Developing device and image forming apparatus

Abstract

To reduce separation of developer while preventing an increase in the number of components, compared with a case where a voltage application device attracting separated developer is provided.SOLUTION: A developing device (Gk) comprises opposing means (53) that is arranged opposite to developer holding means (R0k), the opposing means (53) arranged at a position where it is rubbed with developer (61a) moving along with the rotation of the developer holding means (R0k) and formed of a material having a charging ability with the same polarity as that of the developer (61a).SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] 2. Description of the Related Art In an image forming apparatus that electrostatically transfers and fixes a developer image on an image holding means onto a medium such as paper to form an image, the technique described in Patent Document 1 below is known.

[0003] Patent Document 1 describes a configuration in which a first shielding plate (11) and a second shielding plate (12) are disposed upstream and downstream in the rotation direction of the opposing region between the photoconductor (2) and the developing sleeve (5). In Patent Document 1, a voltage is applied to the first shielding plate (11) and the second shielding plate (12) to electrically return freed and scattered charged toner to the developing sleeve (5). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-255700 A ("0012" to "0021", Figs. 1 and 3) Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has a technical object to suppress the liberation of developer while suppressing an increase in the number of parts, as compared to the case where a voltage application device that attracts the liberated developer is provided. [Means for solving the problem]

[0006] In order to solve the above technical problem, the developing device of the invention described in claim 1 is: a developer holding means that holds a magnetic developer on its surface by magnetic force and rotates; an opposing means disposed opposite to the developer holding means, the opposing means being disposed at a position where the developer moving with the rotation of the developer holding means is rubbed against the opposing means, the opposing means being made of a material having a charging ability of the same polarity as the developer; The present invention is characterized by comprising:

[0007] The invention described in claim 2 is the developing device described in claim 1, a developing area in which an image holding means for holding an image on its surface faces the developer holding means, the developing means being disposed downstream of the image holding means; The present invention is characterized by comprising:

[0008] The invention described in claim 3 is the developing device described in claim 1, a developer holding means for holding an image on a surface of the developer holding means, the developer holding means being disposed upstream of the developer holding means; The present invention is characterized by comprising:

[0009] The invention described in claim 4 is the developing device described in claim 1, The length of the opposing means along the rotation direction of the image holding means holding the image on its surface corresponds to the width of the developer being rubbed. It is characterized by:

[0010] The invention described in claim 5 is the developing device described in claim 4, a developer accommodating means for accommodating a developer therein, the developer accommodating means rotatably supporting the developer holding means and supporting the opposing means; Equipped with The length of the portion supporting the opposing means corresponds to the length of the opposing means. It is characterized by:

[0011] The invention as set forth in claim 6 is the developing device as set forth in claim 4, the opposing means being formed longer as the peripheral speed of the developer holding means increases; The present invention is characterized by comprising:

[0012] The invention described in claim 7 is the developing device described in claim 4, the opposing means being formed longer as the diameter of the developer holding means becomes longer; The present invention is characterized by comprising:

[0013] The invention described in claim 8 is the developing device described in claim 4, the closer the position of the facing means is to the position of the magnetic pole provided on the developer holding means, the longer the facing means is formed; The present invention is characterized by comprising:

[0014] The invention as set forth in claim 9 is the developing device as set forth in claim 4, the opposing means being formed longer as the magnetic force of the magnetic pole provided in the developer holding means becomes stronger; The present invention is characterized by comprising:

[0015] The invention described in claim 10 is the developing device described in claim 1, a developer holding means having a first developer holding means disposed opposite an image holding means that holds an image on its surface, and a second developer holding means disposed opposite the image holding means downstream of the first developer holding means along the rotation direction of the image holding means and disposed opposite the image holding means; the opposing means including a first opposing means arranged upstream of a position where the first developer holding means and the image holding means face each other with respect to a rotation direction of the first developer holding means, and a second opposing means arranged downstream of a position where the second developer holding means and the image holding means face each other with respect to a rotation direction of the second developer holding means; The present invention is characterized by comprising:

[0016] The invention described in claim 11 is the developing device described in claim 10, the opposing means having a third opposing means disposed at a position on the image holding means side with respect to an opposing position between the first developer holding means and the second developer holding means; The present invention is characterized by comprising:

[0017] The invention described in claim 12 is the developing device described in claim 10, the first opposing means and the second opposing means having lengths corresponding to the peripheral speeds of the first developer holding means and the second developer holding means, respectively; The present invention is characterized by comprising:

[0018] In order to solve the above technical problem, the image forming apparatus according to the invention described in claim 13 comprises: An image holding means; a developing device according to any one of claims 1 to 12, which develops the image on the image holding means; a transfer means for transferring the image developed by the developing device from the image holding means to a medium; a fixing device for fixing the image transferred to the medium; The present invention is characterized by comprising: Effect of the Invention

[0019] According to the invention as set forth in claims 1 and 13, it is possible to suppress the liberation of developer while suppressing an increase in the number of parts, as compared to the case where a voltage application device that attracts the liberated developer is provided. According to the invention as set forth in claim 2, adhesion of free developer to the image holding means after development is suppressed, and deterioration of image quality is suppressed. According to the invention as set forth in claim 3, adhesion of free developer to the image holding means before development is suppressed, and deterioration of image quality is suppressed. According to the invention as set forth in claim 4, it is possible to suppress the developer from becoming detached due to the electric field in the non-rubbing region, compared to a case in which the length of the facing means is longer than the width of the developer rubbed against the facing means.

[0020] According to the invention as set forth in claim 5, it is possible to suppress the liberation of the developer while suppressing an increase in size of the developing container, as compared to a case in which the length of the portion supporting the opposing means is longer than the opposing means. According to the invention as set forth in claim 6, the faster the circumferential speed of the developer holding means is, the more the free developer recovery capability can be improved compared to a case in which the opposing means is not made longer. According to the seventh aspect of the invention, the longer the diameter of the developer holding means, the more improved the recovery capability of the free developer can be compared to a case where the opposing means is not made longer. According to the invention as recited in claim 8, the closer the position of the opposing means is to the position of the magnetic pole of the developer holding means, the more improved the recovery capability of the free developer can be compared to a case in which the opposing means is not long.

[0021] According to the ninth aspect of the present invention, the stronger the magnetic force of the magnetic pole of the developer holding means, the more improved the recovery capability of the free developer can be compared to a case in which the opposing means is not long. According to the invention described in claim 10, free developer can be collected on the upstream side of the first developer holding means and the downstream side of the second developer holding means. Therefore, free developer can be suppressed at the most upstream position and the most downstream position facing the image holding means. According to the invention described in claim 11, it is possible to suppress the release of developer, compared to a case in which the third opposing means is not disposed in the opposing region between the first developer holding means and the second developer holding means. According to the invention as set forth in claim 12, even if there is a difference in peripheral speed between the first developer holding means and the second developer holding means, the opposing means according to the peripheral speed can suppress the release of the developer. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is an overall explanatory diagram of an image forming apparatus according to a first embodiment. [Diagram 2] FIG. 2 is an enlarged explanatory view of the visible image forming device of the first embodiment. [Diagram 3] FIG. 3 is an explanatory diagram of the developing device according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6]6A and 6B are explanatory diagrams of the flow of developer in a developing device, in which FIG. 6A is an explanatory diagram of the flow of developer in a conventional configuration, and FIG. 6B is an explanatory diagram of the flow of developer in the first embodiment. [Figure 7] FIG. 7 is an enlarged view of the opposing means of the first embodiment. [Figure 8] FIG. 8A is an explanatory diagram of a conventional configuration in which an opposing member is not provided and the length of the support part is approximately the same as the sliding range, FIG. 8B is an explanatory diagram of a conventional configuration in which an opposing member is not provided and the length of the support part is longer than the sliding range, FIG. 8C is an explanatory diagram of an example of the present invention in which an opposing member is provided and the length of the support part is approximately the same as the sliding range, and FIG. 8D is an explanatory diagram of another form of the present invention in which an opposing member is provided and the length of the support part is longer than the sliding range. [Figure 9] FIG. 9 is an explanatory diagram of a first modified example of the first embodiment, in which an opposing member is disposed on the upstream side of the development area. [Figure 10] FIG. 10 is an explanatory diagram of a second modified example of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Next, specific examples of the present invention (hereinafter, referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples. In order to make the following explanation easier to understand, in the drawings, the front-to-back direction is the X-axis direction, the left-to-right direction is the Y-axis direction, and the up-down direction is the Z-axis direction, and the directions or sides indicated by arrows X, -X, Y, -Y, Z, and -Z are respectively the front, rear, right, left, upper, and lower, or the front side, rear side, right side, left side, upper side, and lower side. In addition, in the figures, a "·" inside a "○" means an arrow going from the back to the front of the page, and an "×" inside a "○" means an arrow going from the front to the back of the page. In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate to facilitate understanding. EXAMPLES

[0024] FIG. 1 is an overall explanatory diagram of an image forming apparatus according to a first embodiment. FIG. 2 is an enlarged explanatory view of the visible image forming device of the first embodiment. In Figure 1, a copier U as an example of an image forming device has a user interface UI as an example of an operation unit, a scanner unit U1 as an example of an image reading device, a feeder unit U2 as an example of a media supply device, an image creating unit U3 as an example of an image recording device, and a media processing device U4.

[0025] (User Interface UI Description) The user interface UI has an input button UIa used to start copying, set the number of copies, etc. The user interface UI also has a display unit UIb on which the contents input by the input button UIa and the status of the copier U are displayed.

[0026] (Explanation of Feeder Section U2) 1, the feeder unit U2 has a plurality of paper feed trays TR1, TR2, TR3, and TR4 as an example of a medium storage container. The feeder unit U2 also has a medium supply path SH1 that takes out recording paper S as an example of an image recording medium stored in each of the paper feed trays TR1 to TR4 and transports it to the imaging unit U3.

[0027] (Explanation of the imaging unit U3 and media processing device U4) In FIG. 1, the image forming unit U3 has an image recording unit U3a that records an image on the recording paper S conveyed from the feeder unit U2 based on an original image read by the scanner unit U1. 1 and 2, a driving circuit D of the latent image forming device of the imaging unit U3 outputs corresponding driving signals to latent image forming devices ROSy, ROSm, ROSc, and ROSk of yellow (Y), magenta (M), cyan (C), and black (K) at preset times based on image information input from the scanner unit U1. Photoconductor drums Py, Pm, Pc, and Pk as an example of image holding means are arranged below each of the latent image forming devices ROSy to ROSk as an example of writing means.

[0028] The surfaces of the rotating photoconductor drums Py to Pk are uniformly charged by charging rolls CRy, CRm, CRc, and CRk, which are an example of a charging means, respectively. Electrostatic latent images are formed on the charged surfaces of the photoconductor drums Py to Pk by laser beams Ly, Lm, Lc, and Lk, which are an example of latent image writing light outputted from the latent image forming devices ROSy to ROSk. The electrostatic latent images on the surfaces of the photoconductor drums Py to Pk are developed into toner images, which are an example of visible images, of yellow (Y), magenta (M), cyan (C), and black (K), by developing devices Gy, Gm, Gc, and Gk, which are an example of a developing means. In the developing devices Gy to Gk, the developer consumed by development is replenished from toner cartridges Ky, Km, Kc, and Kk, which are an example of a developer storage means. The toner cartridges Ky to Kk are detachably mounted in the developer replenishing device U3b.

[0029] The toner images on the surfaces of the photoconductor drums Py to Pk are transferred in a sequentially overlapping manner in primary transfer areas Q3y, Q3m, Q3c, and Q3k onto an intermediate transfer belt B as an example of an intermediate transfer means by primary transfer rolls T1y, T1m, T1c, and T1k as an example of a primary transfer device, and a color toner image as an example of a multi-color visible image is formed on the intermediate transfer belt B. The color toner image formed on the intermediate transfer belt B is transported to a secondary transfer area Q4. When only K-color image information is present, only the K-color photoconductor drum Pk and the developing device Gk are used, and only the K-color toner image is formed. After the primary transfer, residual developer, paper powder, and other residues adhering to the surfaces of the photoconductor drums Py to Pk are removed by drum cleaners CLy, CLm, CLc, and CLk, which are an example of a cleaning means for an image holding means.

[0030] In the first embodiment, the photoconductor drum Pk, the charging roll CRk, and the drum cleaner CLk are integrated as a photoconductor unit UK for the color K, which is an example of an image carrier unit. Similarly, for the other colors Y, M, and C, the photoconductor drums Py, Pm, and Pc, the charging rolls CRy, CRm, and CRc, and the drum cleaners CLy, CLm, and CLc constitute photoconductor units UY, UM, and UC. Furthermore, the K-color photoconductor unit UK and the developing device Gk having the developing roll R0k as an example of the developer holding device constitute the K-color image forming means UK+Gk. Similarly, the Y-, M-, and C-color photoconductor units UY, UM, and UC and the developing devices Gy, Gm, and Gc having the developing rolls R0y, R0m, and R0c constitute the Y-, M-, and C-color image forming means UY+Gy, UM+Gm, and UC+Gc, respectively.

[0031] A belt module BM as an example of an intermediate transfer unit is disposed below the photoconductor drums Py-Pk. The belt module BM has an intermediate transfer belt B as an example of an image holding means, a drive roll Rd as an example of a drive means for the intermediate transfer means, a tension roll Rt as an example of a tension applying means, a walking roll Rw as an example of a meandering prevention means, a plurality of idler rolls Rf as an example of a driven means, a backup roll T2a as an example of an opposing means, and the primary transfer rolls T1y-T1k. The intermediate transfer belt B is supported so as to be rotatable in the direction of the arrow Ya. In the first embodiment, the primary transfer rolls T1y, T1m, and T1c for Y, M, and C colors are supported so as to be able to approach and move away from the photoconductor drums Py, Pm, and Pc. In the case of multi-color printing (color printing), the primary transfer rolls T1y, T1m, and T1c for Y, M, and C colors approach the photoconductor drums Py to Pc and pinch the intermediate transfer belt B with a predetermined contact pressure. On the other hand, in the case of single-color printing (monochrome printing) using only black, they move away from the photoconductor drums Py to Pc.

[0032] A secondary transfer unit Ut is disposed below the backup roll T2a. The secondary transfer unit Ut has a secondary transfer roll T2b as an example of a secondary transfer member. A secondary transfer area Q4 is formed by an area where the secondary transfer roll T2b contacts the intermediate transfer belt B. A backup roll T2a faces the secondary transfer roll T2b with the intermediate transfer belt B sandwiched therebetween. A contact roll T2c as an example of a power supply means contacts the backup roll T2a. A secondary transfer voltage having the same polarity as the charging polarity of the toner is applied to the contact roll T2c. The backup roll T2a, the secondary transfer roll T2b, and the contact roll T2c constitute a secondary transfer unit T2, which is an example of a secondary transfer means.

[0033] The secondary transfer unit Ut in the first embodiment is configured to be movable toward and away from the intermediate transfer belt B. The secondary transfer unit Ut moves depending on the type of recording paper S being used to change the contact pressure between the secondary transfer roll T2b and the intermediate transfer belt B. For example, when thick paper is used, the contact pressure can be weakened compared to when plain paper is used, thereby mitigating the impact when the leading edge of the thick paper enters the secondary transfer area Q4.

[0034] A medium transport path SH2 is disposed below the belt module BM. The recording paper S fed from the medium supply path SH1 of the feeder unit U2 is transported by a transport roll Ra, which is an example of a medium transport means, to a registration roll Rr, which is an example of a transport timing adjustment means. The registration roll Rr transports the recording paper S downstream in accordance with the timing at which the toner image formed on the intermediate transfer belt B is transported to the secondary transfer area Q4. The recording paper S sent out by the registration roll Rr is guided by a registration side paper guide SGr and a pre-transfer paper guide SG1, and transported to the secondary transfer area Q4. The toner image on the intermediate transfer belt B is transferred to the recording paper S by the secondary transfer device T2 as it passes through the secondary transfer area Q4. In the case of a color toner image, the toner images that are primarily transferred onto the surface of the intermediate transfer belt B in a superimposed manner are secondarily transferred to the recording paper S all at once. The primary transfer rolls T1y to T1k, the secondary transfer unit T2, and the intermediate transfer belt B constitute transfer devices T1y to T1k+T2+B as an example of a transfer means.

[0035] After the secondary transfer, the intermediate transfer belt B is cleaned by a belt cleaner CLB, which is an example of a cleaning means for the intermediate transfer means and is disposed downstream of the secondary transfer area Q4. The belt cleaner CLB removes residual matter such as developer and paper powder that has not been transferred from the intermediate transfer belt B in the secondary transfer area Q4.

[0036] The recording paper S onto which the toner image has been transferred is guided by a post-transfer paper guide SG2 and sent to a belt conveying device BH, which is an example of a medium conveying means. The belt conveying device BH conveys the recording paper S to a fixing device F. The fixing device F, which is an example of a fixing means, has a heating roll Fh, which is an example of a heating means, and a pressure roll Fp, which is an example of a pressure means. The recording paper S is transported to a fixing area Q5, which is an area where the heating roll Fh and the pressure roll Fp come into contact with each other. When the toner image on the recording paper S passes through the fixing area Q5, the toner image is heated and pressed by the fixing device F, and is fixed. The image forming means UY+Gy-UK+Gk, the transfer devices T1y-T1k+T2+B, and the fixing device F constitute an image recording unit U3a as an example of the image forming means in the first embodiment.

[0037] A switching gate GT1, which is an example of a switching means, is provided downstream of the fixing device F. The switching gate GT1 selectively switches the recording paper S that has passed through the fixing area Q5 to either the discharge path SH3 or the reversal path SH4 on the media processing device U4 side. The recording paper S transported to the discharge path SH3 is transported to the paper transport path SH5 of the media processing device U4. A curl correction member U4a, which is an example of a warp correction means, is disposed on the paper transport path SH5. The curl correction member U4a corrects the warp, or so-called curl, of the recording paper S that has been brought in. The recording paper S, whose curl has been corrected, is discharged by discharge rolls Rh, which are an example of a medium discharge member, to a discharge tray TH1, which is an example of a medium discharge section, with the image fixing surface of the paper facing upward.

[0038] The recording paper S conveyed to the reverse path SH4 side of the image forming unit U3 by the switching gate GT1 passes through a second gate GT2, which is an example of a switching means, and is conveyed to the reverse path SH4 of the image forming unit U3. At this time, when the recording paper S is discharged with the image fixing surface facing downward, the conveying direction of the recording paper S is reversed after the trailing end of the recording paper S in the conveying direction passes through the second gate GT2. Here, the second gate GT2 in the first embodiment is made of a thin-film elastic member. Therefore, the second gate GT2 passes the recording paper S conveyed to the reversing path SH4 once as it is, and when the recording paper S that has passed through is reversed, that is, switched back, it is guided to the conveying paths SH3 and SH5. Then, the switched back 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.

[0039] A circulation path SH6 is connected to the inversion path SH4 of the imaging unit U3, and a third gate GT3 as an example of a switching means is disposed at the connection point between them. The downstream end of the inversion path SH4 is connected to an inversion path SH7 of the media processing device U4. The recording paper S transported to the reverse path SH4 through the switching gate GT1 is transported to the reverse path SH7 side of the media processing device U4 by the third gate GT3. The third gate GT3 in the first embodiment is made of a thin elastic material, similar to the second gate GT2. Therefore, the third gate GT3 allows the recording paper S transported along the reverse path SH4 to pass through once, and when the recording paper S that has passed through is switched back, it is guided to the circulation path SH6 side.

[0040] The recording paper S transported to the circulation path SH6 is sent again to the secondary transfer area Q4 via the medium transport path SH2, where the second side is printed. The elements denoted by the reference characters SH1 to SH7 constitute the sheet transport path SH. The elements denoted by the reference characters SH, Ra, Rr, Rh, SGr, SG1, SG2, BH, and GT1 to GT3 constitute the sheet transport device SU of the first embodiment.

[0041] (Description of the developing device) FIG. 3 is an explanatory diagram of the developing device according to the first embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. In the following description, since the Y, M, C, and K developing devices Gy to Gk are configured in the same manner, only the K developing device Gk will be described, and descriptions of the other color developing devices Gy, Gm, and Gc will be omitted. 3 to 5, the developing devices Gy to Gk as an example of a developing means have a developing container 1 as an example of a container. In the first embodiment, the developing container 1 contains a two-component developer made of a negatively charged toner and a positively charged magnetic carrier.

[0042] A developing chamber 2 in which the developing roll R0k is accommodated is formed inside the developing container 1. The developing chamber 2 extends along the axial direction of the developing roll R0k. A supply chamber 3, which is an example of a first accommodation means, is formed adjacent to and parallel to the right of the developing chamber 2. In Fig. 4, a discharge chamber 3a extending rearward is formed at the rear end of the supply chamber 3. A discharge port 3b, which is an example of a discharge means, is formed at the bottom surface of the rear end of the discharge chamber 3a. A supply port 3c, which is an example of a fourth inflow means, is formed at the top surface of the front end of the supply chamber 3. New developer is replenished from the toner cartridge Kk to the supply port 3c.

[0043] 3 to 5, a stirring chamber 4 as an example of a second storage means is formed adjacent to and parallel to the supply chamber 3. A return chamber 6 as an example of a third storage means is formed adjacent to and parallel to the development chamber 2 and the stirring chamber 4. The development chamber 2, the supply chamber 3, the stirring chamber 4, and the return chamber 6 store a developer.

[0044] In FIG. 3 and FIG. 4, the developing chamber 2 and the supply chamber 3 are connected over the entire axial direction of the developing roll R0k. That is, no partition means for preventing 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 means. A first inflow section 12 as an example of a first inflow section is formed on the rear end side of the first partition wall 11. A second inflow section 13 as an example of a second inflow section is formed on the front end side of the first partition wall 11. The developer can flow between the supply chamber 3 and the stirring chamber 4 through the first inflow section 12 and the second inflow section 13.

[0045] In FIG. 3 and FIG. 5, the stirring chamber 4 and the return chamber 6 are separated by a second partition wall 16 as an example of a second partition means. A third inflow section 17 as an example of a third inflow section is formed on the front end side of the second partition wall 16. No inflow section is provided on the rear end side of the second partition wall 16. Therefore, the developer can flow between the stirring chamber 4 and the return chamber 6 through the third inflow section 17. In addition, in the first embodiment, the developing chamber 2 and the return chamber 6 are connected over the entire axial area of ​​the developing roll R0k. Therefore, the developer can flow between the developing chamber 2 and the return chamber 6 over the entire axial area.

[0046] A supply auger 21 as an example of a first transport means 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. One outer end of the first rotating shaft 22 supports a first gear G1 as an example of a driven means. A first main transport blade 23, which is an example of a main transport section, is supported on the first rotating shaft 22. In the first embodiment, the first main transport blade 23 is configured as a spiral blade with a predetermined winding direction. The first main transport blade 23 transports the developer in the supply chamber 3 from the rear to the front when the first rotating shaft 22 rotates. That is, the first main transport blade 23 transports the developer from the first inlet section 12 to the second inlet section 13.

[0047] A first reverse transport blade 24 is supported on the front end of the first rotating shaft 22 at a position forward of the first main transport blade 23. The first reverse transport blade 24 is configured as a spiral blade wound in the opposite direction to the first main transport blade 23. Therefore, when the first rotating shaft 22 rotates, the first reverse transport blade 24 transports the developer in the supply chamber 3 backward. The first reverse transport blade 24 applies a reverse transport force to the developer transported forward by the first main transport blade 23, suppressing the forward movement of the developer and promoting the inflow of the developer into the mixing chamber 4 through the second inflow section 13.

[0048] A first sub-transport blade 26 is supported at the rear of the first rotating shaft 22 at a position rearward of the first main transport blade 23. The first sub-transport blade 26 is formed with a spiral having the same winding direction as the first main transport blade 23 and a spiral pitch (the distance traveled in the axial direction during one rotation in the circumferential direction of the first rotating shaft 22) smaller than that of the first main transport blade 23. Therefore, when the first rotating shaft 22 rotates, the first sub-transport blade 26 transports the developer in the supply chamber 3 forward with a transport force weaker than that of the first main transport blade 23. Therefore, a part of the developer that has flowed into the supply chamber 3 through the first inflow portion 12 flows over the first main transport blade 23 and into the discharge chamber 3a at the rear.

[0049] A discharge conveying blade 27 is supported on the rear end of the first rotating shaft 22 at a position rearward of the first sub-conveying blade 26. The discharge conveying blade 27 is configured as a spiral blade wound in the opposite direction to the winding direction 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, particularly in the discharge chamber 3a, toward the discharge port 3b at the rear.

[0050] The stirring chamber 4 accommodates a stirring auger 31 as an example of a second transport means. 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. One outer end of the second rotating shaft 32 supports a second gear G2 as an example of a driven means. In the first embodiment, the second gear G2 meshes with the first gear G1. A second main transport blade 33, which is an example of a main transport section, is supported on the second rotating shaft 32. In the first embodiment, the second main transport blade 33 is configured as a spiral blade with the same winding direction as the first main transport blade 23. The second main transport blade 33 transports the developer in the mixing chamber 4 from the front to the rear when the second rotating shaft 32 rotates. That is, the second main transport blade 33 transports the developer from the second inlet section 13 to the first inlet section 12.

[0051] The return chamber 6 accommodates a return auger 41 as an example of a third transport means. 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. One outer end of the third rotating shaft 42 supports a third gear G3 as an example of a driven means. In the first embodiment, the third gear G3 meshes with the second gear G2. A third main transport blade 43, which is an example of a main transport section, is supported on the third rotating shaft 42. In the first embodiment, the third main transport blade 43 is configured as a spiral blade with the same winding direction as the first main transport blade 23. The third main transport blade 43 transports the developer in the return chamber 6 from the rear to the front when the third rotating shaft 42 rotates. That is, the third main transport blade 43 transports the developer in the return chamber 6 toward the second inlet section 13.

[0052] A third reverse transport blade 44 is supported on the front end of the third rotating shaft 42 at a position forward of the third main transport blade 43. The third reverse transport blade 44 is configured as a spiral blade wound in the opposite direction to the third main transport blade 43. Therefore, when the third rotating shaft 42 rotates, the third reverse transport blade 44 exerts a force to transport the developer in the return chamber 6 backward. The third reverse transport blade 44 exerts a transport force in the opposite direction on the developer transported forward by the third main transport blade 43, suppressing the forward movement of the developer and promoting the inflow of the developer into the mixing chamber 4 through the third inflow portion 17.

[0053] Therefore, the developer in the developing container 1, that is, the developer in the stirring chamber 4 is transported rearward while being stirred by the rotation of the stirring auger 31. The developer transported to the rear end of the stirring chamber 4 flows into the supply chamber 3 through the first inflow portion 12. The developer in the supply chamber 3 is transported from rear to front while being stirred 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 roll R0k. The developer transported to the front end of the supply chamber 3 flows into the stirring chamber 4 through the second inflow portion 13. Therefore, the developer circulates between the supply chamber 3 and the stirring chamber 4. The developer that has been supplied to the developing roll R0k but has not been used in 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 flows into the mixing chamber 4 through the third inlet portion 17. Therefore, the developer returned from the developing roll R0k is also circulated and reused.

[0054] When the developer is consumed during development, new developer is supplied through the supply port 3c. The new developer supplied through the supply port 3c flows into the mixing chamber 4 through the second inlet portion 13 from the front end of the supply chamber 3. Then, the new developer is transported in the mixing chamber 4 while being stirred by the stirring auger 31, and is used for development. A part of the developer that has flowed into the discharge chamber 3a is discharged from the discharge port 3b. In this way, by discharging the developer in the developing container 1 little by little from the discharge port 3b while replenishing new developer from the replenishing port 3c, it is possible to replace deteriorated developer little by little.

[0055] In the first embodiment, the front end of the second partition wall 16 is disposed forward of the front end of the first partition wall 11. Therefore, the width (inflow range) L2 of the second inlet portion 13 is formed larger than the width (inflow range) L3 of the third inlet portion 17. In other words, the downstream end (rear end) of the third inlet portion 17 is disposed upstream (front) of the downstream end (rear end) of the second inlet portion 13 with respect to the developer transport direction of the stirring auger 31. It can also be said that the third inlet portion 17 is disposed in the upstream part (front part) of the inlet range L2 of the second inlet portion 13 with respect to the developer transport direction of the stirring auger 31. That is, the third inlet portion 17 does not overlap the downstream part of the inlet range L2 of the second inlet portion 13 with respect to the developer transport direction of the stirring auger 31.

[0056] In addition, in the first embodiment, the supply port 3c is disposed at a position corresponding to the third inlet portion 17 in the front-rear direction, i.e., in the developer transport direction of the supply auger 21 and the mixing auger 31. In the first embodiment, the supply port 3c is formed to have a narrower width L4 than the third inlet portion 17. Therefore, the supply port 3c is disposed at a position overlapping the third inlet portion 17. Therefore, with respect to the developer transport direction of the mixing auger 31, the downstream end (rear end) of the supply port 3c is disposed on the upstream side (front side) than the downstream end (rear end) of the second inlet portion 13.

[0057] 6A and 6B are explanatory diagrams of the flow of developer in a developing device, in which FIG. 6A is an explanatory diagram of the flow of developer in a conventional configuration, and FIG. 6B is an explanatory diagram of the flow of developer in the first embodiment. In FIG. 6A, in the conventional developing container 01, the return chamber 06 and the stirring chamber 04 were not separated. Therefore, the developer returned from the developing roll to the return chamber 06 was sequentially returned to the stirring chamber 04 at the position where it was returned in the axial direction of the developing roll. Therefore, the developer returned to the return chamber 06 near the first inlet 012 is immediately transported from the stirring chamber 04 to the first inlet 012 and is likely to be reused by the developing roll. Therefore, the developer is likely to deteriorate. On the other hand, it takes time for the developer returned to a position away from the first inlet 012 to be reused by the developing roll. Therefore, unevenness in the deterioration of the developer is likely to occur. In other words, if there is a large amount of developer transported so as to short-circuit near the first inlet 012, deterioration is likely to progress and unevenness is likely to increase. If the unevenness in the deterioration of the developer is large, it can also cause a decrease in image quality.

[0058] In contrast to these, in the developing device Gk of the first embodiment, the return chamber 6 and the stirring chamber 4 are separated by a second partition wall 16. Therefore, as shown in FIG. 6B, all of the developer returned from the developing roll R0k to the return chamber 6 is returned to the stirring chamber 4 from the third inlet portion 17. Therefore, compared to the conventional configuration, short-circuiting of the developer is suppressed. Therefore, uneven deterioration of the developer is suppressed, and deterioration of image quality is also suppressed.

[0059] In addition, in the conventional configuration, the amount of developer returned from the return chamber 06 is greater than the amount of developer circulating in the stirring chamber 04. Therefore, the developer may flow back from the stirring chamber 04 to the return chamber 06. When the backflow occurs, the return chamber 06 may become full of developer, or the developer may be prevented from flowing from the return chamber 06 to the stirring chamber 04. When the return chamber 06 becomes full of developer, it becomes difficult for the developer to return from the developing roll to the return chamber 06. In this case, the developer that has once detached from the developing roll reattaches, and the developer that is insufficiently stirred and insufficiently charged is reused as it is. When an insufficiently charged developer is used, problems such as a decrease in image quality and an increase in free developer may occur.

[0060] In contrast, in the first embodiment, the third inlet portion 17 is disposed in the upstream portion (front portion) of the inlet range L2 of the second inlet portion 13 with respect to the developer transport direction of the stirring auger 31. Therefore, most of the developer flowing from the supply chamber 3 into the stirring chamber 4 flows in behind the second inlet portion 13. Therefore, the amount of developer present in the range of the third inlet portion 17 disposed behind the second inlet portion 13 becomes relatively small. Therefore, the developer is prevented from flowing back through the third inlet portion 17. Therefore, compared to the conventional configuration, the occurrence of problems such as re-adhesion of the developer to the developing roll R0k is prevented.

[0061] In addition, in the first embodiment, the supply port 3c is disposed at a position corresponding to the third inlet portion 17. The developer returning from the return chamber 6 to the mixing chamber 4 is the developer that has been used once in development. Therefore, although it is charged, the developer concentration has decreased. On the other hand, the new developer supplied from the supply port 3c may have a high developer concentration but may be insufficiently stirred and insufficiently charged. Therefore, in the first embodiment, the low-concentration developer flowing in from the third inlet portion 17 and the new developer flowing in from the supply port 3c tend to merge at the upstream end of the mixing chamber 4. Then, while being conveyed to the first inlet portion 12 at the downstream end of the mixing chamber 4, the low-concentration developer and the new developer are mixed by being stirred by the stirring auger 31, and the concentration of the developer is easily restored and the charge is easily sufficient. In the conventional configuration shown in FIG. 6A, the concentration of the low-concentration developer that short-circuits is difficult to recover, and it is easy to mix it with the new developer. When the concentration of the developer is not restored or the charge is insufficient, development defects tend to occur. Therefore, in the first embodiment, the developers are mixed more thoroughly than in the conventional configuration, and the occurrence of development defects is suppressed.

[0062] 3, the developing roll R0k of the first embodiment has a fixed magnet roll 51 as an example of a magnet means, and a rotating developing sleeve 52 as an example of a rotating means. The developer is attracted and held on the surface of the developing sleeve 52 by the magnetic force of the magnet roll 51, and the developer is transported to the developing area Q2k by the rotation of the developing sleeve 52. The magnet roll 51 is provided with a developing pole S1 at a position corresponding to the developing area Q2k facing the photosensitive drum Pk. A transport pole N1 is provided upstream of the developing pole S1 with respect to the rotation direction of the developing sleeve 52. A trimming pole S2, which is an example of a layer thickness regulating pole, is provided upstream of the transport pole N1 with respect to the rotation direction of the developing sleeve 52. A pickup pole N2, which is an example of an attracting pole, is provided upstream of the trimming pole S2 at a position facing the supply auger 21 with respect to the rotation direction of the developing sleeve 52. A pick-off pole N3, which is an example of a detaching pole, is provided upstream of the pickup pole N2 and downstream of the developing pole S1 with respect to the rotation direction of the developing sleeve 52.

[0063] The developer in the supply chamber 3 is held on the developing sleeve 52 by the magnetic force of the pickup magnetic pole N2. A trimmer 55, which is an example of a layer thickness regulating member, is disposed at a position facing the trimming magnetic pole S2. The trimmer 55 regulates the layer thickness of the developer adhering to the developing sleeve 52. Therefore, a predetermined layer thickness of developer is held on the surface of the developing sleeve 52 after the developing sleeve 52 has passed the position of the trimmer 55. The developer is held on 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 region Q2k by the rotation of the developing sleeve 52. After passing through the development region Q2k, the developer is held on the development sleeve 52 between the development pole S1 and the pick-off pole N3 and sent toward the return chamber 6. When the developer reaches between the pick-off pole N3 and the pickup pole N2, the developer is detached from the development sleeve 52 by the magnetic field between the pick-off pole N3 and the pickup pole N2, which have the same polarity, and flows into the return chamber 6.

[0064] FIG. 7 is an enlarged view of the opposing means of the first embodiment. 3 and 7, a charging film 53, which is an example of an opposing member, is supported in the developing container 1, which is an example of a developer containing means. The charging film 53 is disposed facing the developing sleeve 52, downstream of the developing zone Q2k with respect to the rotation direction of the developing sleeve 52. The charging film 53 is supported by a film supporting portion 54, which is an example of a supporting means, provided downstream of the developing zone Q2k with respect to the rotation direction of the developing sleeve 52. The film supporting portion 54 is supported by the developing container 1.

[0065] The charging film 53 and the developing sleeve 52 are disposed with a gap therebetween that is large enough to allow the developer held on the developing sleeve 52 to rub against the charging film 53 . The charging film 53 is made of a material having a charging ability with the same polarity as the developer. Therefore, when the charging polarity of the developer is negative, a material having a charging ability with a negative polarity can be used for the charging film 53. Examples of materials having a negative charging ability that can be used include fluororesins such as PTFE (polytetrafluoroethylene), PI (polyimide), PP (polypropylene), PVC (polyvinyl chloride), and POM (polyoxymethylene (polyacetal)).

[0066] When the charging film 53 rubs against the developer, the charging film 53 is triboelectrically charged. When the charging film 53 is triboelectrically charged, an electric field is generated due to the relationship between the charging potential of the charging film 53 and the developing bias of the developing roll R0k. As an example, when the charging film 53 is made of PTFE, the inventor's experiment confirmed that the charging potential is -1000 [V] or more, and when the developing bias is -600 [V], the developing sleeve 52 side is + (plus) and the charging film 53 side is - (minus). Therefore, the negatively charged developer is subjected to a force that electrostatically attracts it to the developing sleeve 52 side. Therefore, the developer that is released or floated during development in the development area Q2k is easily attracted to the developing sleeve 52 side. Therefore, compared to the case where the charging film 53 is not provided, the release of the developer is suppressed. Therefore, the floating developer is prevented from adhering to the photoconductor drum Pk and deteriorating the image quality, and the released developer is prevented from soiling the inside of the copier U. In particular, compared to the case where a voltage application device that attracts the free developer is provided, the voltage application device, i.e., the power supply and wiring, is not required. Therefore, an increase in the number of parts is suppressed. Therefore, it is possible to reduce costs. In addition, there is no need for space to install the voltage application device. Therefore, it is possible to reduce the size of the developing device Gk.

[0067] In the first embodiment, the charging film 53 rubs against the developer before it is separated from the developing sleeve 52. Therefore, the charging film 53 is disposed at a position upstream of the pick-off magnetic pole N3 in the rotation direction of the developing sleeve 52. Also, 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 rubbing. The developer is in a state along the magnetic field lines of the magnetic field. Therefore, the closer to the magnetic poles S1 and N3, the more likely the developer is to be in a standing state, so to speak, and the developer bristles are more likely to be in a fallen state at the intermediate position between the magnetic poles S1 and N3. Therefore, the developer is less likely to rub against the charged film 53 in the range where the developer bristles fall, and the developer is more likely to rub against the charged film 53 in the range where the bristles stand. The charged film 53 of the first embodiment is arranged in accordance with the rubbing range obtained in advance by experiments, etc., and is set to a length corresponding to the rubbing range. As an example, the charged film 53 of the first embodiment is arranged at a downstream position close to the pick-off magnetic pole N3 even in the film support portion 54. Therefore, compared to the case where the charged film 53 is arranged in the non-rubbing range, the charged film 53 is prevented from becoming unnecessarily long. Therefore, the manufacturing cost of the charged film 53 can be reduced.

[0068] FIG. 8A is an explanatory diagram of a conventional configuration in which an opposing member is not provided and the length of the support part is approximately the same as the sliding range, FIG. 8B is an explanatory diagram of a conventional configuration in which an opposing member is not provided and the length of the support part is longer than the sliding range, FIG. 8C is an explanatory diagram of an example of the present invention in which an opposing member is provided and the length of the support part is approximately the same as the sliding range, and FIG. 8D is an explanatory diagram of another form of the present invention in which an opposing member is provided and the length of the support part is longer than the sliding range. In FIG. 8A, in a configuration without a charging film, when the bristles 061a of the developer 061 come into contact with the support portion 054, the developer 061 is likely to come off due to the physical force generated during rubbing. Therefore, free developer is likely to be generated. As shown in FIG. 8B, when the position of the bristles 061a is on the downstream side of the support portion 054, a non-rubbing region 062 exists on the upstream side. Therefore, a portion of the free developer remains in the non-rubbing region 062. Therefore, the amount of free developer that flows out to the outside of the developing device is likely to be reduced.

[0069] In FIG. 8C , in a configuration having a charged film 53, if the length of the film support portion 54 is formed so that the range of the bristles 61a covers almost the entire area of ​​the film support portion 54, free developer can be easily collected by the electric field between the charged film 53 and the developing sleeve 52. 8D, if the length of the charged film 53' is increased to a range where the bristles 61a do not come into contact, a non-rubbing area 62 is generated. The non-rubbing area 62 is charged, although at a lower voltage than the rubbing area 63. Since the charge polarity of the non-rubbing area 62 is the same as that of the developer, some of the developer on the bristles 61a may be released by electrostatic repulsion. Therefore, it is desirable that the length of the charging film 53 corresponds to the width of the rubbing region 63 so that the non-rubbing region 62 is reduced.

[0070] The range in which the developer rubs against the charging film 53 varies depending on the positions of the magnetic poles S1 and N3 and the gap between the charging 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 floats in the developing area Q2k tends to increase. In addition, the developer held by the developing sleeve 52 tends to become bristled. Therefore, as the circumferential speed of the developing sleeve 52 increases, it is preferable to widen the rubbing range in order to improve the recovery performance in response to the increase in the amount of free developer, and it is also preferable to widen the rubbing range because the developer tends to become bristled and the rubbing range tends to become wide. Therefore, it is preferable to increase the length of the charging film 53 as the circumferential speed of the developing sleeve 52 increases. In addition, if the motor rotation speed and angular velocity are the same, the larger the diameter of the developing sleeve 52, the faster the circumferential speed becomes. Therefore, as described above, it is preferable to make the length of the charging film 53 longer as the diameter becomes larger.

[0071] Furthermore, the farther the position where the charged film 53 is disposed is from the magnetic poles S1 and N3, the more likely the brush brushes will collapse, as described above. Therefore, the farther the position is from the magnetic poles S1 and N3, the more difficult it is for the developer to rub against it, so it is preferable to shorten the charged film 53 the farther the position is from the magnetic poles S1 and N3. In other words, it is preferable to make the charged film 53 longer the closer it is to the magnetic poles S1 and N3. On the other hand, if the charged film 53 can only be disposed at a position farther from the magnetic poles S1 and N3, it is preferable to increase the length of the charged film 53 while narrowing the gap with the developing sleeve 52 to facilitate rubbing, thereby improving the recovery performance of the free developer. Also, the weaker the magnetic force of the magnetic poles S1 and N3, the more easily the brush brushes fall down. Therefore, similar to the case where the brush brush is far from the magnetic poles S1 and N3, the weaker the magnetic force of the magnetic poles S1 and N3, the more preferably the charged film 53 is shortened. In other words, the stronger the magnetic poles S1 and N3, the more preferably the charged film 53 is lengthened. Also, when the magnetic force of the magnetic poles S1 and N3 cannot be made strong, it is preferable to increase the length of the charged film 53 while narrowing the gap with the developing sleeve 52 to facilitate rubbing, thereby improving the performance of recovering free developer.

[0072] (Modification 1 of the first embodiment) FIG. 9 is an explanatory diagram of a first modified example of the first embodiment, in which an opposing member is disposed on the upstream side of the development area. 9, in the developing device Gk of the first modified example of the first embodiment, a charging film 153 is disposed between the developing zone Q2k and the trimmer 55 on the upstream side of the developing zone Q2k. The developer floating during development in the development zone Q2k may also float upstream of the development zone Q2k. Therefore, in the first modification of the first embodiment, degradation of image quality and stains due to free developer on the upstream side of the development zone Q2k are suppressed.

[0073] (Modification 2 of Example 1) FIG. 10 is an explanatory diagram of a second modified example of the first embodiment. 10, unlike the developing device Gk of the first embodiment having only one developing roll R0k, the developing device Gk of the second modification of the first embodiment has a first developing roll 201 as an example of a first developer holding means and a second developing roll 202 as an example of a second developer holding means. Along the rotation direction of the photoconductor drum Pk, the first developing roll 201 is disposed on the upstream side, and the second developing roll 202 is disposed on the downstream side.

[0074] The first developing roll 201 is supplied with developer from a supply chamber 3. The first developing roll 201 supplies the developer to the photoconductor drum Pk in a first developing area Q2a facing the photoconductor drum Pk. After passing through the first developing area Q2a, the first developing roll 201 transfers the developer to the second developing roll 202 in a transfer area 203 facing the second developing roll 202. The second developing roll 202 supplies the developer to the photoconductor drum Pk in a second developing area Q2b facing the photoconductor drum Pk. After passing through the second developing area Q2b, the second developing roll 202 returns the developer to the return chamber 6.

[0075] In the developing device Gk of the second modification of the first embodiment, similarly to the first modification of the first embodiment, a first charging film 153 as an example of a first opposing means is disposed upstream of the first developing region Q2a with respect to the rotation direction of the first developing roll 201. Also, similarly to the first embodiment, a second charging film 53 as an example of a second opposing means is disposed downstream of the second developing region Q2b with respect to the rotation direction of the second developing roll 202.

[0076] Furthermore, a third charging film 204 as an example of a third opposing means is disposed at a position on the photoconductor drum Pk side with respect to the transfer area 203. In the second modified example of the first embodiment, the third charging film 204 is disposed so as to face the first developing roll 201. Note that the third charging film 204 is not limited to the first developing roll 201, and it is also possible to dispose it so as to face the second developing roll 202, or to install two of them corresponding to the two developing rolls 201, 202.

[0077] The length of each of the charging films 53, 153, and 204 is set to a length corresponding to the range of the developer that slides over. Therefore, when the first developing roll 201 and the second developing roll 202 have different diameters and therefore different peripheral speeds, the lengths of the charging films 53, 153, and 204 can be different from each other.

[0078] Therefore, in the second modification of the first embodiment, the floating developer upstream of the first developing area Q2a can be collected by the first charging film 153. Also, the floating developer downstream of the second developing area Q2b can be collected by the second charging film 53. Therefore, the free developer can be eliminated at both ends of the opening of the developing device Gk relative to the photoconductor drum Pk. Therefore, the adverse effects of the free developer can be eliminated. Furthermore, in the second modification of the first embodiment, a third charged film 204 is also disposed at a position corresponding to the transfer area 203. Therefore, the third charged film 204 can collect free developer generated during transfer in the transfer area 203. This makes it possible to further suppress adverse effects of free developer. Although it is desirable to provide the third charged film 204, it is also possible to adopt a configuration in which no free developer is provided.

[0079] (Example of change) Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Modifications (H01) to (H05) of the present invention are illustrated below. (H01) In the above embodiment, a copier U is shown as an example of an image forming apparatus, but the present invention is not limited to this and can be applied to a facsimile or a multifunction machine having multiple functions such as a facsimile, printer, and copier. In addition, the present invention is not limited to an image forming apparatus that develops multiple colors, but can be configured as a single-color, so-called monochrome image forming apparatus. Furthermore, the present invention is not limited to an image forming apparatus, but can be applied to any electronic device or mechanical device that uses a motor and gears.

[0080] (H02) In the above embodiment, the intermediate transfer belt B is exemplified as an example of the image holding means, but the present invention is not limited to this and can be applied to a photoconductor, etc. Therefore, the image holding means is not limited to a belt-shaped member and can be applied to a drum-shaped member. (H03) In the above embodiment, the opposing means is exemplified as a film-like shape, but is not limited to this. For example, it can be in any shape, such as a lump (block shape). However, in order to reduce the size of the developing device Gk, it is preferable that the opposing means be in the form of a film (thin film).

[0081] (H04) In the first and second modified examples, it is desirable to provide the downstream charging film 53, but it is also possible to configure it without providing it. (H05) In the above embodiment, it is preferable to provide the second partition wall 16, but it is also possible to adopt the conventional configuration shown in FIG. 6A.

[0082] (Additional Note) (((1))) a developer holding means that holds a magnetic developer on its surface by magnetic force and rotates; an opposing means disposed opposite to the developer holding means, the opposing means being disposed at a position where the developer moving with the rotation of the developer holding means is rubbed against the opposing means, the opposing means being made of a material having a charging ability of the same polarity as the developer; A developing device comprising: (((2))) a developing area in which an image holding means for holding an image on its surface faces the developer holding means, the developing means being disposed downstream of the image holding means; The developing device described in (((1))) is characterized by comprising: (((3))) a developer holding means for holding an image on a surface of the developer holding means, the developer holding means being disposed upstream of the developer holding means; The developing device according to (((1))) or (((2))) comprising: (((4))) The length of the opposing means along the rotation direction of the image holding means holding the image on its surface corresponds to the width of the developer being rubbed. The developing device according to any one of ((1)) to ((3)) above. (((5))) a developer accommodating means for accommodating a developer therein, the developer accommodating means rotatably supporting the developer holding means and supporting the opposing means; Equipped with The length of the portion supporting the opposing means corresponds to the length of the opposing means. The developing device according to (((4))) above. (((6))) the opposing means being formed longer as the peripheral speed of the developer holding means increases; The developing device described in (((4))) is characterized by comprising: (((7))) the opposing means being formed longer as the diameter of the developer holding means becomes longer; The developing device described in (((4))) is characterized by comprising: (((8))) the closer the position of the facing means is to the position of the magnetic pole provided on the developer holding means, the longer the facing means is formed; The developing device described in (((4))) is characterized by comprising: (((9))) the opposing means being formed longer as the magnetic force of the magnetic pole provided in the developer holding means becomes stronger; The developing device described in (((4))) is characterized by comprising: (((10))) a developer holding means having a first developer holding means disposed opposite an image holding means that holds an image on its surface, and a second developer holding means disposed opposite the image holding means downstream of the first developer holding means along the rotation direction of the image holding means and disposed opposite the image holding means; the opposing means including a first opposing means arranged upstream of a position where the first developer holding means and the image holding means face each other with respect to a rotation direction of the first developer holding means, and a second opposing means arranged downstream of a position where the second developer holding means and the image holding means face each other with respect to a rotation direction of the second developer holding means; The developing device according to any one of ((1)) to (((9))), comprising: (((11))) the opposing means having a third opposing means disposed at a position on the image holding means side with respect to an opposing position between the first developer holding means and the second developer holding means; The developing device described in (((10))) is provided with: (((12))) the first opposing means and the second opposing means having lengths corresponding to the peripheral speeds of the first developer holding means and the second developer holding means, respectively; The developing device described in (((10))) is provided with: (((13))) An image holding means; a developing device according to any one of ((1)) to ((12)) for developing an image on the image holding means; a transfer means for transferring the image developed by the developing device from the image holding means to a medium; a fixing device for fixing the image transferred to the medium; An image forming apparatus comprising:

[0083] According to the developing device of (((1))), it is possible to suppress the release of developer while suppressing an increase in the number of parts, compared to a case where a voltage application device that attracts the released developer is provided. According to the developing device of (((2))), adhesion of free developer to the image holding means after development is suppressed, and deterioration of image quality is suppressed. According to the developing device of (((3))), adhesion of free developer to the image holding means before development is suppressed, and deterioration of image quality is suppressed. According to the developing device of (((4))), the developer can be prevented from becoming detached due to the electric field in the non-rubbing area, compared to when the length of the opposing means is longer than the width across which the developer is rubbed. According to the developing device of (((5))), it is possible to suppress the release of developer while suppressing an increase in size of the developing container, compared to a case in which the length of the portion supporting the opposing means is longer than the opposing means. According to the developing device of (((6))), the recovery capability of free developer can be improved as the circumferential speed of the developer holding means increases, compared to a case in which the opposing means is not lengthened. According to the developing device of (((7))), the longer the diameter of the developer holding means, the more improved the recovery capability of the free developer can be compared to a case in which the opposing means is not made longer. According to the developing device of (((8))), the closer the position of the opposing means is to the position of the magnetic pole of the developer holding means, the more improved the recovery capability of the free developer can be compared to a case in which the opposing means is not long. According to the developing device of (((9))), the stronger the magnetic force of the magnetic pole of the developer holding means, the more improved the recovery capability of the free developer can be compared to a case in which the opposing means is not long. According to the developing device of (((10))), free developer can be collected on the upstream side of the first developer holding means and on the downstream side of the second developer holding means. Therefore, free developer can be suppressed at the most upstream position and the most downstream position facing the image holding means. According to the developing device of (((11))), the release of developer can be suppressed compared to a case where the third opposing means is not arranged in the opposing area between the first developer holding means and the second developer holding means. According to the developing device of (((12))), even if there is a difference in peripheral speed between the first developer holding means and the second developer holding means, the opposing means according to the peripheral speed can suppress the release of developer. According to the image forming apparatus of (((13))), it is possible to suppress the release of developer while suppressing an increase in the number of parts, compared to a case where a voltage application device that attracts the released developer is provided. [Explanation of symbols]

[0084] 1...developer containing means, 53...second opposing means, 53,153,204…countermeasures, 54...part supporting the opposing means, 61, 61a...developer, 153...first opposing means, 201...first developer holding means, 202...second developer holding means, 203: a position where the first developer holding means and the second developer holding means face each other; 204...third opposing means, F: Fixing device, Gy, Gm, Gc, Gk...Developing device, N1,N2,N3,S1,S2...Magnetic pole, Py, Pm, Pc, Pk...image holding means, Q2a: Position where the first developer holding means and the image holding means face each other; Q2b: a position where the second developer holding means and the image holding means face each other; Q2k,Q2a,Q2b...development area, R0y, R0m, R0c, R0k...developer holding means, S...medium, T1y~T1k+T2+B...transcription means, U...Image forming device.

Claims

1. a developer holding means that holds a magnetic developer on its surface by magnetic force and rotates; an opposing means disposed opposite to the developer holding means, the opposing means being disposed at a position where the developer moving with the rotation of the developer holding means is rubbed against the opposing means, the opposing means being made of a material having a charging ability of the same polarity as the developer; A developing device comprising:

2. a developing area in which an image holding means for holding an image on its surface faces the developer holding means, the developing means being disposed downstream of the image holding means; The developing device according to claim 1 , further comprising:

3. a developer holding means for holding an image on a surface of the developer holding means, the developer holding means being disposed upstream of the developer holding means; The developing device according to claim 1 , further comprising:

4. The length of the opposing means along the rotation direction of the image holding means holding the image on its surface corresponds to the width of the developer being rubbed.

2. The developing device according to claim 1,

5. a developer accommodating means for accommodating a developer therein, the developer accommodating means rotatably supporting the developer holding means and supporting the opposing means; Equipped with The length of the portion supporting the opposing means corresponds to the length of the opposing means.

5. The developing device according to claim 4.

6. the opposing means being formed longer as the peripheral speed of the developer holding means increases; The developing device according to claim 4, further comprising:

7. the opposing means being formed longer as the diameter of the developer holding means becomes longer; The developing device according to claim 4, further comprising:

8. the closer the position of the facing means is to the position of the magnetic pole provided on the developer holding means, the longer the facing means is formed; The developing device according to claim 4, further comprising:

9. the opposing means being formed longer as the magnetic force of the magnetic pole provided in the developer holding means becomes stronger; The developing device according to claim 4, further comprising:

10. a developer holding means having a first developer holding means disposed opposite an image holding means that holds an image on its surface, and a second developer holding means disposed opposite the image holding means downstream of the first developer holding means along a rotation direction of the image holding means and disposed opposite the image holding means; the opposing means including a first opposing means arranged upstream of a position where the first developer holding means and the image holding means face each other with respect to a rotation direction of the first developer holding means, and a second opposing means arranged downstream of a position where the second developer holding means and the image holding means face each other with respect to a rotation direction of the second developer holding means; The developing device according to claim 1 , further comprising:

11. the opposing means having a third opposing means disposed at a position on the image holding means side with respect to an opposing position between the first developer holding means and the second developer holding means; The developing device according to claim 10, further comprising:

12. the first opposing means and the second opposing means having lengths corresponding to the peripheral speeds of the first developer holding means and the second developer holding means, respectively; The developing device according to claim 10, further comprising:

13. An image holding means; a developing device according to any one of claims 1 to 12, which develops the image on said image holding means; a transfer means for transferring the image developed by the developing device from the image holding means to a medium; a fixing device for fixing the image transferred to the medium; An image forming apparatus comprising:

Images