Developing device and image forming apparatus

Abstract

A developing device includes: a developer holding body that supplies a developer to an image holding body on which an electrostatic latent image is formed; a regulating member that regulates an amount of the developer held by the developer holding body; a shielding member covering a portion of the developer holding body and the regulating member; and a suction part 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 holding body, 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 holding body, in a covered region of the developer holding body covered by the shielding member. And air is sucked through the first flow path and the second flow path.

Description

Technical Field

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

[0002] In an image forming apparatus utilizing an electrophotographic method, in order to suppress leakage of developer from a developing device, a shielding member that covers a portion of a developer holding member to suppress scattering of the developer or a flow path that sucks and recovers the developer is provided.

[0003] Patent Document 1 discloses that a duct is provided to communicate between the facing regions of a toner carrier and a toner supplier via a through hole, and an exhaust device is used to make the interior of the duct negatively pressurized, thereby forming an airflow from a space near the facing region through the duct toward the exhaust device.

[0004] Patent document 2 discloses the following: a cover is provided to cover a portion of a developer carrier, an air outlet is formed between the developer carrier and the end of the cover, an air inlet is formed on the cover, and an air flow is formed in one direction along the developer carrier from the inlet toward the outlet.

[0005] Patent Document 1: Japanese Patent No. 6010058

[0006] Patent Document 2: Japanese Patent No. 4752663 Summary of the invention

[0007] If the developer scattered inside the developing device increases, the developer leaked from the shielding member cannot be completely recovered, resulting in a decrease in the quality of the formed image.

[0008] An object of the present invention is to more efficiently recover developer retained inside a restricting member and a shielding member of a developing device, compared with a structure in which air is sucked from a downstream side of the shielding member to recover developer leaking from the shielding member.

[0009] The present invention according to claim 1 is a developing device, characterized by comprising:

[0010] A developer holding body for supplying a developer to an image holding body on which an electrostatic latent image is formed;

[0011] a limiting member for limiting the amount of the developer held by the developer holding body;

[0012] a shielding member covering a portion of the developer holding body and the limiting member; and

[0013] The suction portion has a first flow path for allowing air to flow in from a first inlet provided on the downstream side of the movement of the developer holding body, and a second flow path for allowing air to flow in from a second inlet provided on the upstream side of the movement of the developer holding body, in a covered area of ​​the developer holding body covered by the shielding member, and air is sucked through the first flow path and the second flow path.

[0014] The present invention according to claim 2 is characterized in that in the developing device according to claim 1,

[0015] The first flow path and the second flow path of the suction portion merge into one flow path in the middle.

[0016] The present invention according to claim 3 is characterized in that, in the developing device according to claim 1 or claim 2,

[0017] The second flow path is narrower than the first flow path.

[0018] The present invention according to claim 4 is characterized in that in the developing device described in any one of claims 1 to 3,

[0019] The developer holding body includes a rotating developing sleeve and a magnet roller having a plurality of magnetic poles and disposed inside the developing sleeve.

[0020] The second inlet of the suction portion is provided at a position facing a portion between the two magnetic poles of the developer holding member.

[0021] The present invention according to claim 5 is characterized in that in the developing device according to claim 4,

[0022] The second inlet is provided at a position facing a substantially central portion between the two magnetic poles of the developer holding member.

[0023] The invention according to claim 6 is characterized in that in the developing device described in any one of claims 1 to 5,

[0024] The second flow path of the suction unit is set to have a higher negative pressure than the first flow path.

[0025] The present invention according to claim 7 is characterized in that in the developing device described in any one of claims 1 to 6,

[0026] The second flow path of the suction portion is formed as a gap between the restriction member and the shielding member.

[0027] The present invention according to claim 8 is an image forming apparatus including the developing device according to any one of claims 1 to 7.

[0028] Effects of the Invention

[0029] According to the first aspect of the present invention, compared with a structure in which air is sucked from the downstream side of the shielding member to recover the developer leaking from the shielding member, the developer remaining inside the regulating member and the shielding member of the developing device can be recovered more efficiently.

[0030] According to the second aspect of the present invention, compared with a configuration in which a suction mechanism is provided for each flow path, the configuration can be simplified and the cost can be reduced.

[0031] According to the third aspect of the present invention, since the negative pressure of the second flow path is higher than that of the first flow path, the developer remaining inside the shielding member can be sucked without scattering.

[0032] According to the fourth aspect of the present invention, compared with a configuration in which the inlet port is provided at a position corresponding to the magnetic pole, the scattered developer can be sucked more efficiently.

[0033] According to the fifth aspect of the present invention, by providing the inlet port corresponding to the position where the developer of the developer holding member is likely to scatter, the developer can be sucked more efficiently.

[0034] According to the sixth aspect of the present invention, it is possible to perform suction without scattering the developer remaining inside the shielding member.

[0035] According to the seventh aspect of the present invention, compared with a structure in which a duct is separately provided, the number of parts can be reduced, the structure can be simplified, and the cost can be reduced.

[0036] According to the 8th scheme of the present invention, compared with a structure in which air is sucked from the downstream side of a shielding member in a developing device provided in an image forming device to recover the developer leaked from the shielding member, more efficient recovery of the developer remaining inside the limiting member and the shielding member of the developing device can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0038] Figure 1 A diagram for explaining an image forming apparatus to which this embodiment is applied;

[0039] Figure 2 is a perspective view showing the internal structure of the developer;

[0040] Figure 3 is a cross-sectional view showing the internal structure of the developer;

[0041] Figure 4 yes Figure 3 An enlarged view of the main parts of the developer is shown;

[0042] Figure 5It means from Figure 3 A diagram of the spatially continuous developer discharge path is shown.

[0043] Explanation of symbols

[0044] 1-image forming device, 1B-printing unit, 33-developer, 331-accommodating portion, 331a-opening portion, 332-developing roller, 333-pick-up roller, 334-first conveying portion, 335-second conveying portion, 336-third conveying portion, 337-limiting member, 337a-limiting roller, 337b-limiting scraper, 338-removing member, 339-cover, 339a-covering portion, 339b-guide piece, 50-space, 51-flow path, 52-flow path, 53-through hole, 54-suction pipe, 55-exhaust device, 56-fan, 60-housing, 61-support block. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0046] <Structure of image forming apparatus>

[0047] Figure 1 1 is a diagram for explaining an image forming apparatus 1 to which the present embodiment is applied. The image forming apparatus 1 according to the present embodiment includes a paper supply unit 1A, a printing unit 1B, and a paper discharge unit 1C. The paper supply unit 1A includes a first paper storage unit 11 to a fourth paper storage unit 14 for storing paper P as an example of a recording medium. The paper supply unit 1A is provided corresponding to the first paper storage unit 11 to the fourth paper storage unit 14, respectively, and is provided with discharge rollers 15 to 18 for delivering the paper P stored in each paper storage unit to a transport path connected to the printing unit 1B.

[0048] The printing unit 1B includes an image forming unit 20 for forming an image on a sheet of paper P. The printing unit 1B also includes a control unit 21 for controlling each unit of the image forming apparatus 1. The printing unit 1B also includes an image processing unit 22. The image processing unit 22 performs image processing on image data sent from the image reading device 4 or the personal computer (PC) 5. The printing unit 1B also includes a UI (User Interface) 23, which is composed of a touch panel or the like, and notifies information to the user and accepts input of information from the user.

[0049] The image forming unit 20 as an example of an image forming member is provided with six image forming units 30T, 30P, 30Y, 30M, 30C, and 30K (hereinafter, sometimes simply referred to as "image forming units 30") arranged in parallel at predetermined intervals. Each image forming unit 30 includes a photosensitive drum 31 that forms an electrostatic latent image while rotating in the direction of arrow A, a charging roller 32 that charges the surface of the photosensitive drum 31, a developer 33 that develops the electrostatic latent image formed on the photosensitive drum 31, and a drum cleaner 34 that removes toner and the like on the surface of the photosensitive drum 31.

[0050] The image forming unit 20 is provided with an exposure device 26 for exposing the photosensitive drum 31 of each image forming unit 30 with a laser beam. The exposure device 26 is not limited to the use of a laser beam for exposing the photosensitive drum 31. For example, a light source such as an LED (Light Emitting Diode) may be provided for each image forming unit 30, and the photosensitive drum 31 may be exposed using light emitted from the light source.

[0051] The image forming units 30 have the same structure except for the toner contained in the developer 33. The image forming units 30Y, 30M, 30C, and 30K form yellow (Y), magenta (M), cyan (C), and black (K) toner images, respectively. In addition, the image forming units 30T and 30P form toner images using toners corresponding to corporate colors, foaming toners for Braille, fluorescent toners, toners for improving gloss, and the like. In other words, the image forming units 30T and 30P form toner images using special color toners.

[0052] The image forming unit 20 is provided with an intermediate transfer belt 41 for transferring the toner images of each color formed on the photosensitive drum 31 of each image forming unit 30. The image forming unit 20 is provided with a primary transfer roller 42 for transferring the toner images of each color of each image forming unit 30 to the intermediate transfer belt 41 at the primary transfer unit T1. The image forming unit 20 is provided with a secondary transfer roller 40 for transferring the toner images transferred to the intermediate transfer belt 41 to the paper P at the secondary transfer unit T2. Furthermore, the image forming unit 20 is provided with a belt cleaner 45 for removing the toner and the like on the surface of the intermediate transfer belt 41, and a fixing device 80 for fixing the secondary transferred image to the paper P.

[0053] The image forming section 20 performs image forming operation according to a control signal from the control section 21. Specifically, in the image forming section 20, first, the image data input from the image reading device 4 or the PC 5 is subjected to image processing by the image processing section 22, and the image data after 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 roller 32, the photosensitive drum 31 is irradiated with a laser beam modulated by the image data obtained from the image processing section 22 by the exposure device 26.

[0054] Thus, an electrostatic latent image is formed on the photosensitive drum 31. The formed electrostatic latent image is developed by the developer 33, so that a magenta toner image is formed on the photosensitive 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.

[0055] The toner images of the respective colors formed in the respective image forming units 30 are electrostatically transferred to the primary transfer rollers 42 in sequence. Figure 1 The toner image overlapped on the intermediate transfer belt 41 is formed on the intermediate transfer belt 41 rotating in the direction of arrow C. The overlapped toner image formed on the intermediate transfer belt 41 is conveyed to the secondary transfer portion T2 composed of the secondary transfer roller 40 and the backup roller 49 as the intermediate transfer belt 41 moves.

[0056] On the other hand, after the paper P is taken out from the first paper storage portion 11 by the delivery roller 15, for example, it is transported to the position of the registration roller 74 through the transport path. When the superimposed toner image is transported to the secondary transfer portion T2, the paper P is supplied from the registration roller 74 to the secondary transfer portion T2 at the timing. Then, the superimposed toner image is electrostatically transferred to the paper P at the secondary transfer portion T2 by the transfer electric field formed between the secondary transfer roller 40 and the backup roller 49.

[0057] Then, the paper P to which the superimposed toner image is electrostatically transferred is conveyed to the fixing device 80. In the fixing device 80, the paper P on which the unfixed toner image is formed is pressed and heated, and the toner image is fixed on the paper P. Then, the paper P subjected to the fixing process passes through the curl correction section 81 provided in the paper discharge unit 1C, and is conveyed to a paper stacking section (not shown).

[0058] <Structure of the Development Device 33>

[0059] Figure 2 and Figure 3 It is a diagram showing the internal structure of the developing device 33. Figure 2 So from Figure 1The front side of the printing unit 1B of the image forming apparatus 1 is shown ( Figure 1 The front side of the paper) toward the back side ( Figure 1 The three-dimensional view when observing the developer 33 in the direction of (the inner side of the paper in the figure) is a cross-sectional view after removing the front side. Figure 3 This is a diagram when the developer 33 is viewed from the front side toward the rear side, and is a cross-sectional view with the front side removed.

[0060] The developer 33 has a housing 331, which is composed of a frame body arranged adjacent to the photosensitive drum 31 and extending from the front side to the rear side of the printing unit 1B. The housing 331 is provided with an opening 331a at a position opposite to the photosensitive drum 31. The developing roller 332, the pickup roller 333, the first conveying part 334, the second conveying part 335, the third conveying part 336, the limiting member 337, and the removing member 338 are accommodated inside the housing 331 together with the developer. A cover 339 for suppressing the scattering of the developer is provided below the opening 331a of the housing 331. The components inside the housing 331 are long components having the same length and are arranged approximately in parallel. The developer accommodated in the housing 331 is composed of a mixture of a toner for forming an image and a carrier of magnetic particles for conveying the toner. In addition, the components including the housing 331 are covered by the housing 60. The developing device 33 is an example of a developing unit.

[0061] The developing roller 332 includes a cylindrical shaft member and a cylindrical sleeve covering the shaft member. The developing roller 332 is configured so that a part of the side surface is exposed from the opening 331a of the housing 331, and the exposed surface is opposed to the photosensitive drum 31. The shaft member of the developing roller 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 roller 332 uses the magnetic force of the shaft member to adsorb the developer to the surface of the sleeve, and by rotating the sleeve, the developer is transferred to the opening 331a, so that the toner is attached to the charged photosensitive drum 31, thereby developing the electrostatic latent image. In addition, the developing roller 332 is an example of a developer retainer.

[0062] The pickup roller 333 is arranged adjacent to the developing roller 332 in parallel. The pickup roller 333 includes a cylindrical shaft member and a cylindrical sleeve covering the shaft member. The shaft member has a magnetic force, and the sleeve rotates around the shaft member. The pickup roller 333 uses the magnetic force of the shaft member to attract the developer to the surface of the sleeve, and by rotating the sleeve, the developer is transported and transferred to the developing roller 332.

[0063] The first conveying part 334, the second conveying part 335, and the third conveying part 336 are screw conveyors having spiral blades around the rotation axis. The first conveying part 334, the second conveying part 335, and the third conveying part 336 are arranged inside the accommodating part 331 so that the rotation axis is parallel to the developing roller 332 and the pickup roller 333. The developer is stirred by rotating the first conveying part 334, the second conveying part 335, and the third conveying part 336 around the rotation axis, and the developer is conveyed in the direction along the rotation axis of each conveying part 334 to 336. Then, the developer is conveyed by the first conveying part 334, the second conveying part 335, and the third conveying part 336 in sequence with the rotation of the first conveying part 334, the second conveying part 335, and the third conveying part 336, and is supplied to the pickup roller 333 from the third conveying part 336.

[0064] The limiting member 337 is provided along the side surface of the developing roller 332 at the downstream side of the position where the developing roller 332 faces the pickup roller 333 and at the upstream side of the position where the developing roller 332 faces the photosensitive drum 31. Here, the downstream side and the upstream side are the downstream side and the upstream side in the rotation direction of the developing roller 332. The limiting member 337 scrapes the developer supplied from the pickup roller 333 and held on the surface of the developing roller 332, and limits it to a predetermined height. The developer scraped by the limiting member 337 is recovered into the interior of the storage portion 331 and returned to the conveying path formed by the first conveying portion 334, the second conveying portion 335, and the third conveying portion 336.

[0065] In more detail, the limiting member 337 includes a limiting roller 337a and a limiting scraper 337b which are arranged at a predetermined interval relative to the surface of the developing roller 332. The limiting roller 337a is a roller member whose axial direction is arranged parallel to the axial direction of the developing roller 332, and which presses the developer supplied from the pickup roller 333 to the developing roller 332 so that the developer becomes a predetermined height from the surface of the developing roller 332. The limiting scraper 337b is a scraper extending parallel to the axial direction of the developing roller 332, and which scrapes the developer at the end portion of the layer so that the layer of the developer pressed by the limiting roller 337a becomes a predetermined height. The developer scraped by the limiting scraper 337b falls downward from between the limiting roller 337a and the limiting scraper 337b, and is recovered into the interior of the accommodating portion 331.

[0066] The removal member 338 is provided along the side surface of the developing roller 332 at the downstream side of the position where the developing roller 332 and the photosensitive drum 31 are opposed. The downstream side is the downstream side in the rotation direction of the developing roller 332. The removal member 338 scrapes off the developer remaining on the surface of the developing roller 332 after the developing roller 332 supplies the developer to the photosensitive drum 31. The developer scraped off from the developing roller 332 by the removal member 338 is recovered into the interior of the accommodating portion 331 and returned to the conveying path constituted by the first conveying portion 334, the second conveying portion 335, and the third conveying portion 336.

[0067] The cover 339 is a member that suppresses exposure of the developing roller 332 at the opening 331a of the housing 331. The cover 339 is composed of a covering portion 339a that covers the surface of the developing roller 332 at a predetermined 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-like member having a cross section in an arc shape along the surface of the developing roller 332, and suppresses scattering of the developer by covering the surface of the developing roller 332. The edge of the guiding piece 339b on the upstream side of the covering portion 339a in the rotation direction of the developing roller 332 is arranged to be away from the developing roller 332. The guiding piece 339b is arranged parallel to the limiting scraper 337b of the limiting member 337 so as to cover the limiting scraper 337b at a predetermined interval. The cover 339 is an example of a shielding member. The developer dispersed from the surface of the developing roller 332 after passing through the limiting blade 337 b is discharged from a space S surrounded by the surface of the developing roller 332 , the covering portion 339 a , and the limiting blade 337 b through a gap between the guide piece 339 b and the limiting blade 337 b .

[0068] A support block 61 for supporting the housing 331 is provided inside the housing 60, and the housing 331 and the housing 60 are separated by the support block 61 to form a space 50. The space 50 is continuous from the front side to the rear side of the developer 33, and forms a gap between the cover 339 and the limiting scraper 337b and a discharge flow path (pipe) for discharging the developer flowing from the opening 331a to the outside of the housing 331.

[0069] <Discharge of the developer dispersed from the developing roller 332>

[0070] Figure 4 yes Figure 3 FIG. 3 is an enlarged view of the main part of the developer 33. Figures 2 to 4 The discharge of the developer scattered from the surface of the developing roller 332 will be further described. First, the conveyance of the developer by the developing roller 332 will be described.

[0071] The developing roller 332 is described as including a shaft member 332a having a magnetic force and a cylindrical sleeve 332b that can rotate around the shaft member 332a. The shaft member 332a of the developing roller 332 is provided with a plurality of magnetic poles 332c. Figure 4 In the example shown, five magnetic poles 332c are radially arranged in a semicircular portion on the side of the opening 331a of the receiving portion 331 in the cross section of the shaft member 332a. These magnetic poles 332c are arranged so that adjacent magnetic poles 332c have opposite polarities. Figure 2) The developer supplied is attracted to the sleeve 332b by the magnetic field generated by the magnetic pole 332c, and is transported toward the opening 331a as the sleeve 332b rotates.

[0072] Here, the toner contained in the developer is transported by the first transport section 334, the second transport section 335, and the third transport section 336, and is charged during the stirring process. Furthermore, the developing roller 332 is opposed to the photosensitive drum 31 charged with a polarity different from that of the toner at the opening 331a. Therefore, if the developer is transported by the rotation of the sleeve 332b and reaches the opening 331a, the toner contained in the developer is adsorbed on the photosensitive drum 31. Then, the developer containing the carrier and the toner remaining without being adsorbed on the photosensitive drum 31 is further transported by the rotation of the sleeve 332b and returned to the accommodating section 331, and is removed by the removing member 338 (refer to Figure 2 ) is scraped off from sleeve 332b.

[0073] As described above, the developer is conveyed on the surface of the developing roller 332, but in the process, a part of the developer attached to the developing roller 332 is dispersed on the downstream side of the limiting member 337 in the rotation direction of the developing roller 332. For example, a part of the developer scraped by the limiting scraper 337b passes over the limiting scraper 337b and reaches the space S. In addition, the layer of the developer scraped by the limiting scraper 337b is sometimes dispersed due to the action of the sleeve 332b or the contact with the surface of the cover 339 facing the developing roller 332. The developer dispersed from the developing roller 332 is suspended in the space S, or scattered to the outside from the end of the cover 339 on the downstream side (opening 331a side) in the rotation direction of the developing roller 332. Therefore, a structure is provided to allow the developer dispersed from the developing roller 332 to flow in and be discharged.

[0074] Specifically, the gap between the cover 339 and the housing 60 of the developer 33 is used as a flow path for sucking and discharging the developer scattered from the opening 331a side of the cover 339 (see Figure 4 The flow path is referred to as "flow path 51". Flow path 51 is an example of the first flow path. In addition, a gap is provided between the guide piece 339b of the cover 339 and the limiting scraper 337b to form a flow path for discharging the developer suspended in the space S (see FIG. 1 ). Figure 4 The flow path is referred to as "flow path 52". Flow path 52 is an example of a second flow path. The developer dispersed from the developing roller 332 is guided to the space 50 through the two flow paths 51 and 52 (refer to Figure 3 ) and discharged.

[0075] <Structure of developer discharge passage>

[0076] Next, refer to Figure 3 and Figure 4 The structure of the developer discharge flow path including the flow paths 51 and 52 is described. 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 roller 332. The two flow paths 51 and 52 merge in the middle and are connected to the space 50. The space 50 constitutes the flow path and is connected to the exhaust device, and the air is sucked by the exhaust device to constitute the flow path of the air from the flow paths 51 and 52 through the space 50 to the exhaust device. With the flow of the air, the developer suspended in the space S and the vicinity of the opening 331a flows into the flow paths 51 and 52 and is discharged through the space 50. The flow path and the exhaust device including the space 50 will be described later.

[0077] If we compare flow path 51 and flow path 52, Figure 4 In the cross section shown, the flow path 52 is narrower than the flow path 51. Therefore, if air is sucked from the space 50 where the flow paths 51 and 52 merge, the negative pressure of the flow path 52 is higher than that of the flow path 51. With this structure, the developer suspended or staying between the cover portion 339a of the cover 339 and the developing roller 332 is guided back to the upstream side in the rotation direction of the developing roller 332 and discharged from the flow path 52. As a result, more developer is sucked into the flow path 52, and the scattering of the developer on the opening portion 331a side is suppressed.

[0078] The inlet ports of the flow paths 51 and 52 are further described. Figure 4 As shown, the flow path 51 is composed of the outer side surface of the cover 339 and the inner side surface of the housing 60 of the developer 33. In addition, the inlet of the flow path 51 is formed by the end of the cover 339 on the downstream side (opening 331a side) in the rotation direction of the developing roller 332 and the end of the housing 60 on the opening 331a side. Thus, the developer that flies and suspends near the opening 331a over the cover 339 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.

[0079] The flow path 52 is formed by the surfaces of the guide piece 339b of the cover 339 and the limiting scraper 337b of the limiting member 337 facing each other. In addition, the inlet of the flow path 52 is formed at the end of the facing surface of the guide piece 339b and the limiting scraper 337b on the side of the space S. Thus, the developer dispersed from the developing roller 332 in the space S is sucked into the flow path 52 from the inlet of the flow path 52. The inlet of the flow path 52 is an example of a second inlet.

[0080] More specifically, the inlet of the flow path 52 is provided at a position on the surface of the developing roller 332 that is opposite to a portion between two adjacent magnetic poles 332c of the shaft member 332a of the developing roller 332. Figure 4In the example shown, the inlet of the flow path 52 is provided at a position opposite to the substantially central portion between two adjacent magnetic poles 332c. First, a case where the developer is adsorbed to the sleeve 332b by the magnetic field generated by the magnetic pole 332c on the surface of the developing roller 332 is described. Also, a case where the adjacent magnetic poles 332c are arranged to have opposite polarities to each other is described. Due to this structure, the developer adsorbed to the sleeve 332b forms a layer at the position of the magnetic pole 332c in a shape like a row of rice ears that are stacked from the surface of the sleeve 332b. Furthermore, if the developer is transported away from the magnetic pole 332c as the sleeve 332b rotates, the developer layer gradually falls in the direction of rotation of the sleeve 332b. If the sleeve 332b further rotates and the developer layer approaches the next magnetic pole 332c, the developer layer gradually rises in an inverted manner while the fallen end side is in contact with the surface of the sleeve 332b. In this process, since the magnetic field is weakened between the two magnetic poles 332c where the developer layer is in a fallen state, the developer is more likely to be dispersed from the surface of the sleeve 332b than when it is located on a certain magnetic pole 332c. Therefore, by setting the position of the inlet of the flow path 52 to a position opposite to the portion between the two adjacent magnetic poles 332c, the developer dispersed from the surface of the sleeve 332b can be efficiently flowed into the flow path 52.

[0081] Figure 5 It means from Figure 3 The space 50 shown is a diagram of a continuous developer discharge path. Figure 5 3 shows a portion of the rear side of the developing device 33, a suction pipe 54 connected to the developing device 33, and an exhaust device 55. Figure 5 In the figure, the space 50 is not shown, but the duct portion for allowing air to flow from the developing device 33 to the suction duct 54 is marked with a reference numeral 50. One end of the suction duct 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 duct 54 is connected to an exhaust device 55. The exhaust device 55 is, for example, disposed in the printing unit 1B of the image forming apparatus 1 (see Figure 1 ) on the back ( Figure 1 inside of the ).

[0082] The exhaust device 55 is provided with a fan 56, and the air in the space 50 of the developer 33 is sucked through the suction pipe 54 by rotating the fan 56. As a result, the suspended developer is sucked together with the air from the inlet 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 pipe 54. In addition, the exhaust device 55 is provided with a filter (not shown) to capture the developer discharged from the developer 33 together with the air. The space 50, the suction pipe 54, and the exhaust device 55 are an example of a suction unit.

[0083] Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above embodiments. Various changes or structural substitutions that do not depart from the scope of the technical concept of the present invention are included in the present invention.

[0084] <Note>

[0085] (1) A developing device, characterized in that it comprises: a developer retaining body for supplying developer to an image retaining body on which an electrostatic latent image is formed; a limiting member for limiting the amount of developer retained by the developer retaining body; a shielding member for covering a portion of the developer retaining body and the limiting member; and a suction portion, wherein in a covered area of ​​the developer retaining body covered by the shielding member, there is a first flow path for allowing air to flow in from a first inlet provided on the downstream side of an action of the developer retaining body and a second flow path for allowing air to flow in from a second inlet provided on the upstream side of an action of the developer retaining body, and air is sucked through the first flow path and the second flow path.

[0086] (2) The developing device according to (1), characterized in that:

[0087] The first flow path and the second flow path of the suction portion merge into one flow path in the middle.

[0088] (3) The developing device according to (1) or (2), characterized in that:

[0089] The second flow path is narrower than the first flow path.

[0090] (4) The developing device according to any one of (1) to (3), characterized in that:

[0091] The developer holding body includes a rotating developing sleeve and a magnet roller having a plurality of magnetic poles and arranged inside the developing sleeve, and the second inlet of the suction portion is arranged at a position opposite to a portion between the two magnetic poles of the developer holding body.

[0092] (5) The developing device according to (4), characterized in that:

[0093] The second inlet is provided at a position facing a substantially central portion between the two magnetic poles of the developer holding member.

[0094] (6) The developing device according to any one of (1) to (5), characterized in that:

[0095] The second flow path of the suction unit is set to have a higher negative pressure than the first flow path.

[0096] (7) The developing device according to any one of (1) to (6), characterized in that:

[0097] The second flow path of the suction portion is formed as a gap between the restriction member and the shielding member.

[0098] (8) An image forming apparatus comprising the developing device according to any one of (1) to (7).

[0099] According to the developing device of (1), compared with a structure in which air is sucked from the downstream side of the shielding member to recover the developer leaking from the shielding member, the developer remaining inside the regulating member and the shielding member of the developing device can be recovered more efficiently.

[0100] According to the developing device according to (2), compared with a structure in which a suction mechanism is provided for each flow path, the structure can be simplified and the cost can be reduced.

[0101] According to the developing device of (3), since the negative pressure of the second flow path is higher than that of the first flow path, the developer accumulated inside the shielding member can be sucked without scattering.

[0102] According to the developing device according to (4), compared with a configuration in which the inlet port is provided at a position corresponding to the magnetic pole, it is possible to efficiently suck the scattered developer.

[0103] According to the developing device of (5), by providing the inlet port corresponding to the position where the developer on the developer holding member is likely to scatter, the developer can be sucked more efficiently.

[0104] According to the developing device according to (6), it is possible to perform suction without scattering the developer remaining inside the shielding member.

[0105] According to the developing device involved in (7), compared with a structure in which a duct is separately provided, the number of parts can be reduced, the structure can be simplified, and the cost can be reduced.

[0106] According to the image forming apparatus involved in (8), compared with a structure in which air is sucked from the downstream side of the shielding member in the developing device to recover the developer leaked from the shielding member, it is possible to more efficiently recover the developer remaining inside the limiting member and the shielding member of the developing device.

[0107] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles and applications of the present invention. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A developing device, characterized in that: have: A developer holding body for supplying a developer to an image holding body on which an electrostatic latent image is formed; a limiting member for limiting the amount of the developer held by the developer holding body; a shielding member covering a portion of the developer holding body and the limiting member; and The suction portion has a first flow path for allowing air to flow in from a first inlet provided on the downstream side of the movement of the developer holding body, and a second flow path for allowing air to flow in from a second inlet provided on the upstream side of the movement of the developer holding body, in a covering area of ​​the developer holding body covered by the shielding member, and air is sucked through the first flow path and the second flow path.

2. The developing device according to claim 1, characterized in that: The first flow path and the second flow path of the suction portion merge into one flow path in the middle.

3. The developing device according to claim 1 or 2, characterized in that: The second flow path is narrower than the first flow path.

4. The developing device according to any one of claims 1 to 3, characterized in that: The developer holding body includes a rotating developing sleeve and a magnet roller having a plurality of magnetic poles and disposed 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 holding member.

5. The developing device according to claim 4, characterized in that: The second inlet is provided at a position facing a substantially central portion between the two magnetic poles of the developer holding member.

6. The developing device according to any one of claims 1 to 5, characterized in that: The second flow path of the suction unit is set to have a higher negative pressure than the first flow path.

7. The developing device according to any one of claims 1 to 6, characterized in that: The second flow path of the suction portion is formed as a gap between the restriction member and the shielding member. 8 . An image forming apparatus comprising the developing device according to claim 1 .

Images