Developing device and image forming device

Abstract

To more efficiently recover a developer accumulated in the inside of a regulating member and a shielding member of a developing device, compared with a configuration in which a developer leaking from a shielding member is collected by sucking air from the downstream side of the shielding member.SOLUTION: There is provided a developing device that has a developing roll 332 which supplies a developer to an image holder on which a latent electrostatic image is formed, a regulating member 337 which regulates the amount of the developer held by the developing roll 332, a cover 339 as a shielding member covering part of the developing roll 332 and the regulating member 337, a flow path 51 which allows air to flow in from a first inlet provided on the downstream side of the operation of the developing roll 332 in the covered area covered with the cover 339 of the developing roll 332, and a flow path 52 which allows air to flow in from a second inlet provided on the upstream side of the operation of the developing roll 332, and that comprises a suction part which suctions air through the flow path 51 and flow path 52.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] In an electrophotographic image forming apparatus, in order to prevent developer from leaking from a developing device, a shielding member that covers part of the developer holder to prevent the developer from scattering, and a flow path that sucks up and collects the developer are provided.

[0003] Patent document 1 discloses that a duct is provided that communicates with the opposing area between the toner carrier and the toner supplier via a through hole, and an exhaust device creates negative pressure inside the duct, thereby forming an airflow that flows from the space near the opposing area through the duct toward the exhaust device.

[0004] Patent Document 2 discloses that a cover is provided to cover a portion of a developer carrier, an outlet for air to flow out is formed between the developer carrier and the tip of the cover, and an air inlet is formed in the cover, forming a unidirectional air flow from the inlet to the outlet along the developer carrier. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6010058 [Patent Document 2] Patent No. 4752663 Summary of the Invention [Problem to be solved by the invention]

[0006] If the amount of developer scattered inside the developing device increases, the developer leaking from the shielding member cannot be collected, which causes a decrease in the quality of the formed image.

[0007] The present invention aims to more efficiently recover developer that has accumulated inside the regulating member and shielding member of the developing device, compared to a configuration in which air is sucked in from the downstream side of the shielding member to recover developer that has leaked from the shielding member. [Means for solving the problem]

[0008] The present invention according to claim 1 is a developer carrier for supplying a developer to an image carrier on which an electrostatic latent image is formed; a regulating member for regulating an amount of developer held on the developer holder; a shielding member for covering a part of the developer carrier and the regulating member; a suction section that has a first flow path through which air flows in from a first inlet provided on the downstream side of the operation of the developer carrier in a covered area of ​​the developer carrier that is covered by the shielding member, and a second flow path through which air flows in from a second inlet provided on the upstream side of the operation of the developer carrier, and that sucks in air via the first flow path and the second flow path; The developing device is characterized by comprising: The present invention according to claim 2 is 2. The developing device according to claim 1, wherein the first flow path and the second flow path of the suction section merge midway to form one flow path. The present invention according to claim 3 is 3. The developing device according to claim 2, wherein the second flow path is narrower than the first flow path. The present invention according to claim 4 is the developer carrier includes a rotating developing sleeve and a magnet roll having a plurality of magnetic poles and provided inside the developing sleeve; the second inlet of the suction portion is provided at a position facing a portion between the two magnetic poles of the developer carrier; The developing device according to claim 1 is characterized in that: The present invention according to claim 5 is 5. The developing device according to claim 4, wherein the second inlet is provided at a position facing a substantially central portion between the two magnetic poles in the developer carrier. The present invention according to claim 6 is 2. The developing device according to claim 1, wherein the second flow path of the suction unit has a higher negative pressure than the first flow path. The present invention according to claim 7 is 2. The developing device according to claim 1, wherein the second flow path of the suction portion is formed as a gap between the regulating member and the shielding member. The present invention according to claim 8 is An image forming apparatus comprising the developing device according to any one of claims 1 to 7. Effect of the Invention

[0009] According to the invention of claim 1, developer that has leaked from the shielding member can be more efficiently recovered than developer that has accumulated inside the regulating member and shielding member of the developing device, compared to a configuration in which air is sucked in from the downstream side of the shielding member to recover developer that has leaked from the shielding member. According to the invention of claim 2, the configuration can be simplified and costs can be reduced, as compared with a configuration in which a suction mechanism is provided for each flow path. According to the invention of claim 3, the negative pressure in the second flow path is higher than that in the first flow path, so that the developer remaining inside the shielding member can be sucked in without scattering. According to the invention of claim 4, compared to a configuration in which an inlet is provided at a position corresponding to a magnetic pole, the scattered developer can be sucked in more efficiently. According to the invention of claim 5, by providing the inflow port at a position on the developer carrier where the developer is likely to scatter, the developer can be sucked in more efficiently. According to the sixth aspect of the present invention, the developer remaining inside the shielding member can be sucked in without scattering. According to the invention of claim 7, the number of parts can be reduced, the configuration can be simplified, and costs can be reduced, compared to a configuration in which a separate duct is provided. According to the invention of claim 8, in a developing device provided in an image forming apparatus, developer that has leaked from a shielding member can be more efficiently recovered than a configuration in which air is sucked in from the downstream side of the shielding member to recover developer that has leaked from the shielding member. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an image forming apparatus to which the present embodiment is applied. [Diagram 2] FIG. 2 is a perspective view showing an internal configuration of a developing unit. [Diagram 3] FIG. 2 is a cross-sectional view showing an internal configuration of the developing unit. [Figure 4] 4 is an enlarged view of a main part of the developing unit shown in FIG. 3. [Diagram 5] 4 is a diagram showing a discharge path of the developer continuing from the space shown in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <Configuration of Image Forming Apparatus> 1 is a diagram illustrating an image forming apparatus 1 to which this embodiment is applied. The image forming apparatus 1 according to this embodiment includes a paper feed unit 1A, a printing unit 1B, and a paper discharge unit 1C. The paper feed unit 1A includes a first paper storage section 11 to a fourth paper storage section 14 that store paper P as an example of a recording medium. The paper feed unit 1A also includes feed rolls 15 to 18 that are provided corresponding to the first paper storage section 11 to the fourth paper storage section 14, respectively, and that feed paper P stored in each paper storage section to a transport path connected to the printing unit 1B.

[0012] The printing unit 1B includes an image forming section 20 that forms an image on paper P. The printing unit 1B also includes a control section 21 that controls each section of the image forming device 1. The printing unit 1B also includes an image processing section 22. The image processing section 22 performs image processing on image data transmitted from the image reading device 4 and a personal computer (PC) 5. The printing unit 1B also includes a UI (User Interface) 23 that is composed of a touch panel or the like and that notifies the user of information and accepts information input from the user.

[0013] Image forming section 20, which is an example of an image forming means, is provided with six image forming units 30T, 30P, 30Y, 30M, 30C, and 30K (hereinafter, sometimes simply referred to as "image forming units 30") that are arranged in parallel at regular intervals. Each image forming unit 30 is provided with a photoconductor drum 31 on which an electrostatic latent image is formed while rotating in the direction of arrow A, a charging roll 32 that charges the surface of photoconductor drum 31, a developing device 33 that develops the electrostatic latent image formed on photoconductor drum 31, and a drum cleaner 34 that removes toner and the like from the surface of photoconductor drum 31.

[0014] The image forming section 20 is also provided with an exposure device 26 that exposes the photoconductor drum 31 of each image forming unit 30 with laser light. The exposure of the photoconductor drum 31 by the exposure device 26 is not limited to using laser light. For example, a light source such as an LED (Light Emitting Diode) may be provided for each image forming unit 30, and the photoconductor drum 31 may be exposed using light emitted from the light source.

[0015] Each image forming unit 30 is configured similarly, except for the toner contained in the developer 33. The image forming units 30Y, 30M, 30C, and 30K form toner images in yellow (Y), magenta (M), cyan (C), and black (K), respectively. The image forming units 30T and 30P form toner images using toner corresponding to the corporate color, foaming toner for Braille, fluorescent toner, toner for improving gloss, and the like. In other words, the image forming units 30T and 30P form toner images using toner of a special color.

[0016] The image forming section 20 is also provided with an intermediate transfer belt 41 onto which the toner images of each color formed on the photoconductor drums 31 of the image forming units 30 are transferred. The image forming section 20 is also provided with a primary transfer roll 42 that transfers the toner images of each color of the image forming units 30 onto the intermediate transfer belt 41 at a primary transfer section T1. The image forming section 20 is also provided with a secondary transfer roll 40 that collectively transfers the toner images transferred onto the intermediate transfer belt 41 onto the paper P at a secondary transfer section T2. ​​The image forming section 20 is also provided with a belt cleaner 45 that removes toner, etc. from the surface of the intermediate transfer belt 41, and a fixing device 80 that fixes the secondarily transferred image onto the paper P.

[0017] The image forming section 20 performs an image forming operation based on a control signal from the control section 21. Specifically, in the image forming section 20, first, image processing is performed by the image processing section 22 on the image data input from the image reading device 4 or the PC 5, and the image data after the image processing is supplied to the exposure device 26. Then, for example, in the magenta (M) image forming unit 30M, after the surface of the photosensitive drum 31 is charged by the charging roll 32, the exposure device 26 irradiates the photosensitive drum 31 with laser light modulated by the image data obtained from the image processing section 22.

[0018] As a result, an electrostatic latent image is formed on the photoconductor drum 31. The formed electrostatic latent image is developed by the developer 33, and a magenta toner image is formed on the photoconductor drum 31. Similarly, yellow, cyan and black toner images are formed in the image forming units 30Y, 30C and 30K, and special color toner images are formed in the image forming units 30T and 30P.

[0019] The color toner images formed in the image forming units 30 are sequentially electrostatically transferred onto an intermediate transfer belt 41 rotating in the direction of arrow C in Fig. 1 by a primary transfer roll 42, and superimposed toner images are formed on the intermediate transfer belt 41. The superimposed toner images formed on the intermediate transfer belt 41 are transported to a secondary transfer section T2 constituted by a secondary transfer roll 40 and a backup roll 49 as the intermediate transfer belt 41 moves.

[0020] On the other hand, the paper P is taken out of the first paper storage unit 11 by, for example, the delivery roll 15, and then transported to the position of the registration roll 74 via the transport path. When the superimposed toner image is transported to the secondary transfer unit T2, the paper P is supplied from the registration roll 74 to the secondary transfer unit T2 in accordance with the timing. Then, at the secondary transfer unit T2, the superimposed toner image is electrostatically transferred onto the paper P all at once due to the action of the transfer electric field formed between the secondary transfer roll 40 and the backup roll 49.

[0021] Thereafter, the paper P onto which the superimposed toner image has been electrostatically transferred is transported to the fixing device 80. In the fixing device 80, pressure and heat are applied to the paper P on which the unfixed toner image has been formed, and the toner image is fixed to the paper P. Then, the paper P which has undergone the fixing process passes through a curl correction section 81 provided in the paper discharge unit 1C, and is then transported to a paper stacking section (not shown).

[0022] <Configuration of Developer 33> Figures 2 and 3 are diagrams showing the internal structure of developing unit 33. Figure 2 is a perspective view of developing unit 33 seen from the front side (the front side of the paper in Figure 1) of printing unit 1B of image forming apparatus 1 shown in Figure 1 toward the rear side (the rear side of the paper in Figure 1), and is a cross-sectional view with the front side broken away. Figure 3 is a diagram of developing unit 33 seen from the front side toward the rear side, and is a cross-sectional view with the front side broken away.

[0023] The developing device 33 has a housing 331 adjacent to the photosensitive drum 31 and configured as a housing extending from the front side to the rear side of the printing unit 1B. The housing 331 has an opening 331a at a position facing the photosensitive drum 31. Inside the housing 331, a developing roll 332, a pickup roll 333, a first conveying section 334, a second conveying section 335, a third conveying section 336, a regulating member 337, and a removing member 338 are housed together with the developer. A cover 339 for suppressing scattering of the developer is provided below the opening 331a of the housing 331. Each of the members inside the housing 331 is a long member having approximately the same length and is arranged approximately in parallel. The developer housed in the housing 331 is composed of a mixture of toner for forming an image and carrier, which is a magnetic particle for transporting the toner. In addition, each member including the housing 331 is covered by an outer shell 60. The developing device 33 is an example of a developing unit.

[0024] The developing roll 332 includes a cylindrical shaft member and a cylindrical sleeve that covers the shaft member. The developing roll 332 is disposed so that a part of the side surface is exposed from the opening 331a of the storage section 331, and the exposed surface faces the photosensitive drum 31. The shaft member of the developing roll 332 has a magnetic force, and the sleeve rotates around the shaft member in the direction of the arrow shown in the figure. The developing roll 332 attracts a developer onto the surface of the sleeve by the magnetic force of the shaft member, transports the developer to the opening 331a by rotating the sleeve, and develops an electrostatic latent image by attaching the toner to the charged photosensitive drum 31. The developing roll 332 is an example of a developer holder.

[0025] The pickup roll 333 is provided adjacent to and parallel to the developing roll 332. The pickup roll 333 includes a cylindrical shaft member and a cylindrical sleeve that covers the shaft member. The shaft member has a magnetic force, and the sleeve rotates around the shaft member. The pickup roll 333 attracts the developer onto the surface of the sleeve by the magnetic force of the shaft member, and conveys the developer by rotating the sleeve to transfer it to the developing roll 332.

[0026] The first conveying section 334, the second conveying section 335, and the third conveying section 336 are augers having spiral blades around a rotation axis. The first conveying section 334, the second conveying section 335, and the third conveying section 336 are arranged inside the storage section 331 with their rotation axes parallel to the developing roll 332 and the pick-up roll 333. By rotating the first conveying section 334, the second conveying section 335, and the third conveying section 336 around their respective rotation axes, the developer is agitated and conveyed in a direction along the rotation axis of each of the conveying sections 334 to 336. In addition, the developer is conveyed in the order of the first conveying section 334, the second conveying section 335, and the third conveying section 336 in accordance with the rotational operation of the first conveying section 334, the second conveying section 335, and the third conveying section 336, and is supplied from the third conveying section 336 to the pick-up roll 333.

[0027] The regulating member 337 is provided along the side surface of the developing roll 332, downstream of the position where the developing roll 332 faces the pickup roll 333, and upstream of the position where the developing roll 332 faces the photoconductor drum 31. Here, the downstream side and the upstream side refer to the downstream side and the upstream side in the rotation direction of the developing roll 332. The regulating member 337 scrapes off the developer supplied from the pickup roll 333 and held on the surface of the developing roll 332, and regulates it to a certain height. The developer scraped off by the regulating member 337 is collected inside the storage section 331 and returns to the transport path configured by the first transport section 334, the second transport section 335, and the third transport section 336.

[0028] More specifically, the regulating member 337 includes a regulating roll 337a and a regulating blade 337b that are disposed at a fixed interval from the surface of the developing roll 332. The regulating roll 337a is a roll member that is disposed with its axis direction parallel to the axis direction of the developing roll 332, and presses the developer supplied from the pickup roll 333 to the developing roll 332 to a fixed height from the surface of the developing roll 332. The regulating blade 337b is a blade that extends parallel to the axis direction of the developing roll 332, and scrapes off the developer at the tip of the layer so that the layer of the developer pressed by the regulating roll 337a has a fixed height. The developer scraped off by the regulating blade 337b falls downward between the regulating roll 337a and the regulating blade 337b, and is collected inside the storage unit 331.

[0029] The removing member 338 is provided along the side surface of the developing roll 332, downstream of the position where the developing roll 332 faces the photosensitive drum 31. The downstream side is the downstream side in the rotation direction of the developing roll 332. The removing member 338 scrapes off the developer remaining on the surface of the developing roll 332 after the developing roll 332 supplies the developer to the photosensitive drum 31. The developer scraped off from the developing roll 332 by the removing member 338 is collected inside the storage section 331 and returns to the transport path configured by the first transport section 334, the second transport section 335, and the third transport section 336.

[0030] The cover 339 is a member that suppresses exposure of the developing roll 332 at the opening 331a of the storage section 331. The cover 339 is composed of a covering portion 339a that covers the surface of the developing roll 332 at a certain interval, and a guide piece 339b that extends downward from one end side of the covering portion 339a. The covering portion 339a is a plate-shaped member having an arc-shaped cross section that follows the surface of the developing roll 332, and covers the surface of the developing roll 332 to suppress the developer from scattering. The guide piece 339b is provided on the upstream edge of the covering portion 339a in the rotation direction of the developing roll 332 so as to be away from the developing roll 332. The guide piece 339b is provided in parallel to the regulating blade 337b of the regulating member 337 so as to cover the regulating blade 337b at a certain interval. The cover 339 is an example of a shielding member. The developer that separates from the surface of the developing roll 332 after passing through the regulating blade 337b is discharged from the space S surrounded by the surface of the developing roll 332, the cover portion 339a, and the regulating blade 337b through the gap between the guide piece 339b and the regulating blade 337b.

[0031] A support block 61 that supports the containing portion 331 is provided inside the outer shell 60, and this support block 61 separates the containing portion 331 from the outer shell 60 to form a space 50. This space 50 continues from the front side to the rear side of the developing device 33, and serves as a discharge flow path (duct) for discharging the developer that has flowed out of the containing portion 331 from the gap between the cover 339 and the regulating blade 337b or the opening 331a.

[0032] <Discharge of developer separated from developing roll 332> Fig. 4 is an enlarged view of the main part of the developing device 33 shown in Fig. 3. Discharge of the developer scattered from the surface of the developing roll 332 will be further described with reference to Figs. 2 to 4. First, transportation of the developer by the developing roll 332 will be described.

[0033] As described above, the developing roll 332 includes a shaft member 332a having a magnetic force and a cylindrical sleeve 332b rotatable around the shaft member 332a. The shaft member 332a of the developing roll 332 is provided with a plurality of magnetic poles 332c. In the example shown in FIG. 4, five magnetic poles 332c are provided radially in a semicircular portion on the side of the opening 331a of the storage section 331 in the cross section of the shaft member 332a. These magnetic poles 332c are arranged so that the polarities of adjacent magnetic poles 332c are opposite to each other. As a result, the developer supplied from the pickup roll 333 (see FIG. 2) is attracted to the sleeve 332b by the magnetic field generated by the magnetic poles 332c, and is transported toward the opening 331a as the sleeve 332b rotates.

[0034] Here, the toner contained in the developer is charged in the process of being conveyed and stirred by the first conveying section 334, the second conveying section 335, and the third conveying section 336. The developing roll 332 faces the photoconductor drum 31, which is charged to a polarity different from that of the toner, at the opening 331a. Therefore, when the developer is conveyed by the rotation of the sleeve 332b and reaches the opening 331a, the toner contained in the developer is attracted to the photoconductor drum 31. Thereafter, the developer, which includes the carrier and the toner that is not attracted to the photoconductor drum 31, is further conveyed by the rotation of the sleeve 332b and returns to the storage section 331, and is scraped off from the sleeve 332b by the removal member 338 (see FIG. 2).

[0035] As described above, the developer is transported on the surface of the developing roll 332, and during this process, a part of the developer attached to the developing roll 332 is dispersed downstream of the regulating member 337 in the rotation direction of the developing roll 332. For example, a part of the developer scraped off by the regulating blade 337b reaches the space S beyond the regulating blade 337b. In addition, the layer of the developer scraped off by the regulating blade 337b may be dispersed by the movement of the sleeve 332b or by contact with the surface of the cover 339 facing the developing roll 332. The developer dispersed from the developing roll 332 floats in the space S or scatters out from the end of the cover 339 on the downstream side (the opening 331a side) in the rotation direction of the developing roll 332. Therefore, a configuration is provided to allow the developer dispersed from the developing roll 332 to flow in and be discharged.

[0036] Specifically, the gap between the cover 339 and the outer shell 60 of the developing device 33 serves as a flow path for sucking in and discharging the developer scattered from the opening 331a side of the cover 339 (see dashed arrow 51 in FIG. 4). This flow path is referred to as "flow path 51." The flow path 51 is an example of a first flow path. A gap is provided between the guide piece 339b of the cover 339 and the regulating blade 337b to form a flow path for discharging the developer floating in the space S (see dashed arrow 52 in FIG. 4). This flow path is referred to as "flow path 52." The flow path 52 is an example of a second flow path. The developer scattered from the developing roll 332 is guided to the space 50 (see FIG. 3) by these two flow paths 51 and 52 and discharged.

[0037] <Structure of the developer discharge passage> Next, the structure of the developer discharge flow path including the flow paths 51 and 52 will be described with reference to FIG. 3 and FIG. 4. As described above, the flow paths 51 and 52 are provided as flow paths for discharging the developer dispersed from the surface of the developing roll 332. These two flow paths 51 and 52 join midway and are connected to the space 50. The space 50 forms a flow path and is connected to an exhaust device, and the exhaust device sucks in air to form an air flow path from the flow paths 51 and 52 to the space 50 via the exhaust device. According to this air flow, the developer floating in the space S or near the opening 331a flows into the flow paths 51 and 52 and is discharged through the space 50. The flow path including the space 50 and the exhaust device will be described later.

[0038] Comparing flow path 51 and flow path 52, in the cross section shown in FIG. 4, flow path 52 is narrower than flow path 51. Therefore, when air is sucked from space 50 where flow paths 51 and 52 join, flow path 52 has a higher negative pressure than flow path 51. With this configuration, the developer floating or remaining between cover portion 339a of cover 339 and developing roll 332 is pulled back to the upstream side in the rotation direction of developing roll 332 and discharged from flow path 52. As a result, more developer is sucked into flow path 52, and scattering of developer on the opening 331a side is suppressed.

[0039] The inlets of the flow paths 51 and 52 will be further described. As shown in Fig. 4, the flow path 51 is formed by the outer surface of the cover 339 and the inner surface of the outer shell 60 of the developing device 33. The inlet of the flow path 51 is formed by the end of the cover 339 on the downstream side (the opening 331a side) in the rotation direction of the developing roll 332 and the end of the outer shell 60 on the opening 331a side. As a result, the developer that has exceeded the cover 339 and scattered near the opening 331a and is floating is sucked into the flow path 51 from the inlet of the flow path 51. The inlet of the flow path 51 is an example of a first inlet.

[0040] The flow path 52 is formed by the mutually opposing surfaces of the guide piece 339b of the cover 339 and the regulating blade 337b of the regulating member 337. The inflow port of the flow path 52 is formed at the end of the opposing surfaces of the guide piece 339b and the regulating blade 337b on the space S side. As a result, the developer separated from the developing roll 332 in the space S is sucked into the flow path 52 from the inflow port of the flow path 52. The inflow port of the flow path 52 is an example of a second inflow port.

[0041] More specifically, the inlet of the flow path 52 is provided at a position facing a portion between two adjacent magnetic poles 332c of the magnetic poles 332c provided on the shaft member 332a of the developing roll 332 among the portions on the surface of the developing roll 332. In the example shown in FIG. 4, the inlet of the flow path 52 is provided at a position facing a portion at the approximate center between two adjacent magnetic poles 332c. As mentioned above, on the surface of the developing roll 332, the developer is attracted to the sleeve 332b by the magnetic field generated by the magnetic poles 332c. Also, it was mentioned that the adjacent magnetic poles 332c are arranged so that their polarities are opposite to each other. Due to this configuration, the developer attracted to the sleeve 332b forms a layer like a row of developer ears stacked on top of each other so as to rise from the surface of the sleeve 332b at the position of the magnetic poles 332c. Then, as the developer layer is transported by the rotation of the sleeve 332b and moves away from the magnetic pole 332c, it gradually falls in the direction of rotation of the sleeve 332b. As the sleeve 332b continues to rotate and the developer layer approaches the next magnetic pole 332c, the developer layer gradually stands upright with the tip of the developer layer in contact with the surface of the sleeve 332b. In this process, the magnetic field is weakened between the two magnetic poles 332c where the developer layer falls, so that the developer is more likely to be scattered from the surface of the sleeve 332b than when the developer layer is located on one of the magnetic poles 332c. Therefore, by positioning the inlet of the flow path 52 at a position facing the portion between the two adjacent magnetic poles 332c, the developer scattered from the surface of the sleeve 332b is efficiently allowed to flow into the flow path 52.

[0042] 5 is a diagram showing a developer discharge path continuing from the space 50 shown in FIG. 3. FIG. 5 shows a part of the rear side of the developing device 33, a suction hose 54 connected to the developing device 33, and an exhaust device 55. In FIG. 5, the space 50 is not shown, but a duct portion for flowing air from the developing device 33 to the suction hose 54 is given the reference symbol 50. One end of the suction hose 54 is connected to a through hole 53 provided at the end of the duct portion of the developing device 33. The other end of the suction hose 54 is connected to an exhaust device 55. The exhaust device 55 is disposed, for example, at the rear (the back side in FIG. 1) of the printing unit 1B (see FIG. 1) of the image forming apparatus 1.

[0043] The exhaust device 55 is provided with a fan 56, and by rotating the fan 56, the air in the space 50 of the developing device 33 is sucked in through the suction hose 54. As a result, the floating developer is sucked in together with the air from the inlets of the flow paths 51 and 52, and is discharged to the exhaust device 55 through the flow paths 51 and 52, the space 50, and the suction hose 54. The exhaust device 55 is also provided with a filter (not shown) that collects the developer discharged from the developing device 33 together with the air. The space 50, the suction hose 54, and the exhaust device 55 are an example of a suction section.

[0044] Although the embodiment of the present invention has been described above, the technical scope of the present invention is not limited to the above embodiment. Various modifications and alternative configurations that do not depart from the scope of the technical idea of ​​the present invention are included in the present invention.

[0045] <Additional Notes> (((1))) a suction section that sucks air through the first flow path and the second flow path, the suction section having a first flow path through which air flows in from a first inlet provided on the downstream side of the operation of the developer holder in a covered area of ​​the developer holder that is covered by the shielding member, and a second flow path through which air flows in from a second inlet provided on the upstream side of the operation of the developer holder, the suction section being configured to suck air through the first flow path and the second flow path. (((2))) The developing device described in (((1))), wherein the first flow path and the second flow path of the suction section merge midway to form a single flow path. (((3))) The developing device according to (((1))) or (((2))), wherein the second flow path is narrower than the first flow path. (((4))) The developing device described in any one of (((1))) to (((3))), characterized in that the developer holder includes a rotating developing sleeve and a magnet roll having a plurality of magnetic poles and provided inside the developing sleeve, and the second inlet of the suction section is provided at a position facing a portion between the two magnetic poles in the developer holder. (((5))) The developing device described in (((4))), wherein the second inlet is provided at a position facing a substantially central portion between the two magnetic poles in the developer holder. (((6))) The developing device according to any one of (((1))) to (((5))), wherein the second flow path of the suction unit is set at a higher negative pressure than the first flow path. (((7))) The developing device described in any one of (((1))) to (((6))), wherein the second flow path of the suction portion is formed as a gap between the regulating member and the shielding member. (((8))) An image forming apparatus comprising the developing device according to any one of ((1))) to (((7))).

[0046] According to the developing device of (((1))), the developer that has leaked from the shielding member can be more efficiently recovered than in a configuration in which air is sucked in from the downstream side of the shielding member to recover the developer that has leaked from the shielding member. According to the developing device of (((2))), the configuration can be simplified and costs can be reduced, compared to a configuration in which a suction mechanism is provided for each flow path. According to the developing device of (((3))), the negative pressure in the second flow path is higher than that in the first flow path, so that the developer remaining inside the shielding member can be sucked in without scattering. According to the developing device of (((4))), scattering developer can be sucked in more efficiently than in a configuration in which an inlet is provided at a position corresponding to the magnetic pole. According to the developing device of (((5))), by providing an inlet at a position on the developer carrier where the developer is likely to scatter, the developer can be sucked in more efficiently. According to the developing device of (((6))), the developer remaining inside the shielding member can be sucked in without scattering. According to the developing device of (((7))), the number of parts can be reduced, the configuration can be simplified, and costs can be reduced, compared to a configuration in which a separate duct is provided. According to the image forming device of (((8))), in the developing device, developer that has leaked from the shielding member is recovered by sucking air from the downstream side of the shielding member, so that developer that has accumulated inside the regulating member and the shielding member of the developing device can be recovered more efficiently. [Explanation of symbols]

[0047] 1...image forming apparatus, 1B...printing unit, 33...developing device, 331...storage section, 331a...opening, 332...developing roll, 333...pickup roll, 334...first conveying section, 335...second conveying section, 336...third conveying section, 337...regulating member, 337a...regulating roll, 337b...regulating blade, 338...removal member, 339...cover, 339a...covering section, 339b...guiding piece, 50...space, 51...flow path, 52...flow path, 53...through hole, 54...suction hose, 55...exhaust device, 56...fan, 60...outer shell, 61...support block

Claims

1. a developer carrier for supplying a developer to an image carrier on which an electrostatic latent image is formed; a regulating member for regulating an amount of developer held on the developer holder; a shielding member for covering a part of the developer carrier and the regulating member; a suction section that has a first flow path through which air flows in from a first inlet provided on the downstream side of the operation of the developer carrier in a covered area of ​​the developer carrier that is covered by the shielding member, and a second flow path through which air flows in from a second inlet provided on the upstream side of the operation of the developer carrier, and that sucks in air via the first flow path and the second flow path; A developing device comprising:

2. 2. The developing device according to claim 1, wherein the first flow path and the second flow path of the suction portion merge midway to form one flow path.

3. The developing device according to claim 2 , wherein the second flow path is narrower than the first flow path.

4. the developer carrier includes a rotating developing sleeve and a magnet roll having a plurality of magnetic poles and provided inside the developing sleeve; the second inlet of the suction portion is provided at a position facing a portion between the two magnetic poles of the developer carrier; 2. The developing device according to claim 1,

5. 5. The developing device according to claim 4, wherein the second inlet is provided at a position facing a substantially central portion between the two magnetic poles in the developer carrier.

6. 2. The developing device according to claim 1, wherein the second flow path of the suction portion has a higher negative pressure than the first flow path.

7. The developing device according to claim 1 , wherein the second flow path of the suction portion is formed as a gap between the regulating member and the shielding member.

8. 8. An image forming apparatus comprising the developing device according to claim 1.

Images