Developing device and image forming apparatus

Abstract

The invention discloses a developing device and an image forming apparatus. The developing device includes: a developer accommodating unit; a developer holding unit; a first transfer unit; a second transfer unit; a third transfer unit; a first accommodating unit; a second accommodating unit; a third accommodating unit; a first partition unit; a second partition unit; a first inflow unit; a second inflow unit; and a third inflow unit. The purpose of the present invention is, in a developing device that circulates a developer by means of a first conveyance unit and a second conveyance unit, a configuration that conveys the developer separated from a developer holding unit by means of a third conveyance unit, a short circuit of the separated developer to the second conveying unit is suppressed compared with a case where the developer accommodating unit of the third conveying unit and the developer accommodating unit of the second conveying unit are not separated.

Description

Technical Field

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

[0002] In an image forming apparatus that electrostatically transfers and fixes a developer image on an image holding unit onto a medium such as paper to form an image, the techniques described in the following patent documents are known.

[0003] Japanese Patent Publication No. 2003-255700 discloses a structure in which a first shielding plate (11) and a second shielding plate (12) are arranged on the upstream side and the downstream side in the rotation direction relative to the region of a photosensitive body (2) and a developing sleeve (5). In Japanese Patent Publication No. 2003-255700, a voltage is applied to the first shielding plate (11) and the second shielding plate (12) to electrically return the free and splashed charged toner to the developing sleeve (5) side. Summary of the invention

[0004] The technical problem of the present invention is that, in a developing device that circulates developer using a first conveying unit and a second conveying unit, in a structure in which a third conveying unit is used to convey developer separated from a developer holding unit, short circuit of the separated developer to the second conveying unit is suppressed compared to a case in which a developer containing unit of the third conveying unit and a developer containing unit of the second conveying unit are not separated.

[0005] According to a first aspect of the present invention, there is provided a developing device comprising: a developer storing unit, the developer storing unit storing developer; a developer holding unit, the developer holding unit being supported by the developer storing unit and holding the developer on a surface; a first conveying unit, conveying the developer of the developer storing unit, the first conveying unit being arranged in parallel with the developer holding unit and supplying the developer to the developer holding unit; a second conveying unit, conveying the developer of the developer storing unit, the second conveying unit being arranged in parallel with the first conveying unit and conveying the developer in a direction opposite to the first conveying unit; a third conveying unit, conveying the developer of the developer storing unit, the third conveying unit being arranged in parallel with the second conveying unit and conveying the developer separated from the developer holding unit; a first conveying unit, the first conveying unit conveying the developer conveyed by the first conveying unit; a second conveying unit, the second conveying unit conveying the developer conveyed by the second conveying unit; and a third conveying unit, the third conveying unit conveying the developer of the developer storing unit and the third conveying unit conveying the developer conveyed by the second conveying unit. Three receiving units receive the developer transmitted by the third conveying unit; a first separation unit, which is arranged between the first receiving unit and the second receiving unit to separate the first receiving unit and the second receiving unit; a second separation unit, which is arranged between the second receiving unit and the third receiving unit to separate the second receiving unit and the third receiving unit; a first inflow unit, which is arranged on the upstream side of the first separation unit relative to the conveying direction of the first conveying unit, so that the developer flows from the second receiving unit to the first receiving unit; a second inflow unit, which is arranged on the upstream side of the first separation unit relative to the conveying direction of the second conveying unit, so that the developer flows from the first receiving unit to the second receiving unit; and a third inflow unit, which is arranged on the upstream side of the second separation unit relative to the conveying direction of the second conveying unit, so that the developer flows from the third receiving unit to the second receiving unit.

[0006] According to a second aspect of the present invention, in the developing device according to the first aspect, a downstream end of the third inflow unit is arranged on an upstream side than a downstream end of the second inflow unit with respect to a conveying direction of the second conveying unit.

[0007] According to a third aspect of the present invention, in the developing device according to the first aspect, the third inflow unit is arranged upstream of an inflow range of the second inflow unit with respect to a conveying direction of the second conveying unit.

[0008] According to a fourth aspect of the present invention, in the developing device according to the first aspect, the third inflow unit does not overlap at a downstream portion of an inflow range of the second inflow unit with respect to a conveying direction of the second conveying unit.

[0009] According to a fifth aspect of the present invention, in the developing device based on any one of the first to fourth aspects, there is provided a fourth inflow unit for inflow of developer replenished to the developer storage unit, and the fourth inflow unit is arranged at a position corresponding to the third inflow unit.

[0010] According to the sixth aspect of the present invention, in the developing device based on any one of the first to fourth aspects, there is a fourth inflow unit for the developer to be replenished to the developer storage unit, and the downstream end of the fourth inflow unit is arranged on the upstream side compared with the downstream end of the second inflow unit.

[0011] According to the seventh aspect of the present invention, there is provided an image forming device comprising: an image holding unit; the developing device of any one of the first to sixth aspects, which develops the image of the image holding unit; a transfer unit, which transfers the image developed by the developing device from the image holding unit to a medium; and a fixing unit, which fixes the image transferred to the medium.

[0012] (Effect)

[0013] According to the first aspect, in a developing device that circulates developer using a first conveying unit and a second conveying unit, in a structure in which a third conveying unit is used to convey developer separated from a developer holding unit, short circuit of the separated developer to the second conveying unit can be suppressed compared to a case in which the developer storing unit of the third conveying unit and the developer storing unit of the second conveying unit are not separated.

[0014] According to the second aspect, compared with a case where the downstream end of the third inflow unit is not disposed upstream of the downstream end of the second inflow unit, it is possible to suppress the developer from flowing back to the third inflow unit.

[0015] According to the third aspect, compared with a case where the third inflow unit is not disposed in the upstream portion of the inflow range of the second inflow unit, it is possible to suppress the developer from flowing back to the third inflow unit.

[0016] According to the fourth aspect, compared with a case where the downstream portion of the inflow range of the third inflow unit overlaps with the inflow range of the second inflow unit, it is possible to suppress the developer from flowing back to the third inflow unit.

[0017] According to the fifth aspect, the low-concentration developer from the third inflow unit and the newly insufficiently charged developer from the fourth inflow unit can be mixed, so that concentration unevenness of the developer can be suppressed compared with a case where the fourth inflow unit is not arranged at a position corresponding to the third inflow unit.

[0018] According to the sixth aspect, the low-concentration developer from the third inflow unit and the new insufficiently charged developer from the fourth inflow unit can be mixed, so that the concentration unevenness of the developer can be suppressed compared with the case where the downstream end of the fourth inflow unit is not arranged upstream of the downstream end of the second inflow unit.

[0019] According to the seventh aspect, in a developing device that circulates the developer using a first conveying unit and a second conveying unit, in a structure in which the developer separated from the developer holding unit is conveyed using a third conveying unit, short circuit of the separated developer to the second conveying unit can be suppressed compared to a case in which the developer storing unit of the third conveying unit and the developer storing unit of the second conveying unit are not separated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is an overall explanatory diagram of an image forming apparatus of an embodiment;

[0021] Figure 2 is an enlarged explanatory diagram of a visible image forming device of an embodiment;

[0022] Figure 3 is an explanatory diagram of a developing device of an embodiment;

[0023] Figure 4 yes Figure 3 IV-IV line cross-sectional view;

[0024] Figure 5 yes Figure 3 VV line cross-sectional view;

[0025] Figure 6 is an explanatory diagram of the flow of developer in the developing device. Figure 6 (A) is an explanatory diagram of the flow of a developer in a conventional structure. Figure 6 (B) is an explanatory diagram of the flow of the developer of the embodiment;

[0026] Figure 7 is a partial enlarged view of a relative unit of the embodiment;

[0027] Figure 8 This is a diagram to illustrate the relationship between the presence or absence of relative parts and length. Figure 8 (A) is an explanatory diagram of a conventional structure in which no opposing member is provided and the length of the support portion is equal to the sliding friction range. Figure 8(B) is an explanatory diagram of a conventional structure in which no opposing member is provided and the length of the support portion is longer than the sliding friction range. Figure 8 (C) is an explanatory diagram of an example of the present invention in which a relative component is provided and the length of the support portion is the same as the sliding friction range. Figure 8 (D) is an explanatory diagram of another embodiment of the present invention in which a relative component is provided and the length of the support portion is longer than the sliding friction range;

[0028] Fig. 9 is an explanatory diagram of a modification 1 of the embodiment, and is an explanatory diagram when a counter member is arranged on the upstream side of the developing region;

[0029] Fig.10 It is an explanatory diagram of Modification Example 2 of the embodiment. DETAILED DESCRIPTION

[0030] Next, specific examples (hereinafter referred to as embodiments) of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

[0031] In addition, to facilitate understanding of subsequent descriptions, in the accompanying drawings, the front-to-back direction is set as the X-axis direction, the left-to-right direction is set as the Y-axis direction, the up-down direction is set as the Z-axis direction, and the directions or sides indicated by the arrows X, -X, Y, -Y, Z, and -Z are set as front, rear, right, left, top, and bottom, or the front side, rear side, right side, left side, top, and bottom, respectively.

[0032] In the drawings, a mark with “·” in “○” means an arrow pointing from the back side to the front side of the paper, and a mark with “×” in “○” means an arrow pointing from the front side to the back side of the paper.

[0033] In the description using the following drawings, for easy understanding, illustration of components other than those necessary for the description is appropriately omitted.

[0034] [Example]

[0035] Figure 1 It is an overall explanatory diagram of the image forming apparatus according to the embodiment.

[0036] Figure 2 It is an enlarged explanatory diagram of the visible image forming apparatus of the embodiment.

[0037] exist Figure 1 In the figure, a copier U as an example of an image forming device has a user interface UI as an example of an operating unit, a scanning unit U1 as an example of an image reading device, a feeding unit U2 as an example of a medium supply device, an image generating unit U3 as an example of an image recording device, and a medium processing device U4.

[0038] (Description of the user interface UI)

[0039] The user interface UI includes input buttons UIa used for starting copying, setting the number of copies, etc. The user interface UI also includes a display unit UIb for displaying the contents inputted by the input buttons UIa and the status of the copy machine U.

[0040] (Description of Feeding Unit U2)

[0041] exist Figure 1 The feed unit U2 includes a plurality of paper feed trays TR1, TR2, TR3, and TR4 as an example of a medium storage container. In addition, the feed unit U2 includes a medium supply path SH1 for taking out recording paper S as an example of a medium for image recording stored in the paper feed trays TR1 to TR4 and conveying it to the image generating unit U3.

[0042] (Description of Image Generator U3 and Medium Processing Device U4)

[0043] exist Figure 1 In the embodiment, the image generating unit U3 includes an image recording unit U3 a that records an image based on the document image read by the scanning unit U1 on the recording paper S transported from the feeding unit U2 .

[0044] exist Figure 1 and Figure 2 In the image generating unit U3, the driving circuit D of the latent image forming device outputs the corresponding driving signal to the latent image forming devices ROSy, ROSm, ROSc, and ROSk of yellow (Y), magenta (M), cyan (C), and black (K) at a preset time based on the image information input from the scanning unit U1. Below each of the latent image forming devices ROSy to ROSk as an example of a writing unit, a photosensitive drum Py, Pm, Pc, and Pk as an example of an image holding unit is arranged.

[0045] The surfaces of the rotating photosensitive drums Py to Pk are charged in the same manner by charging rollers CRy, CRm, CRc, and CRk, which are examples of charging units. Electrostatic latent images are formed on the surfaces of the charged photosensitive drums Py to Pk by laser beams Ly, Lm, Lc, and Lk, which are examples of latent image writing light output by latent image forming devices ROSy to ROSk. The electrostatic latent images on the surfaces of the photosensitive drums Py to Pk are developed into toner images, which are examples of visible images of yellow (Y), magenta (M), cyan (C), and black (K), by developing devices Gy, Gm, Gc, and Gk, which are examples of developing units.

[0046] In the developing devices Gy to Gk, the developer consumed by development is replenished from toner cartridges Ky, Km, Kc, and Kk, which are examples of developer storage units. The toner cartridges Ky to Kk are detachably mounted on the developer replenishing device U3b.

[0047] The toner images on the surfaces of the photosensitive drums Py to Pk are sequentially transferred in overlapping fashion to an intermediate transfer belt B, which is an example of an intermediate transfer unit, in primary transfer regions Q3y, Q3m, Q3c, and Q3k by primary transfer rollers T1y, T1m, T1c, and T1k, which are an example of a primary transfer unit, thereby forming a color toner image, which is an example of a visible image of multiple colors, on the intermediate transfer belt B. The color toner image formed on the intermediate transfer belt B is conveyed to the secondary transfer region Q4.

[0048] In the case of image information of only K color, only the photosensitive drum Pk and the developing device Gk of K color are used to form only a toner image of K color.

[0049] After the primary transfer, the photosensitive drums Py to Pk are passed through drum cleaners CLy, CLm, CLc, and CLk, which are examples of cleaning units of image holding units, to remove residual developer, paper powder, and other residues adhering to the surfaces.

[0050] In the embodiment, the photosensitive drum Pk, the charging roller CRk, and the drum cleaner CLk are integrated into a photosensitive unit UK of color K as an example of an image holding unit. Also, the photosensitive units UY, UM, and UC of the other colors Y, M, and C are similarly constituted by the photosensitive drums Py, Pm, and Pc, the charging rollers CRy, CRm, and CRc, and the drum cleaners CLy, CLm, and CLc.

[0051] In addition, the K color photosensitive body unit UK and the developing device Gk having the developing roller R0k as an example of the developer holding unit constitute the K color image forming unit UK+Gk. Similarly, the Y, M, C color photosensitive body units UY, UM, UC and the developing devices Gy, Gm, Gc having the developing rollers R0y, R0m, R0c respectively constitute the Y, M, C color image forming units UY+Gy, UM+Gm, UC+Gc.

[0052] Below the photosensitive drums Py to Pk, a belt module BM as an example of an intermediate transfer unit is arranged. The belt module BM includes an intermediate transfer belt B as an example of an image holding unit, a driving roller Rd as an example of a driving unit of the intermediate transfer unit, a tension roller Rt as an example of a tension applying unit, a travel roller Rw as an example of a meandering prevention unit, a plurality of idle rollers Rf as an example of a driven unit, a support roller T2a as an example of a relative unit, and the primary transfer rollers T1y to T1k. The intermediate transfer belt B is supported so as to be rotatable and movable in the direction of the arrow Ya.

[0053] In addition, the primary transfer rollers T1y, T1m, and T1c of the embodiment of the present invention are supported to be able to approach and separate from the photosensitive drums Py, Pm, and Pc. In the case of multi-color printing (color printing), the primary transfer rollers T1y, T1m, and T1c of Y, M, and C colors approach the photosensitive drums Py to Pc and sandwich the intermediate transfer belt B with a preset contact pressure. On the other hand, in the case of single-color printing (monochrome printing) of only black, they are separated from the photosensitive drums Py to Pc.

[0054] A secondary transfer unit Ut is disposed below the support roller T2a. The secondary transfer unit Ut includes a secondary transfer roller T2b as an example of a secondary transfer member. A secondary transfer area Q4 is formed by an area where the secondary transfer roller T2b contacts the intermediate transfer belt B. In addition, the support roller T2a is opposite to the secondary transfer roller T2b across the intermediate transfer belt B. A contact roller T2c as an example of a power supply unit contacts the support roller T2a. A secondary transfer voltage having the same polarity as the charging polarity of the toner is applied to the contact roller T2c.

[0055] The backup roller T2 a , the secondary transfer roller T2 b , and the contact roller T2 c constitute a secondary transfer device T2 as an example of a secondary transfer unit.

[0056] In addition, the secondary transfer unit Ut of the embodiment is configured to be movable in the direction of approaching and separating from the intermediate transfer belt B. The secondary transfer unit Ut moves according to the type of recording paper S used, and changes the contact pressure between the secondary transfer roller T2b and the intermediate transfer belt B. For example, when thick paper is used, the contact pressure can be weakened compared to when ordinary paper is used, and the impact when the front end of the thick paper protrudes into the secondary transfer area Q4 can be alleviated.

[0057] Below the belt module BM, a medium conveying path SH2 is arranged. The recording paper S supplied from the medium supply path SH1 of the feed unit U2 is conveyed to the registration roller Rr as an example of a conveying timing adjustment unit through the conveying roller Ra as an example of a medium conveying unit. The registration roller Rr conveys the recording paper S to the downstream side in accordance with the timing of conveying the toner image formed on the intermediate transfer belt B to the secondary transfer area Q4. The recording paper S fed by the registration roller Rr is guided by the paper guide SGr on the positioning side and the paper guide SG1 before transfer, and is conveyed to the secondary transfer area Q4.

[0058] The toner image on the intermediate transfer belt B is transferred to the recording paper S by the secondary transfer device T2 when passing through the secondary transfer area Q4. In the case of a color toner image, the toner image primarily transferred to the surface of the intermediate transfer belt B is secondarily transferred to the recording paper S together with the overlapping toner image.

[0059] The primary transfer rollers T1y to T1k, the secondary transfer device T2, and the intermediate transfer belt B constitute transfer devices T1y to T1k+T2+B as an example of a transfer unit.

[0060] The intermediate transfer belt B after the secondary transfer is cleaned by a belt cleaner CLB as an example of a cleaning unit of the intermediate transfer unit arranged downstream of the secondary transfer area Q4. The belt cleaner CLB removes residual developer, paper powder, etc. from the intermediate transfer belt B that have not been transferred in the secondary transfer area Q4.

[0061] The recording paper S to which the toner image has been transferred is guided by the paper guide SG2 after the transfer and is transported to the belt transport device BH as an example of a medium transport unit.

[0062] The fixing device F as an example of a fixing unit includes a heating roller Fh as an example of a heating unit and a pressure roller Fp as an example of a pressure unit. The recording paper S is conveyed to the fixing area Q5, which is an area where the heating roller Fh and the pressure roller Fp are in contact. When the toner image on the recording paper S passes through the fixing area Q5, it is heated and pressed by the fixing device F and fixed.

[0063] The image forming units UY+Gy to UK+Gk, the transfer devices T1y to T1k+T2+B, and the fixing device F constitute an image recording section U3a as an example of an image forming unit in the embodiment.

[0064] A switching gate GT1 as an example of a switching unit is provided on the downstream side of the fixing device F. The switching gate GT1 selectively switches the recording paper S passing through the fixing area Q5 to either the discharge path SH3 or the reversing path SH4 on the side of the medium processing device U4. The recording paper S conveyed to the discharge path SH3 is conveyed to the paper conveying path SH5 of the medium processing device U4. A curl correction component U4a as an example of a bending correction unit is arranged in the paper conveying path SH5. The curl correction component U4a corrects the warping, so-called curl, of the recording paper S carried in. The recording paper S with the corrected curl is discharged to the discharge tray TH1 as an example of a medium discharge portion with the image fixing surface of the paper facing upward through the discharge roller Rh as an example of a medium discharge component.

[0065] The recording paper S conveyed to the reversing path SH4 of the image forming unit U3 by the switching gate GT1 is conveyed to the reversing path SH4 of the image forming unit U3 by the second gate GT2 as an example of a switching unit.

[0066] At this time, when the recording paper S is discharged with the image fixing surface facing downward, after the rear end of the recording paper S in the conveying direction passes through the second gate GT2, the conveying direction of the recording paper S is reversed. Here, the second gate GT2 of the embodiment is composed of a film-like elastic member. Therefore, the second gate GT2 allows the recording paper S conveyed to the reversing path SH4 to pass as it is, and when the passing recording paper S is reversed, that is, turned over, it is guided to the conveying paths SH3 and SH5. Then, the reversed recording paper S passes through the curl correction member U4a and is discharged to the discharge tray TH1 with the image fixing surface facing downward.

[0067] The circulation path SH6 is connected to the reversing path SH4 of the image generating unit U3, and a third gate GT3 as an example of a switching unit is disposed at the connection portion. The downstream end of the reversing path SH4 is connected to the reversing path SH7 of the medium processing device U4.

[0068] The recording paper S that passes through the switching gate GT1 and is transferred to the reversing path SH4 is transferred to the reversing path SH7 side of the media processing device U4 through the third gate GT3. The third gate GT3 of the embodiment is composed of a film-like elastic member similar to the second gate GT2. Therefore, the third gate GT3 allows the recording paper S transferred from the reversing path SH4 to pass temporarily, and when the passed recording paper S is turned over, it is guided to the circulation path SH6 side.

[0069] The recording paper S transported to the circulation path SH6 passes through the medium transport path SH2 and is transported to the secondary transfer area Q4 again to perform printing on the second side.

[0070] The paper conveying path SH is constituted by the elements indicated by the above-mentioned reference numerals SH1 to SH7. The paper conveying device SU of the embodiment is constituted by the elements indicated by the above-mentioned reference numerals SH, Ra, Rr, Rh, SGr, SG1, SG2, BH, and GT1 to GT3.

[0071] (Description of the Development Device)

[0072] Figure 3 It is an explanatory diagram of the developing device of the embodiment.

[0073] Figure 4 yes Figure 3 Sectional view along line IV-IV.

[0074] Figure 5 yes Figure 3 VV line section view in.

[0075] In the following description, since the developing devices Gy to Gk of Y, M, C, and K have the same configuration, only the developing device Gk of K color will be described, and descriptions of the developing devices Gy, Gm, and Gc of other colors will be omitted.

[0076] exist Figures 3 to 5 In the embodiment, the developing device Gk as an example of a developing unit has a developing container 1 as an example of a storage portion. In the embodiment, the developing container 1 stores a two-component developer composed of a negatively charged toner and a positively charged magnetic carrier.

[0077] A developing chamber 2 for housing the developing roller R0k is formed inside the developing container 1. The developing chamber 2 extends in the axial direction of the developing roller R0k. On the right side of the developing chamber 2, a supply chamber 3 as an example of a first housing unit is formed adjacently and parallelly.

[0078] exist Figure 4 In the embodiment, a discharge chamber 3a extending rearward is formed at the rear end of the supply chamber 3. A discharge port 3b as an example of a discharge unit is formed on the lower surface of the rear end of the discharge chamber 3a. In addition, a replenishment port 3c as an example of a fourth inflow unit is formed on the upper surface of the front end of the supply chamber 3. New developer from the toner cartridge Kk is replenished to the replenishment port 3c.

[0079] exist Figures 3 to 5 In the embodiment, a stirring chamber 4 as an example of a second storage unit is formed adjacently and parallelly in the supply chamber 3. A reflux chamber 6 as an example of a third storage unit is formed adjacently and parallelly between the developing chamber 2 and the stirring chamber 4. The developing chamber 2, the supply chamber 3, the stirring chamber 4, and the reflux chamber 6 store the developer.

[0080] exist Figure 3 and Figure 4In the embodiment, the developing chamber 2 and the supply chamber 3 are connected over the entire axial area of ​​the developing roller R0k. That is, no partition unit that hinders the inflow of the developer is provided between the developing chamber 2 and the supply chamber 3. The supply chamber 3 and the stirring chamber 4 are separated by a first partition wall 11 as an example of a first partition unit. A first inflow portion 12 as an example of a first inflow unit is formed on the rear end side of the first partition wall 11. A second inflow portion 13 as an example of a second inflow unit is formed on the front end side of the first partition wall 11. The developer can pass through the first inflow portion 12 and the second inflow portion 13 and flow between the supply chamber 3 and the stirring chamber 4.

[0081] exist Figure 3 and Figure 5 In the embodiment, the stirring chamber 4 and the reflux chamber 6 are separated by a second partition wall 16 as an example of a second partition unit. A third inflow portion 17 as an example of a third inflow unit is formed on the front end side of the second partition wall 16. In addition, no inflow unit is provided on the rear end side of the second partition wall 16. Therefore, the developer can pass through the third inflow portion 17 and flow between the stirring chamber 4 and the reflux chamber 6. In addition, in the embodiment, the developing chamber 2 and the reflux chamber 6 are connected in the entire axial area of ​​the developing roller R0k. Therefore, between the developing chamber 2 and the reflux chamber 6, the developer can flow in the entire axial area.

[0082] A supply auger 21 as an example of a first conveying unit is housed in the supply chamber 3. The supply auger 21 has a first rotating shaft 22. Both ends of the first rotating shaft 22 are rotatably supported by the developing container 1. A first gear G1 as an example of a driven unit is supported at one outer end of the first rotating shaft 22.

[0083] A first main conveying blade 23 as an example of a main conveying portion is supported on the first rotating shaft 22. In the embodiment, the first main conveying blade 23 is composed of a spiral blade with a predetermined winding direction. When the first rotating shaft 22 rotates, the first main conveying blade 23 conveys the developer in the supply chamber 3 from the rear to the front. That is, the first main conveying blade 23 conveys the developer from the first inflow portion 12 to the second inflow portion 13.

[0084] A first reverse conveying blade 24 is supported at the front end of the first rotating shaft 22 at a position closer to the front side than the first main conveying blade 23. The first reverse conveying blade 24 is composed of a spiral blade whose winding direction is opposite to that of the first main conveying blade 23. Therefore, when the first rotating shaft 22 rotates, the first reverse conveying blade 24 conveys the developer in the supply chamber 3 toward the rear. The first reverse conveying blade 24 exerts a conveying force in the reverse direction on the developer conveyed forward by the first main conveying blade 23, suppresses the forward movement of the developer, and promotes the inflow of the developer passing through the second inflow portion 13 into the stirring chamber 4.

[0085] A first auxiliary conveying blade 26 is supported at the rear of the first rotating shaft 22 at a position further back than the first main conveying blade 23. The first auxiliary conveying blade 26 is formed such that the spiral in the winding direction is the same as that of the first main conveying blade 23 and the pitch of the spiral (the distance advanced in the axial direction when the first rotating shaft 22 rotates one circle) is smaller than that of the first main conveying blade 23. Therefore, when the first rotating shaft 22 rotates, the first auxiliary conveying blade 26 conveys the developer in the supply chamber 3 toward the front with a conveying force weaker than that of the first main conveying blade 23. Therefore, a part of the developer that passes through the first inflow portion 12 and flows into the supply chamber 3 passes over the first auxiliary conveying blade 26 and flows into the discharge chamber 3a at the rear.

[0086] A discharge conveying blade 27 is supported at the rear end of the first rotating shaft 22 at a position further back than the first auxiliary conveying blade 26. The discharge conveying blade 27 is composed of a spiral blade whose winding direction is opposite to that of the first main conveying blade 23. Therefore, when the first rotating shaft 22 rotates, the discharge conveying blade 27 conveys the developer in the supply chamber 3, especially in the discharge chamber 3a, toward the discharge port 3b at the rear.

[0087] A stirring auger 31 as an example of a second conveying unit is accommodated in the stirring chamber 4. The stirring auger 31 has a second rotating shaft 32. Both ends of the second rotating shaft 32 are rotatably supported by the developing container 1. A second gear G2 as an example of a driven unit is supported at one outer end of the second rotating shaft 32. In the embodiment, the second gear G2 meshes with the first gear G1.

[0088] A second main conveying blade 33 as an example of a main conveying portion is supported on the second rotating shaft 32. In the embodiment, the second main conveying blade 33 is composed of a spiral blade whose winding direction is the same as that of the first main conveying blade 23. When the second rotating shaft 32 rotates, the second main conveying blade 33 conveys the developer in the stirring chamber 4 from the front to the rear. That is, the second main conveying blade 33 conveys the developer from the second inlet portion 13 to the first inlet portion 12.

[0089] A return auger 41 as an example of a third conveying unit is accommodated in the return chamber 6. The return auger 41 has a third rotating shaft 42. Both ends of the third rotating shaft 42 are rotatably supported by the developing container 1. A third gear G3 as an example of a driven unit is supported at one outer end of the third rotating shaft 42. In the embodiment, the third gear G3 meshes with the second gear G2.

[0090] A third main conveying blade 43 as an example of a main conveying portion is supported on the third rotating shaft 42. In the embodiment, the third main conveying blade 43 is composed of a spiral blade having the same winding direction as the first main conveying blade 23. The third main conveying blade 43 conveys the developer in the reflux chamber 6 from the rear to the front when the third rotating shaft 42 rotates. That is, the third main conveying blade 43 conveys the developer in the reflux chamber 6 toward the second inflow portion 13.

[0091] A third reverse conveying blade 44 is supported at the front end of the third rotating shaft 42 at a position forward of the third main conveying blade 43. The third reverse conveying blade 44 is composed of a spiral blade whose winding direction is opposite to that of the third main conveying blade 43. Therefore, when the third rotating shaft 42 rotates, the third reverse conveying blade 44 acts to convey the developer in the return chamber 6 backward. The third reverse conveying blade 44 exerts a conveying force in the reverse direction on the developer conveyed forward by the third main conveying blade 43, suppresses the forward movement of the developer, and promotes the inflow of the developer passing through the third inflow portion 17 into the stirring chamber 4.

[0092] Therefore, the developer in the developing container 1 and the developer in the stirring chamber 4 are stirred and transported to the rear by the rotation of the stirring auger 31. The developer transported to the rear end of the stirring chamber 4 passes through the first inlet 12 and flows into the supply chamber 3. The developer in the supply chamber 3 is stirred and transported from the rear to the front by the rotation of the supply auger 21. At this time, a part of the developer in the supply chamber 3 is supplied to the developing roller R0k. The developer transported to the front end of the supply chamber 3 passes through the second inlet 13 and flows into the stirring chamber 4. Therefore, the developer circulates in the supply chamber 3 and the stirring chamber 4.

[0093] The developer supplied to the developing roller R0k but not used in the development is returned to the return chamber 6. The developer in the return chamber 6 is transported forward while being stirred by the return auger 41. The developer transported to the front end of the return chamber 6 passes through the third inlet 17 and flows into the stirring chamber 4. Therefore, the developer returned from the developing roller R0k is also circulated and reused.

[0094] When the developer is consumed during development, new developer is supplied through the replenishment port 3c. The new developer supplied from the replenishment port 3c flows from the front end of the supply chamber 3 through the second inlet 13 into the stirring chamber 4. Then, the developer is transported while being stirred by the stirring auger 31 in the stirring chamber 4 and is used in development.

[0095] A part of the developer flowing into the discharge chamber 3a is discharged from the discharge port 3b. In this way, the developer in the developing container 1 is gradually discharged from the discharge port 3b, and new developer is replenished from the replenishment port 3c, so that the deteriorated developer can be gradually replaced.

[0096] Furthermore, in the embodiment, the front end of the second partition wall 16 is arranged on the front side compared to the front end of the first partition wall 11. Therefore, the width (inflow range) L2 of the second inflow portion 13 is formed to be larger than the width (inflow range) L3 of the third inflow portion 17. In other words, the downstream end (rear end) of the third inflow portion 17 is arranged on the upstream side (front side) compared to the downstream end (rear end) of the second inflow portion 13 with respect to the developer conveying direction of the stirring auger 31. In addition, it can also be said that the third inflow portion 17 is arranged in the upstream part (front side part) of the inflow range L2 of the second inflow portion 13 with respect to the developer conveying direction of the stirring auger 31. That is, the third inflow portion 17 does not overlap in the downstream part of the inflow range L2 of the second inflow portion 13 with respect to the developer conveying direction of the stirring auger 31.

[0097] In addition, in the embodiment, the replenishment port 3c is arranged at a position corresponding to the third inflow portion 17 in the front-rear direction, that is, the developer conveying direction of the supply auger 21 and the stirring auger 31. In the embodiment, the width L4 of the replenishment port 3c is formed narrower than the third inflow portion 17. Therefore, the replenishment port 3c is arranged at a position overlapping with the third inflow portion 17. Therefore, with respect to the developer conveying direction of the stirring auger 31, the downstream end (rear end) of the replenishment port 3c is arranged on the upstream side (front side) compared with the downstream end (rear end) of the second inflow portion 13.

[0098] Figure 6 is an explanatory diagram of the flow of the developer in the developing device. Figure 6 (A) is an explanatory diagram of the flow of a developer in a conventional structure. Figure 6 (B) is an explanatory diagram of the flow of the developer according to the embodiment.

[0099] exist Figure 6 In (A), in the conventional developing container 01, the reflux chamber 06 and the stirring chamber 04 are not separated. Therefore, the developer returned from the developing roller to the reflux chamber 06 returns to the stirring chamber 04 in sequence at the return position in the axial direction of the developing roller. Therefore, the developer returned to the reflux chamber 06 near the first inflow section 012 is immediately transferred from the stirring chamber 04 to the first inflow section 012, and is easily reused by the developing roller. Therefore, the deterioration of the developer is easy to progress. On the other hand, it takes time for the developer returned from the position separated from the first inflow section 012 to be reused by the developing roller. Therefore, the deterioration of the developer is easy to occur unevenly. That is, when the developer transferred in a short-circuited manner near the first inflow section 012 increases, the deterioration is easy to progress and the unevenness becomes larger. When the unevenness of the degradation of the developer is large, it also becomes a cause of image quality degradation.

[0100] In contrast, in the developing device Gk of the embodiment, the reflow chamber 6 and the stirring chamber 4 are partitioned by the second partition wall 16. Figure 6As shown in (B), all the developer returned from the developing roller R0k to the reflux chamber 6 returns to the stirring chamber 4 from the third inlet portion 17. Therefore, compared with the conventional structure, short circuit of the developer can be suppressed. Therefore, uneven degradation of the developer is suppressed, and degradation of image quality is also suppressed.

[0101] In addition, in the conventional structure, the amount of developer returned from the reflux chamber 06 and the amount of developer circulating in the stirring chamber 04 is greater. Therefore, sometimes the developer will flow back from the stirring chamber 04 to the reflux chamber 06. When the backflow occurs, there is a problem that the reflux chamber 06 is filled with developer, or the flow of developer from the reflux chamber 06 to the stirring chamber 04 is hindered. When the reflux chamber 06 is filled with developer, it is difficult for the developer to flow back from the developing roller to the reflux chamber 06. In this case, the developer separated from the developing roller once adheres again, and the developer that is not sufficiently stirred and charged is reused as it is. When using an insufficiently charged developer, problems such as reduced image quality and increased free developer may occur.

[0102] In contrast, in the embodiment, the third inflow portion 17 is arranged at the upstream portion (front portion) of the inflow range L2 of the second inflow portion 13 with respect to the developer conveying direction of the stirring auger 31. Therefore, most of the developer flowing from the supply chamber 3 into the stirring chamber 4 flows into the rear side of the second inflow portion 13. Therefore, the developer existing in the range of the third inflow portion 17 arranged at the rear side of the second inflow portion 13 becomes relatively small. Thus, it is possible to suppress the developer from flowing back through the third inflow portion 17. Therefore, compared with the previous structure, it is possible to suppress the occurrence of problems such as the re-adhesion of the developer to the developing roller R0k.

[0103] In addition, in the embodiment, a replenishment port 3c is arranged at a position corresponding to the third inflow portion 17. The developer returned from the reflux chamber 6 to the stirring chamber 4 is the developer that has been used once in the development. Therefore, although it is charged, the developer concentration decreases. On the other hand, although the new developer replenished from the replenishment port 3c has a higher developer concentration, it is sometimes not sufficiently stirred and charged. Therefore, in the embodiment, the low-concentration developer flowing in from the third inflow portion 17 and the new developer flowing in from the replenishment port 3c are easy to merge at the upstream end of the stirring chamber 4. Moreover, during the transportation to the first inflow portion 12 at the downstream end of the stirring chamber 4, it is stirred by the stirring augers 31, the low-concentration developer and the new developer are mixed, the concentration of the developer is easy to recover, and the charging is also easy to become sufficient. Figure 6In the conventional structure shown in (A), the concentration of the short-circuited low-concentration developer is difficult to recover, and the mixing with the new developer is also likely to become insufficient. In a state where the concentration of the developer is not recovered or the charging is insufficient, poor development is likely to occur. Therefore, in the embodiment, compared with the conventional structure, the developer is fully mixed, and the occurrence of poor development can be suppressed.

[0104] exist Figure 3 In the embodiment, the developing roller R0k has a fixed magnetic roller 51 as an example of a magnet unit and a rotating developing sleeve 52 as an example of a rotating unit. The developer is attracted and held on the surface of the developing sleeve 52 by the magnetic force of the magnetic roller 51, and the developer is transported to the developing area Q2k by the rotation of the developing sleeve 52.

[0105] In the magnetic roller 51, a developing magnetic pole S1 is arranged at a position corresponding to the developing area Q2k, which is opposite to the photosensitive drum Pk. A conveying magnetic pole N1 is arranged on the upstream side of the developing magnetic pole S1 with respect to the rotation direction of the developing sleeve 52. A trimming magnetic pole S2 as an example of a layer thickness limiting magnetic pole is arranged on the upstream side of the conveying magnetic pole N1 with respect to the rotation direction of the developing sleeve 52. A pickup magnetic pole N2 as an example of an adsorption magnetic pole is arranged on the upstream side of the trimming magnetic pole S2 with respect to the rotation direction of the developing sleeve 52 at a position opposite to the supply auger 21. A stripping magnetic pole N3 as an example of a separation magnetic pole is arranged on the upstream side of the pickup magnetic pole N2 and on the downstream side of the developing magnetic pole S1 with respect to the rotation direction of the developing sleeve 52.

[0106] The developer in the supply chamber 3 is held by the developing sleeve 52 by the magnetic force of the pickup pole N2 .

[0107] A trimmer 55 as an example of a layer thickness limiting member is disposed at a position facing the trimmer magnetic pole S2. The trimmer 55 limits the layer thickness of the developer attached to the developing sleeve 52. Therefore, the developer having a predetermined layer thickness is retained on the surface of the developing sleeve 52 after passing the position of the trimmer 55.

[0108] The developer is held constant in the developing sleeve 52 by the magnetic field between the trimming pole S2 and the transporting pole N1 and the magnetic field between the transporting pole N1 and the developing pole S1, and is sent to the developing area Q2k by the rotation of the developing sleeve 52.

[0109] After passing through the developing area Q2k, the developer is held in the developing sleeve 52 between the developing magnetic pole S1 and the stripping magnetic pole N3 and is sent to the reflux chamber 6. When the developer reaches between the stripping magnetic pole N3 and the pickup magnetic pole N2, the developer is separated from the developing sleeve 52 and flows into the reflux chamber 6 by the magnetic field between the stripping magnetic pole N3 and the pickup magnetic pole N2 of the same polarity.

[0110] Figure 7 It is a partial enlarged view of the relative unit of the embodiment.

[0111] exist Figure 3 , Figure 7 In the embodiment, a charging film 53 as an example of a counter member is supported on a developing container 1 as an example of a developer storage unit. The charging film 53 is arranged to face the developing sleeve 52 on the downstream side of the developing area Q2k with respect to the rotation direction of the developing sleeve 52. The charging film 53 is supported by a film support portion 54 as an example of a supporting unit provided on the downstream side of the developing area Q2k with respect to the rotation direction of the developing sleeve 52. The film support portion 54 is supported on the developing container 1.

[0112] The charging film 53 and the developing sleeve 52 are arranged with a gap therebetween. The gap is such that the developer held on the developing sleeve 52 can slide and rub against the charging film 53 .

[0113] The charged film 53 is made of a material having the same charging polarity as the developer. Therefore, when the developer has a negative charging polarity, a material having a negative charging polarity can be used as the charged film 53. As the material having a negative charging polarity, for example, fluororesins such as PTFE: polytetrafluoroethylene, or PI: polyimide, PP: polypropylene, PVC: polyvinyl chloride, POM: polyoxymethylene (polyacetal), etc. can be used.

[0114] When the charged film 53 is frictionally charged by the developer, the charged film 53 is frictionally charged. When the charged film 53 is frictionally charged, an electric field is generated according to the relationship between the charged potential of the charged film 53 and the developing bias of the developing roller R0k. As an example, when the charged film 53 is PTFE, the inventor's experiment confirmed that when the charged potential is above -1000 [V] and the developing bias is -600 [V], the developing sleeve 52 side is + (positive) and the charged film 53 side is - (negative). As a result, the negatively charged developer is electrostatically attracted to the developing sleeve 52 side. Therefore, when developing in the developing area Q2k, the free and suspended developer is easily adsorbed on the developing sleeve 52 side. As a result, the developer can be restrained from being free compared to the case where there is no charged film 53. Therefore, it is possible to prevent the suspended developer from adhering to the photosensitive drum Pk and causing image quality degradation, and the interior of the copier U from being contaminated by the free developer.

[0115] In particular, compared with the case where a voltage applying device is provided to attract the free developer, a voltage applying device is not required, that is, a power supply, wiring, etc. are not required. Therefore, the increase in the number of parts can be suppressed. Therefore, the cost can be reduced. In addition, there is no need to provide a space for the voltage applying device. Therefore, the miniaturization of the developing device Gk can also be achieved.

[0116] In the embodiment, the charging film 53 rubs against the developer before separation from the developing sleeve 52. Therefore, the charging film 53 is arranged upstream of the peeling magnetic pole N3 in the rotation direction of the developing sleeve 52.

[0117] In addition, the length of the charged film 53 along the rotation direction of the developing sleeve 52 is set to a length corresponding to the width of the developer sliding friction. The developer is in a state along the magnetic lines of force of the magnetic field. Therefore, the closer to the magnetic poles S1 and N3, the easier it is for the developer to be in a so-called spike state, and in the middle position between the magnetic poles S1 and N3, the magnetic spike of the developer is more likely to be in a tilted state. Therefore, in the range where the magnetic spike of the developer is tilted, it is difficult for the developer to slide and rub on the charged film 53, and in the range where the spike is upright, the developer is easy to slide and rub on the charged film 53. The charged film 53 of the embodiment is configured corresponding to the range of sliding friction previously obtained in experiments, etc., and is set to a length corresponding to the range of sliding friction. As an example, the charged film 53 of the embodiment is also configured in the film support portion 54 at a position close to the downstream side of the stripping magnetic pole N3. Therefore, compared with the case where the charged film 53 is also configured in the range where there is no sliding friction, it is possible to suppress the charged film 53 from becoming unnecessary longer. Therefore, the manufacturing cost of the charged film 53 can be suppressed.

[0118] Figure 8 This is a diagram to illustrate the relationship between the presence or absence of relative parts and length. Figure 8 (A) is an explanatory diagram of a conventional structure in which no opposing member is provided and the length of the support portion is equal to the sliding friction range. Figure 8 (B) is an explanatory diagram of a conventional structure in which no opposing member is provided and the length of the support portion is longer than the sliding friction range. Figure 8 (C) is an explanatory diagram of an example of the present invention in which a relative component is provided and the length of the support portion is the same as the sliding friction range. Figure 8 (D) is an explanatory diagram of another embodiment of the present invention in which a counter member is provided and the length of the support portion is longer than the sliding friction range.

[0119] exist Figure 8 In (A), in a structure without a charged film, when the spike 061a of the developer 061 contacts the support 054, the developer 061 is easily separated by the physical force of sliding friction. Therefore, free developer is easily generated. Figure 8 As shown in (B), when the position of the spike 061a is on the downstream side of the support portion 054, there is a non-sliding friction area 062 on the upstream side. Therefore, a part of the free developer stays in the non-sliding friction area 062. Therefore, it is easy to reduce the free developer flowing out to the outside of the developing device.

[0120] exist Figure 8 In (C), in the structure having a charged film 53, when the length of the film support portion 54 is formed in such a way that the range of the fringe 61a becomes approximately the entire area of ​​the film support portion 54, it is easy to utilize the electric field between the charged film 53 and the developing sleeve 52 to recover the free developer.

[0121] exist Figure 8 In (D), when the length of the charged film 53' is extended to a range where the spike 61a does not contact, a non-sliding friction area 62 is generated. In the non-sliding friction area 62, although the voltage is lower than that of the sliding friction area 63 of sliding friction, it is charged. Since the charging polarity of the non-sliding friction area 62 is the same as that of the developer, sometimes a part of the developer of the spike 61a is freed due to the electrostatic reaction force.

[0122] Therefore, it is ideal that the length of the charging film 53 is set to a length corresponding to the width of the sliding friction region 63 so that the non-sliding friction region 62 is reduced.

[0123] In addition, the range of sliding friction of the developer on the charged film 53 varies according to the positions of each magnetic pole S1, N3 and the gap between the charged film 53 and the developing sleeve 52. In addition, the faster the circumferential speed of the developing sleeve 52, the stronger the centrifugal force. Therefore, the developer that is free and suspended in the developing area Q2k tends to increase. In addition, the developer retained on the developing sleeve 52 becomes easy to stand up. Therefore, the faster the circumferential speed of the developing sleeve 52 becomes, the more free the developer increases. In order to improve the recovery performance accordingly, it is preferred to expand the range of sliding friction, and since it becomes easy to stand up and easy to expand the range of sliding friction, it is preferred to expand the range of sliding friction. Therefore, it is preferred that the faster the circumferential speed of the developing sleeve 52 becomes, the longer the length of the charged film 53 is increased.

[0124] The larger the diameter of the developing sleeve 52 is, the faster the peripheral speed is when the rotation speed and angular speed of the motor are the same. Therefore, as described above, it is preferable to increase the length of the charging film 53 as the diameter increases.

[0125] Furthermore, the farther the charged film 53 is from the magnetic poles S1 and N3, the easier it is for the developer to fall over as described above. Therefore, the farther away from the magnetic poles S1 and N3, the more difficult it is for the developer to slide and rub, so it is preferred to shorten the charged film 53 the farther away from the magnetic poles S1 and N3. In other words, it is preferred to lengthen the charged film 53 the closer to the magnetic poles S1 and N3. On the other hand, in the case where the charged film 53 cannot be arranged at a position farther than the magnetic poles S1 and N3, it is preferred to narrow the gap between it and the developing sleeve 52 to facilitate sliding and rubbing, and increase the length of the charged film 53 to improve the recovery performance of the free developer.

[0126] In addition, the weaker the magnetic force of the magnetic poles S1 and N3, the easier it is for the spike to fall. Therefore, similarly to the case where the distance from the magnetic poles S1 and N3 is far, it is preferred that the weaker the magnetic force of the magnetic poles S1 and N3, the shorter the charged film 53 is. In other words, it is preferred that the stronger the magnetic poles S1 and N3 are, the longer the charged film 53 is. In addition, in the case where the magnetic force of the magnetic poles S1 and N3 cannot be increased, it is preferred to narrow the gap between them and the developing sleeve 52 to facilitate sliding friction, and increase the length of the charged film 53 to improve the recovery performance of the free developer.

[0127] (Variation 1 of the embodiment)

[0128] Fig. 9 It is an explanatory diagram of Modification 1 of the embodiment, and is an explanatory diagram when the opposing member is arranged on the upstream side of the developing region.

[0129] exist Fig. 9 In the developing device Gk of the modification 1 of the embodiment, a charging film 153 is arranged between the developing region Q2 k and the dresser 55 on the upstream side of the developing region Q2 k.

[0130] The developer suspended during development in the development region Q2k may also be suspended on the upstream side of the development region Q2k. Therefore, in the first modification of the embodiment, it is possible to suppress image quality degradation and contamination due to free developer on the upstream side of the development region Q2k.

[0131] (Variation 2 of the embodiment)

[0132] Fig.10 It is an explanatory diagram of Modification Example 2 of the embodiment.

[0133] exist Fig.10 In the embodiment, unlike the developing device Gk having only one developing roller R0k, the developing device Gk of the modified example 2 of the embodiment has a first developing roller 201 as an example of a first developer holding unit and a second developing roller 202 as an example of a second developer holding unit. Along the rotation direction of the photosensitive drum Pk, the first developing roller 201 is arranged on the upstream side, and the second developing roller 202 is arranged on the downstream side.

[0134] The developer is supplied from the supply chamber 3 to the first developing roller 201. The first developing roller 201 supplies the developer to the photosensitive drum Pk in the first developing area Q2a opposite to the photosensitive drum Pk. The first developing roller 201 that has passed through the first developing area Q2a receives the developer from the first developing roller 201 to the second developing roller 202 in the handover area 203 opposite to the second developing roller 202. The second developing roller 202 supplies the developer to the photosensitive drum Pk in the second developing area Q2b opposite to the photosensitive drum Pk. The second developing roller 202 that has passed through the second developing area Q2b returns the developer to the return chamber 6.

[0135] In the developing device Gk of the modification 2 of the embodiment, similarly to the modification 1 of the embodiment, a first charged film 153 as an example of a first relative unit is arranged on the upstream side of the first developing area Q2a with respect to the rotation direction of the first developing roller 201. In addition, similarly to the embodiment, a second charged film 53 as an example of a second relative unit is arranged on the downstream side of the second developing area Q2b with respect to the rotation direction of the second developing roller 202.

[0136] Furthermore, a third charged film 204 as an example of a third opposing unit is arranged at a position on the photosensitive drum Pk side relative to the intersection region 203. In the second modification of the embodiment, the third charged film 204 is arranged in a manner facing the first developing roller 201. In addition, it is not limited to the first developing roller 201, and can be arranged in a manner facing the second developing roller 202, and two developing rollers 201 and 202 can also be provided corresponding to the two developing rollers.

[0137] In addition, the length of each charged film 53, 153, 204 is set to a length corresponding to the range of sliding friction of the developer. Therefore, when the diameters of the first developing roller 201 and the second developing roller 202 are different or the peripheral speeds are different, the lengths of each charged film 53, 153, 204 can be set to different lengths.

[0138] Therefore, in the second modification of the embodiment, the developer suspended on the upstream side of the first developing area Q2a can be recovered by the first charged film 153. In addition, the developer suspended on the downstream side of the second developing area Q2b can be recovered by the second charged film 53. Therefore, the free developer can be eliminated at both ends of the opening portion of the developing device Gk relative to the photosensitive drum Pk. Therefore, the adverse effects caused by the free developer can be eliminated.

[0139] Furthermore, in the second variation of the embodiment, a third charged film 204 is also arranged at a position corresponding to the junction area 203. Therefore, the third charged film 204 can be used to recover the free developer generated during the junction in the junction area 203. Therefore, the adverse effects caused by the free developer can be further suppressed. In addition, it is ideal to set the third charged film 204, but it is also possible to set the structure without setting the third charged film 204.

[0140] (Change Example)

[0141] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H05) of the present invention are shown below.

[0142] (H01) In the above embodiment, a copy machine U is illustrated as an example of an image forming apparatus, but the present invention is not limited thereto and can be applied to a FAX and a multifunction machine having multiple functions such as a FAX, a printer, and a copy machine. In addition, the present invention is not limited to a multi-color image forming apparatus and can be configured as a single-color, so-called black-and-white image forming apparatus. Furthermore, the present invention is not limited to an image forming apparatus and can be applied to any electronic equipment or mechanical device using a motor and a gear.

[0143] (H02) In the above embodiment, the intermediate transfer belt B is illustrated as an example of the image holding unit, but the present invention is not limited to this and can also be applied to a photoreceptor, etc. Therefore, the image holding unit is not limited to a belt-shaped member and can also be applied to a drum-shaped member.

[0144] (H03) In the above embodiment, a film-like form is exemplified as the relative unit, but the present invention is not limited thereto. For example, the relative unit may be in any shape such as a solid form (block form). However, in order to miniaturize the developing device Gk, a film (thin film form) is preferred.

[0145] (H04) In the above-mentioned Modifications 1 and 2, it is ideal to provide the charging film 53 on the downstream side, but a structure in which the charging film 53 on the downstream side is not provided may be adopted.

[0146] (H05) In the above-described embodiments, it is desirable to provide the charged films 53, 153, 204, but a structure in which the charged films 53, 153, 204 are not provided may be adopted.

[0147] (Note) (((1)))

[0149] A developing device, characterized by comprising:

[0150] a developer containing unit, wherein the developer containing unit contains developer;

[0151] a developer holding unit, the developer holding unit being supported by the developer containing unit and holding the developer on a surface;

[0152] a first conveying unit for conveying the developer of the developer containing unit, the first conveying unit being arranged in parallel with the developer holding unit and supplying the developer to the developer holding unit;

[0153] a second conveying unit for conveying the developer of the developer storage unit, the second conveying unit being arranged in parallel with the first conveying unit and conveying the developer in a direction opposite to the first conveying unit;

[0154] a third conveying unit for conveying the developer of the developer containing unit, the third conveying unit being arranged in parallel with the second conveying unit and conveying the developer separated from the developer holding unit;

[0155] a first receiving unit for receiving the developer conveyed by the first conveying unit;

[0156] a second receiving unit for receiving the developer conveyed by the second conveying unit;

[0157] a third receiving unit for receiving the developer conveyed by the third conveying unit;

[0158] A first partition unit, the first partition unit is arranged between the first receiving unit and the second receiving unit to separate the first receiving unit from the second receiving unit;

[0159] A second partition unit, the second partition unit is disposed between the second receiving unit and the third receiving unit to separate the second receiving unit from the third receiving unit;

[0160] a first inflow unit, the first inflow unit being disposed on an upstream side of the first partition unit with respect to a conveying direction of the first conveying unit, and allowing the developer to flow from the second containing unit into the first containing unit;

[0161] a second inflow unit disposed on an upstream side of the first partition unit with respect to a conveying direction of the second conveying unit and causing the developer to flow from the first storage unit into the second storage unit; and

[0162] A third inflow unit is disposed on an upstream side of the second partition unit with respect to a conveying direction of the second conveying unit, and causes the developer to flow from the third storage unit into the second storage unit. (((2)))

[0164] The developing device according to (((1))) is characterized in that:

[0165] With respect to the conveying direction of the second conveying unit, the downstream end of the third inflow unit is arranged on the upstream side compared with the downstream end of the second inflow unit. (((3)))

[0167] The developing device according to (((1))) is characterized in that:

[0168] The third inflow unit is arranged at an upstream portion of an inflow range of the second inflow unit with respect to a conveying direction of the second conveying unit. (((4)))

[0170] The developing device according to (((1))) is characterized in that:

[0171] The third inflow unit does not overlap at a downstream portion of an inflow range of the second inflow unit with respect to a conveying direction of the second conveying unit. (((5)))

[0173] The developing device according to any one of (((1))) to (((4))), characterized in that:

[0174] A fourth inflow unit is provided into which the developer replenished to the developer storage unit flows, and the fourth inflow unit is arranged at a position corresponding to the third inflow unit. (((6)))

[0176] The developing device according to any one of (((1))) to (((4))), characterized in that:

[0177] A fourth inflow unit is provided for inflow of the developer to be replenished to the developer storage unit,

[0178] The downstream end of the fourth inflow unit is arranged on the upstream side compared to the downstream end of the second inflow unit. (((7)))

[0180] An image forming device, characterized in that it comprises:

[0181] Image holding unit;

[0182] The developing device described in any one of (((1))) to (((6))) develops the image of the image holding unit;

[0183] a transfer unit that transfers the image developed by the developing device from the image holding unit to a medium; and

[0184] A fixing unit fixes the image transferred onto the medium.

[0185] According to the developing device of (((1))), in a developing device that circulates a developer by using a first conveying unit and a second conveying unit, in a structure in which a developer separated from a developer holding unit is conveyed by a third conveying unit, short circuit of the separated developer to the second conveying unit can be suppressed compared to a case in which a developer containing unit of the third conveying unit and a developer containing unit of the second conveying unit are not separated.

[0186] According to the developing device of (((2))), compared with a case where the downstream end of the third inflow unit is not arranged upstream of the downstream end of the second inflow unit, it is possible to suppress the developer from flowing back to the third inflow unit.

[0187] According to the developing device of (((3))), compared with a case where the third inflow unit is not arranged at the upstream portion of the inflow range of the second inflow unit, it is possible to suppress the developer from flowing back to the third inflow unit.

[0188] According to the developing device of (((4))), compared with a case where the downstream portion of the inflow range of the third inflow unit overlaps with that of the second inflow unit, it is possible to suppress the developer from flowing back to the third inflow unit.

[0189] According to the developing device of (((5))), it is possible to mix the low-concentration developer from the third inflow unit and the new insufficiently charged developer from the fourth inflow unit. Therefore, compared with the case where the fourth inflow unit is not arranged at a position corresponding to the third inflow unit, it is possible to suppress uneven concentration of the developer.

[0190] According to the developing device of (((6))), it is possible to mix the low-concentration developer from the third inflow unit and the new insufficiently charged developer from the fourth inflow unit. Therefore, compared with a case where the downstream end of the fourth inflow unit is not arranged on the upstream side of the downstream end of the second inflow unit, it is possible to suppress uneven concentration of the developer.

[0191] According to the image forming device of (((7))), in a developing device that circulates a developer using a first conveying unit and a second conveying unit, in a structure in which a developer separated from a developer holding unit is conveyed using a third conveying unit, short circuit of the separated developer to the second conveying unit can be suppressed compared to a case in which the developer containing unit of the third conveying unit and the developer containing unit of the second conveying unit are not separated.

Claims

1. A developing device, characterized in that: have: a developer containing unit, wherein the developer containing unit contains developer; a developer holding unit, the developer holding unit being supported by the developer containing unit and holding the developer on a surface; a first conveying unit for conveying the developer of the developer containing unit, the first conveying unit being arranged in parallel with the developer holding unit and supplying the developer to the developer holding unit; a second conveying unit for conveying the developer of the developer storage unit, the second conveying unit being arranged in parallel with the first conveying unit and conveying the developer in a direction opposite to the first conveying unit; a third conveying unit for conveying the developer of the developer containing unit, the third conveying unit being arranged in parallel with the second conveying unit and conveying the developer separated from the developer holding unit; a first receiving unit for receiving the developer conveyed by the first conveying unit; a second receiving unit for receiving the developer conveyed by the second conveying unit; a third receiving unit for receiving the developer conveyed by the third conveying unit; A first partition unit, the first partition unit is arranged between the first receiving unit and the second receiving unit to separate the first receiving unit from the second receiving unit; A second partition unit, the second partition unit is disposed between the second receiving unit and the third receiving unit to separate the second receiving unit from the third receiving unit; a first inflow unit, the first inflow unit being disposed on an upstream side of the first partition unit with respect to a conveying direction of the first conveying unit, and allowing the developer to flow from the second containing unit into the first containing unit; a second inflow unit, the second inflow unit being arranged on an upstream side of the first partition unit with respect to a conveying direction of the second conveying unit, and allowing the developer to flow from the first storage unit into the second storage unit; as well as A third inflow unit is disposed on an upstream side of the second partition unit with respect to a conveying direction of the second conveying unit, and causes the developer to flow from the third storage unit into the second storage unit.

2. The developing device according to claim 1, wherein: With respect to the conveying direction of the second conveying unit, the downstream end of the third inflow unit is arranged on the upstream side compared with the downstream end of the second inflow unit.

3. The developing device according to claim 1, wherein: The third inflow unit is arranged at an upstream portion of an inflow range of the second inflow unit with respect to a conveying direction of the second conveying unit.

4. The developing device according to claim 1, wherein: The third inflow unit does not overlap at a downstream portion of an inflow range of the second inflow unit with respect to a conveying direction of the second conveying unit.

5. The developing device according to any one of claims 1 to 4, wherein: A fourth inflow unit is provided into which the developer replenished to the developer storage unit flows, and the fourth inflow unit is arranged at a position corresponding to the third inflow unit.

6. The developing device according to any one of claims 1 to 4, wherein: A fourth inflow unit is provided for inflow of the developer to be replenished to the developer storage unit, The downstream end of the fourth inflow unit is arranged on the upstream side compared to the downstream end of the second inflow unit.

7. An image forming device, characterized in that: have: Image holding unit; The developing device according to any one of claims 1 to 6, which develops the image of the image holding unit; a transfer unit that transfers the image developed by the developing device from the image holding unit to a medium; as well as A fixing unit fixes the image transferred onto the medium.

Images