are an example of a blade member.

[0072] The release plate 258 of the supply auger 250 has the function of releasing the developer G supplied from the developer supply unit (not shown) to the supply path 212 from a position above the rotation shaft 252, toward the supply path 214. In this embodiment, the release plate 258 of the supply auger 250, which is arranged in the supply path 212, releases the developer G from a position above the rotation shaft toward the supply path 214, which is located above the supply path 212. The bottom of the supply path 214 is located above the bottom of the supply path 212 and in a range that vertically overlaps with the supply path 212 (the space in which the supply auger 250 is located).

[0073] 〔Supply Auger〕

[0074] The supply auger 260 is arranged in the supply path 214 adjacent to the supply path 212 in the housing 210. The supply auger 260 includes a rotating shaft 262, a spiral blade 264 formed to protrude from the outer peripheral surface of the rotating shaft 262, a reverse spiral blade 266, an intercepting spiral blade 267, and a transfer plate 268 sandwiched between the spiral blade 264 and the reverse spiral blade 266. The supply auger 260 is connected to a driving unit (not shown) to move the supply auger to the supply path 214. Figure 3 The supply auger 260 rotates in the direction of arrow R2. Furthermore, the rotation shaft 262 of the supply auger 260 is thicker than the rotation shaft 252 of the replenishment auger 250 and the rotation shaft 272 of the stirring auger 270. Here, the supply auger 260 is an example of a second conveying member, and the intercepting spiral blade 267 is an example of an intercepting blade.

[0075] The spiral blade 264 is directed toward Figure 2The spiral blade 264 protrudes in the direction of arrow G2, which conveys the developer G, and extends from the inner side in the device depth direction D to just before the first connecting path 222 of the first partition wall 220. Furthermore, the intercepting spiral blade 267 and the reverse spiral blade 266 are formed on the upstream and downstream sides of the first connecting path 222, respectively, downstream of the spiral blade 264 in the developer conveying direction G2. In other words, the intercepting spiral blade 267 can be said to be located upstream of the upstream end of the transfer plate 268 in the developer conveying direction in the supply path 214.

[0076] In addition, the intersection plate 268 is opposite to the first communication path 222 and is formed at a position where the intercepting spiral blade 267 and the reverse spiral blade 266 formed by the two parts divided into the upstream side and the downstream side are sandwiched. Figure 2 、 3 As shown, a plate-shaped component is formed that protrudes from the outer peripheral surface of the rotating shaft 262 in the axial radial direction when viewed along the longitudinal direction of the rotating shaft 262. Furthermore, the two ends of the intersection plate 268 in the direction of the rotating shaft 262 are connected to the intercepting spiral blade 267 and the counter-spiral blade 266. Furthermore, the protruding height of the intersection plate 268 is aligned with the protruding height of the counter-spiral blade 266. Here, the intersection plate 268 is an example of another blade component.

[0077] The supply auger has a function of supplying the developer G to the image holding member 21 and circulating the developer G between the supply path 214 and the stirring path 216 while stirring the developer G.

[0078] 〔Mixing Auger〕

[0079] The stirring auger 270 is arranged adjacent to the supply path 214 on the opposite side of the supply path 214 from the replenishment path 212 in the housing 210. The stirring auger 270 includes a rotating shaft 272, a spiral blade 274 formed to protrude from the outer peripheral surface of the rotating shaft 272, and a reverse spiral blade 276. The stirring auger 270 is connected to a driving unit (not shown) and rotates to rotate. Figure 3 Here, the stirring auger 270 is an example of a third conveying member.

[0080] The spiral blade 274 is directed toward Figure 2The spiral blade 276 protrudes in the direction of the arrow G3 shown in the direction of conveying the developer G, and is formed from the front side in the device depth direction D to the position of the third communication path 234 facing the second partition wall 230. In addition, the reverse spiral blade 276 is continuous with the spiral blade 274 on the downstream side of the spiral blade 274 in the developer conveying direction G3, and is formed from the position facing the third communication path 234 toward the downstream side of the stirring path 216.

[0081] Furthermore, a portion of the spiral blade 274 on the upstream side in the developer conveying direction G3 faces the second communication path 232 of the second partition wall 230 .

[0082] The stirring auger 270 has a function of mixing the developer G circulated from the supply path 214 and the developer G supplied from the supply path 212 while stirring them, and also has a function of circulating the mixed developer G to the supply path 214 .

[0083] Functions of main components

[0084] Reference Figures 2 to 4 The functions of the main components will be described. The developing device 24 will be described with the developer G already stored in the supply path 212 , the supply path 214 , and the stirring path 216 .

[0085] In the developing device 24 , the developer G circulates in the supply path 214 and the agitation path 216 . When the developer G is consumed and reduced, new developer G is supplied from the supply path 212 to the supply path 214 and the agitation path 216 .

[0086] [Supply routes and supply routes]

[0087] The supply path 212 conveys the developer G supplied from a developer supply unit (not shown) in the direction of arrow G1 of the supply auger 250 , and supplies the developer G to the supply path 214 and the stirring path 216 .

[0088] In the supply path 212, the developer G is released and supplied by rotating in the direction of arrow R1 toward the release plate 258 and being guided by the top 218 so as to be thrown toward the supply path 214 through the first connecting path 222 from a position above the rotating shaft 252 of the supply screw conveyor 250.

[0089] In other words, the developer G is released and supplied so as to be poured onto the developer G that has been conveyed in the direction of arrow G2 by the supply auger 260 in the supply path 214 and moved to the position of the first communication path 222 .

[0090] Furthermore, in the supply path 214, the developer G is conveyed from the upstream side of the supply path 214 in the direction indicated by arrow G2 by the rotation of the supply auger 260 in the direction indicated by arrow R2. A portion of the conveyed developer G is supplied to the image holder 21 by a suction roller 280 positioned above the supply auger 260 in the device height direction H, and a developing roller 240 positioned between the suction roller 280 and the image holder 21. The rotary shaft 262 of the supply auger 260 is thicker than the rotary shaft 252 of the replenishing auger 250 and the rotary shaft 272 of the stirring auger 270. In other words, the amount of protrusion of the spiral blade 264 provided on the supply auger 260 from the rotary shaft 262 is reduced, thereby reducing the amount of developer G conveyed by the supply auger 260 compared to the amount of developer G conveyed by the replenishing auger 250 and the stirring auger 270. Thus, variations in the amount of developer G conveyed from the supply auger 260 to the suction roller 280 are suppressed.

[0091] Furthermore, the supply path 212 is located offset downward from the supply path 214 in the device height direction H. Specifically, the bottom of the supply path 214 is located above the bottom of the supply path 212 in the direction of gravity. The bottom of the supply path 214 is located above the bottom of the supply path 212 within the range of overlap with the supply path 212. In this embodiment, the upper portion of the spiral blade 254 of the supply auger 250 is located within the range of overlap with the rotation shaft 262 of the supply auger 260 in the direction of gravity.

[0092] In this state, the developer G in the supply path 212 is supplied so as to be thrown upward from the supply auger 260 through the first communication path 222 by the rotation of the release plate 258 of the supply auger 250 in the direction of arrow R1 .

[0093] Thus, compression of the developer G is suppressed compared to a case where only the reverse spiral blade is provided facing the first communication path 222 and the first communication path 222 supplies (replenishes) the developer G to the supply path 214 adjacent to the replenishment path 212 .

[0094] [Supply path, stirring path, and replenishment path]

[0095] The developer G not supplied to the suction roller 280 is conveyed to the downstream side of the supply path 214 by the rotation of the supply auger 260. The conveyed developer G is partially intercepted by the intercepting spiral blade 267 formed on the upstream side of the transfer plate 268 in the conveying direction and moves to the stirring path 216 through the second communication path 232. The developer G moved to the stirring path 216 is conveyed in the direction of arrow G3 in the stirring path 216 by the rotation of the stirring auger 270 in the direction of arrow R2.

[0096] In the supply path 214, developer G that does not directly flow into the second communication path 232 is conveyed to the position of the transfer plate 268, which is located opposite the second communication path 232. The conveyed developer G is intercepted by the reverse spiral blade 266, which is located downstream of the transfer plate 268 in the conveying direction, and moves through the second communication path 232 to the stirring path 216. At this point, the developer G is scooped up by the rotation of the transfer plate 268 in the direction of arrow R2 and supplied from above to the developer G conveyed in the stirring path 216. The developer G conveyed in the direction of arrow G3 in the stirring path 216 is intercepted by the reverse spiral blade 276, which is located downstream of the stirring path 216 in the conveying direction, and is conveyed to the supply path 214 through the third communication path 234. In other words, the developer G is conveyed between the supply path 214 and the stirring path 216, circulating through the second communication path 232 and the third communication path 234.

[0097] On the other hand, the developer G supplied in the supply path 212 by being thrown out by the rotation of the release plate 258 in the direction of arrow R1 is supplied to the second communication path 232 , and the developer G circulating between the supply path 214 and the stirring path 216 is also supplied.

[0098] The supply auger 260 also has an intercepting spiral blade 267. This intercepting spiral blade 267 is located within the second communication path 232 and adjacent to the spiral blade 264 of the supply auger 260 downstream in the developer conveying direction G2. It intercepts and conveys the developer G to the stirring path 216, and projects in the opposite direction of rotation to the spiral blade 264. The intercepting spiral blade 267 is located opposite the second communication path 232 to temporarily intercept a portion of the developer G, allowing the developer G conveyed in the direction indicated by arrow G2 through the supply path 214 to circulate into the stirring path 216 through the second communication path 232. Furthermore, a reverse spiral blade 266 is provided downstream of the supply path 214 in the developer conveying direction G2, downstream of the transfer plate 268, to prevent the developer G from stagnating on this downstream side. This ensures smooth circulation of the developer G from the supply auger 260 to the stirring auger 270.

[0099] Thus, the developing device 24 of this embodiment includes: a housing 210 having a supply path 212 for supplying developer G; a supply path 214 disposed adjacent to the supply path 212 via a first partition wall 220; and a first communication path 222 communicating with the supply path 214 on the downstream side of the supply path 212 in the direction in which the developer G is conveyed; a supply auger 250 disposed in the supply path 212 and having a rotating shaft 252 that rotates about its axis and a spiral blade 254 that protrudes from the outer peripheral surface of the rotating shaft 252; A supply screw conveyor 260 is arranged in the supply path 214 and has a rotating shaft 262 rotating around the axis and a spiral blade 264 protruding from the outer peripheral surface of the rotating shaft 262; and a release plate 258 is arranged at a position of the supply screw conveyor 250 opposite to the first connecting path 222, extends along the direction of the rotating shaft 252, and protrudes from the outer peripheral surface of the rotating shaft 252. As the rotating shaft 252 rotates, the developer G is released from a position in the supply path 212 that is above the rotating shaft 252 to the supply path 214.

[0100] Thus, compared with a case where only the reverse spiral blade is provided so as to face the communication path for supplying the developer G to the adjacent conveying path, compression of the developer G is suppressed.

[0101] Furthermore, the housing 210 has a top portion 218 around the spiral blade 254 in the replenishment path 212 that guides the developer G toward the supply path 214 .

[0102] Thus, compared to a case where the developer supply direction from the first conveying path to the second conveying path is determined only by the blade member, the developer supply direction from the first conveying path to the second conveying path is stabilized.

[0103] Furthermore, the top portion 218 is inclined upward from the replenishing auger 250 side toward the supply auger 260 side.

[0104] Thus, compared to the case where the guide portion is a horizontal surface, the developer is supplied from above the second conveying member.

[0105] Furthermore, the bottom of the supply path 214 is located above the bottom of the supply path 212 in the range overlapping with the supply path 212 in the direction of gravity.

[0106] Thus, the width dimension of the housing in the developing device is reduced compared to a case where the first conveying path and the second conveying path are located at the same height.

[0107] In addition, the housing 210 has a stirring path 216, which is adjacent to the supply path 214 on the opposite side of the supply path 212 with the second partition wall 230 therebetween; the second communicating path 232 and the third communicating path 234 are connected in the conveying direction of the developer G in the stirring path 216 (in the Figure 2 The developing device 24 has a stirring screw conveyor 270, which is arranged in the stirring path 216 and has a rotating shaft 272 rotating around the axis and a spiral blade 274 protruding from the outer peripheral surface of the rotating shaft 272; and a transfer plate 268, which is arranged on the supply screw conveyor at a position opposite to the second connecting path 232 in a pair of said other connecting paths, extends in the direction along the rotating shaft 262, and protrudes from the outer peripheral surface of the rotating shaft 262.

[0108] This allows the developer to be transferred from the first and second conveying paths toward the third conveying path while suppressing compression of the developer, compared to a case where only the spiral blade is arranged at a position facing other communicating paths of the second conveying path.

[0109] In addition, the supply spiral conveyor 260 has an intercepting spiral blade 267, which is within the range of the second connecting path 232 and is arranged adjacent to the downstream side of the spiral blade 264 in the developer conveying direction. It conveys the developer G to the stirring path 216 while intercepting and protrudes in the opposite rotation direction with the spiral blade 264.

[0110] Thus, compared with a case where the intercepting spiral blade is provided on the upstream side of other blade members, the developer circulates smoothly from the second conveying member to the third conveying member.

[0111] The image forming apparatus of this embodiment includes an image holder 21 that holds a developer image; a developing roller 240 that supplies developer to the image holder 21; the aforementioned developing device 24; and a transfer unit 26 that transfers the developer image from the image holder 21 to the paper P.

[0112] Thus, degradation of the image formed by the transfer unit 26 is suppressed.

[0113] Furthermore, although specific embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the relevant embodiments, and it is obvious to those skilled in the art that various other embodiments exist within the scope of the present disclosure.

[0114] For example, in this embodiment, the replenishment path 212, the supply path 214, and the stirring path 216 are described as being formed adjacent to each other. However, this also includes a developing device 24 in which the replenishment path 212 is replaced with a stirring transport path having a stirring function, and the developer G is stirred and circulated through the stirring transport path and the supply path 214. Even in this case, the developer G is supplied by being thrown toward the adjacent supply path 214, and compression of the developer G circulated from the stirring transport path that replaces the replenishment path 212 to the supply path 214 is suppressed.

[0115] In addition, in this embodiment, the protruding height of the release plate 258 is described as being the same as the protruding height of the spiral blade 254. However, the protruding height of the release plate 258 may be higher or lower than the protruding height of the spiral blade 254. The size can be determined based on the size of the developing device 24, the developer G conveying capacity and conveying speed of the supply path 212, and the like.

[0116] In this embodiment, the release plates 258 are described as being composed of two sheets on the supply auger 250. However, the release plates 258 may be composed of one sheet or three or more sheets. The number of sheets may be determined based on the size of the developing device 24, the developer G conveying capacity and conveying speed of the supply path 212, and the like.

[0117] Furthermore, in this embodiment, the release plate 258 is configured such that its entirety, including the root portion and the front end, extends parallel to the rotation axis 252. However, the release plate 258 may be configured such that its entirety, including at least one of the root portion and the front end, is inclined relative to the rotation axis 252. In other words, the release plate 258 is not limited to a flat plate-like structure and may also have a twisted or curved shape.

[0118] In the present embodiment, the protruding height of the interfacing plate 268 is described as being the same as the protruding height of the spiral blade 264. However, the protruding height of the interfacing plate 268 may be lower or higher than the protruding height of the spiral blade 264. The dimensions may be determined based on the size of the developing device 24, the developer G conveying capacity and conveying speed of the supply path 214 and the stirring path 216, and the like.

[0119] In addition, in this embodiment, the transfer plate 268 is described as being composed of one sheet on the supply auger 260, but it may also be composed of two or more sheets. In this regard, the number of sheets can be determined based on the size of the developing device 24, the developer G conveying capacity and conveying speed of the supply path 212, the amount of developer G circulating in the supply path 214 and the stirring path 216, the circulation speed, etc.

[0120] Furthermore, in the present embodiment, the transfer plate 268 is configured such that the entirety including the root portion and the front end extends parallel to the rotation axis 252. However, the entirety including at least one of the root portion and the front end may be provided so as to be inclined relative to the rotation axis 252. In other words, the transfer plate 268 is not limited to a flat plate-like structure, and may also have a twisted or curved shape.

[0121] The intercepting spiral blade 267 is configured to form a spiral in the opposite direction to the spiral blade 264. However, the intercepting spiral blade 267 does not necessarily need to be a spiral in the opposite direction as long as the force exerted by the intercepting spiral blade 267 in conveying the developer G in the direction of the arrow G2 is weaker than that of the spiral blade 264. For example, even if the intercepting spiral blade 267 is a spiral in the same direction as the spiral blade 264, it may be a spiral with a narrow pitch or a non-spiral disc-shaped shape.

Claims

1. A developing device, wherein: The developing device comprises: a housing having a first conveying path for supplying developer, a second conveying path disposed adjacent to the first conveying path with a partition wall interposed therebetween, and a communication path communicating with the second conveying path on a downstream side of the first conveying path in a developer conveying direction; a first conveying member disposed in the first conveying path and having a first rotating shaft that rotates about its axis and a first spiral blade that protrudes from an outer peripheral surface of the first rotating shaft; a second conveying member disposed in the second conveying path and having a second rotating shaft that rotates about its axis and a second spiral blade that protrudes from an outer peripheral surface of the second rotating shaft; as well as A blade component is arranged at a position opposite to the connecting path, protruding from the outer peripheral surface of the first rotating shaft in a direction along the tangent direction of the outer peripheral surface and toward the opposite side of the rotation direction of the first rotating shaft, and releasing the developer from a position above the first rotating shaft in the first conveying path to the second conveying path as the first rotating shaft rotates.

2. The developing device according to claim 1, wherein The housing includes a guide portion around the blade member that guides the developer toward the second conveyance path.

3. The developing device according to claim 2, wherein: The guide portion is inclined upward from the first conveying member side toward the second conveying member side.

4. The developing device according to claim 1, wherein The bottom of the second conveyance path is located above the bottom of the first conveyance path in the direction of gravity.

5. The developing device according to any one of claims 1 to 4, wherein The housing includes: a third conveying path, which is arranged adjacent to the second conveying path on the opposite side of the first conveying path across another partition wall different from the partition wall; and another connecting path, which connects the second conveying path and the third conveying path on the downstream side of the developer conveying direction in the second conveying path, The developing device comprises: a third conveying member disposed in the third conveying path and having a third rotating shaft that rotates about its axis and a third spiral blade that protrudes from an outer peripheral surface of the third rotating shaft; as well as Another blade member is provided on the second conveying member at a position facing the other communication path and protrudes from the outer peripheral surface of the second rotating shaft.

6. The developing device according to claim 5, wherein The second conveying member includes a catching blade provided at a position upstream of an upstream end portion of the second conveying path in a conveying direction of the developer among the other blade members, and catching the developer.

7. An image forming apparatus, wherein: The image forming device comprises: an image holding body that holds a developer image; a developing roller for supplying a developer to the image holding member; The developing device according to any one of claims 1 to 6; as well as The transfer unit transfers the developer image from the image holding member to a medium.

Images