JP5533017B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, or a multifunction machine thereof, and a developing device and a process cartridge installed therein.
In particular, at least two of the plurality of transport members that transport the developer in the longitudinal direction to form a circulation path are disposed so as to face the developer carrier, and upstream of the development region. In this regard, the present invention relates to a developing device, a process cartridge, and an image forming apparatus provided with the developer regulating member that regulates the developer amount below the developer carrier.

  2. Description of the Related Art Conventionally, a developing device containing a two-component developer (including a case where an additive or the like is added) composed of toner and a carrier is known in an image forming apparatus such as a copying machine or a printer. As a developing device of this type, a developing region in which at least two conveying members among a plurality of conveying members that convey the developer in the longitudinal direction are installed in the vertical direction, and the developer carrying member and the image carrying member face each other. For example, Patent Documents 1 to 3 describe a configuration in which a developer regulating member such as a doctor blade that regulates the developer amount on the upstream side of the developer is disposed below a developer carrier such as a developing roller.

  In a developing device using a two-component developer, toner is appropriately replenished into the developing device from a toner replenishing port provided in a part of the developing device according to toner consumption in the developing device. The replenished toner is agitated and mixed together with the developer in the developing device by a conveying member (agitating and conveying member) such as a conveying screw. Part of the stirred and mixed developer is supplied to the developer carrying member. The developer carried on the developer carrying member is regulated to an appropriate amount by a developer regulating member installed below the developer carrying member, and then the toner in the two-component developer is opposed to the image carrying member. To adhere to the latent image on the image carrier. A magnet is fixed inside the developing roller serving as the developer carrying member, and a plurality of magnetic poles are formed around the developing roller by the magnet.

  In the developing device described in Patent Document 1 or the like, a first conveying member (supply screw) and a second conveying member (collection screw) are installed in the vertical direction in the casing, and development is performed by these conveying members. This forms a circulation route for the agent. The first conveying member installed below supplies the developer to the developing roller at the position of the pumping magnetic pole while conveying the developer in the longitudinal direction. The second conveying member installed above conveys the developer separated from the developer roller at the position of the agent separating magnetic pole in the longitudinal direction (the direction opposite to the conveying direction by the first conveying member). The downstream side of the transport path (first transport path) by the first transport member and the upstream side of the transport path (second transport path) by the second transport member communicate with each other via the first relay unit. Then, the developer that has reached the downstream side of the first transport path stays at that position and is pushed up to reach the upstream side of the second transport path. Here, a toner supply port is provided on the upstream side of the second conveyance path, and new toner is appropriately supplied. In addition, the upstream side of the first transport path and the downstream side of the second transport path communicate with each other via the second relay unit. Then, the developer that has reached the downstream side of the second conveyance path falls by its own weight on the second relay unit and is moved to the upstream side of the first conveyance path.

  As described above, the developing device in which the plurality of conveying members are arranged in the vertical direction is more developed than the developing device in which the plurality of conveying members are arranged in the horizontal direction (see, for example, FIG. 19 of Patent Document 2). Since the apparatus can be made compact in the horizontal direction, a current feeding apparatus having such a configuration is often used in a tandem type color image forming apparatus in which a plurality of developing devices are arranged in parallel in the horizontal direction. In addition, a plurality of transport members are arranged in the vertical direction, and a developer supply path (first transport path) to the developer carrier and a developer recovery path (second transport path) that separates from the developer carrier. ) Is separated from the developing device in which a plurality of conveying members are arranged in parallel in the horizontal direction (for example, see FIG. 19 of Patent Document 2). Since the developer provided in step 1 does not easily include the developer after the development step, the density deviation of the toner image formed on the image carrier can be reduced.

  Further, in an image forming apparatus having a developing device in which a developer regulating member is disposed below the developer carrying member, a developing device in which the developer regulating member is disposed above the developer carrying member (for example, a patent) Compared with the apparatus equipped with the document 2 (see FIG. 19 and the like), it is possible to shorten the length of the sheet conveyance path from the sheet feeding unit (sheet accommodating unit) disposed below the image forming apparatus to the sheet discharge tray. In addition, the first print time in the tandem color image forming apparatus can be shortened. Furthermore, the layout in which the paper discharge tray is disposed above the image forming apparatus can be easily taken even if the paper transport path is relatively short, so that the tandem color image with a reduced horizontal size is provided. Often used in forming equipment.

  In the developing device in which a plurality of conveying members are arranged in the vertical direction, the weight is dropped by the second relay unit that connects the upstream side of the first conveying path and the downstream side of the second conveying path, and the developing is performed on the upstream side of the first conveying path. When the agent is moved (especially at high speed in a high speed machine), the increase in the agent pressure to the screw bearing seal part at the end of the conveying path increases, so a screw in the direction opposite to the conveying direction is placed at the downstream end of the second conveying path. Provided. However, if a screw is provided in the direction opposite to the conveyance direction, the developer jumps upward in the vicinity of the opposing portion of the screws facing each other in the conveyance direction, resulting in a decrease in conveyance efficiency. Further, when an image having a large image area is continuously output, a large amount of toner is consumed, so that a large amount of replenishment toner is conveyed in proportion thereto. Also in this case, the toner is wound up, and the scattered toner may leak from the peripheral seal portion.

  In particular, it has a first conveying member and a second conveying member arranged side by side in the vertical direction, and conveys the developer from the first conveying member (supply screw) to the developer carrying member so that the developer after development is first. This is because the one-way circulation type developing device that collects with the two conveying members (collecting screws) originally needs higher rotation than the conventional method in order to stabilize the developer conveyance (developer balance). There is a demand for a means for reducing the conveyance efficiency due to the developer splashing upward, and for the toner scattered from the peripheral seal portion.

  The present invention provides a developing device and a process cartridge that are capable of stable developer conveyance even during high-speed conveyance (high-speed machine) when the developer is circulated in one direction, and that improve problems such as toner scattering. For that purpose.

  An object of the present invention is to provide a small image forming apparatus that can stably convey a developer even during high-speed conveyance and that has improved problems such as toner scattering.

The developing device according to the present invention is disposed so as to face the image carrier, a developer carrier that carries the developer and supplies the developer to the image carrier, and is disposed so as to face the developer carrier. A developer regulating member that regulates the amount of the developer carried on the developer carrying member, and the developer carrying member that is disposed opposite to the developer carrying member and transports the developer in the longitudinal direction. A first conveying member to be supplied, and a second conveying member disposed above the first conveying member to face the developer carrying member and convey the developer detached from the developer carrying member in the longitudinal direction. The developer separated from the developer carrying member is carried on the developer carrying member again between the first carrying member and the second carrying member at a position facing the developer carrying member and the developer carrying member. And a receiving member from the second conveying member to the first conveying member. To powder transport direction downstream end of the region, it is characterized in that a plurality of fins of different shapes in the second conveying member and the opposite conveying direction are arranged.

  In the developing device according to the present invention, the plurality of fins have different mounting angles.

In the developing device according to the present invention, the plurality of fins are arranged at equal intervals in the circumferential direction, and a gap is provided between the fins when viewed from the axial direction of the second conveying member. .

  In the developing device according to the present invention, the plurality of fins are arranged on the same rotation circumference.

  In the developing device according to the present invention, the developer is a two-component developer composed of a toner and a carrier, and the carrier has a particle size of 20 to 60 μm.

  The process cartridge according to the present invention is characterized in that at least the image carrier and the developing device described above are integrated.

  An image forming apparatus according to the present invention includes any one of the above developing devices or process cartridges.

  According to the present invention, a plurality of fins having different shapes in the transport direction opposite to the second transport member are arranged at the downstream end portion in the agent transport direction in the transfer region from the second transport member to the first transport member. Therefore, it is possible to change the transport direction by dispersing the developer pressure transported at high speed. For this reason, the increase of the agent pressure to the screw bearing seal portion at the end of the conveyance path is prevented, and even when a large amount of replenishment toner is conveyed as in the case of continuously outputting an image with a large image area, the toner is wound up. As a result, leakage of scattered toner from the peripheral seal portion can be extremely reduced, and stable developer conveyance is possible even during high-speed conveyance. Therefore, an image forming apparatus including such a developing device or a process cartridge in which the developing device and the image carrier are integrated can obtain a small and good image.

1 is a schematic diagram of a configuration example of an image forming apparatus to which the present invention is applied. It is a perspective view which shows one structural example of the developing device which concerns on this invention. 1 is a cross-sectional view of a developing device according to the present invention. It is a figure explaining the function of a development image carrier. It is a top view of the developing device according to the present invention. It is the schematic explaining the structure of the circulation and the several fin of the developer in the image development apparatus concerning this invention. It is sectional drawing explaining the example of 1 structure of the process cartridge which concerns on this invention. (A) is a top view which shows the structure of a 1st conveying member, (b) is a top view which shows the structure of the 2nd conveying member provided with the several fin, (c) is a conventional 2nd conveying member. It is a top view which shows a structure. (A) is an enlarged view of the vicinity of a plurality of fins, and (b) is a view of the plurality of fins viewed from the axial direction. (A) is a figure which shows the angle of the fin vicinity, (b) is a figure which shows the conveyance direction of the developer by a fin, (c) is a figure which shows the conveyance direction of the developer by a fin different from (b). is there. It is a figure which shows the Example which combined the angle of the several fin.

  Embodiments of the present invention will be described with reference to the drawings. First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG. 1, and then the developing device and process cartridge will be described. In the embodiment, when a member related to a specific color and toner is described, alphabets of Y (yellow), M (magenta), C (cyan), and K (black) indicating the color of the toner are numbers. However, in the case of general explanation, the symbols Y, M, C, and K for identifying the toner color are omitted.

  In FIG. 1, reference numeral 1 denotes an apparatus main body of a tandem type color copying machine as an image forming apparatus, reference numeral 3 denotes a document conveying section for conveying a document to a document reading section, reference numeral 4 denotes a document reading section for reading image information of the document, Reference numeral 5 denotes a paper discharge tray on which output images are stacked, reference numeral 7 denotes a paper feed unit that accommodates a recording medium P such as transfer paper, reference numeral 9 denotes a registration roller that adjusts the conveyance timing of the recording medium P, and reference numerals 11Y and 11M. , 11C, and 11K are photosensitive drums as image carriers on which toner images of the respective colors are formed, and reference numerals 13Y, 13M, 13C, and 13K denote electrostatic latent images formed on the photosensitive drums 11Y, 11M, 11C, and 11K, respectively. Development devices 14Y, 14M, 14C, and 14K for developing the images transfer the toner images formed on the photosensitive drums 11Y, 11M, 11C, and 11K on the recording medium P in an overlapping manner. It is shown shooting bias roller (primary transfer bias rollers), respectively.

  Reference numeral 17 denotes an intermediate transfer belt on which toner images of a plurality of colors are transferred in an overlapping manner, reference numeral 18 denotes a secondary transfer bias roller for transferring the color toner image on the intermediate transfer belt 17 onto the recording medium P, and reference numeral 20 denotes a recording. Fixing devices 28Y, 28M, 28C, and 28K for fixing an unfixed image on the medium P correspond to developing devices 13Y, 13M, 13C, and toners (toner particles) of the respective colors (Y, M, C, and K). Each color toner container supplied to 13K is shown.

  Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.

  A document (not shown) is transported from the document table by the transport roller of the document transport unit 3 and placed on the contact glass of the document reading unit 4. The document information placed on the contact glass is optically read by the document reading unit 4. Specifically, the document reading unit 4 scans an image of a document on the contact glass while irradiating light emitted from an illumination lamp. Then, the light reflected from the original is imaged on the color sensor via the mirror group and the lens. The color image information of the original is read for each color separation light of RGB (red, green, blue) by the color sensor, and then converted into an electrical image signal. Further, color conversion processing, color correction processing, spatial frequency correction processing, and the like are performed by the image processing unit based on the RGB color separation image signals to obtain yellow, magenta, cyan, and black color image information.

  Image information of each color of Y, M, C, and K (yellow, magenta, cyan, and black) is transmitted to a writing unit (not shown). Laser light based on the image information of each color is emitted from the writing unit toward the corresponding photosensitive drums 11Y, 11M, 11C, and 11K.

  On the other hand, the four photosensitive drums 11Y, 11M, 11C, and 11K rotate clockwise in FIG. The surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K are uniformly charged at the facing portions of the charging portions 12Y, 12M, 12C, and 12K, respectively (charging process). Thus, a charging potential is formed on the photoconductive drums 11Y, 11M, 11C, and 11K. Thereafter, the charged surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K reach the irradiation positions of the respective laser beams.

  In the writing unit, laser beams corresponding to the image signals are emitted from the four light sources corresponding to the respective colors. Each laser beam passes through a different optical path for each color component of yellow, magenta, cyan, and black (exposure process).

  The laser beam corresponding to the yellow component is irradiated on the surface of the first photosensitive drum 11Y from the left side in FIG. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 11Y by a polygon mirror that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11Y charged by the charging unit 12.

  Similarly, the laser beam corresponding to the magenta component is irradiated on the surface of the second photosensitive drum 11M from the left in FIG. 1, and an electrostatic latent image corresponding to the magenta component is formed. The cyan component laser light is applied to the surface of the third photosensitive drum 11C from the left in FIG. 1 to form an electrostatic latent image of the cyan component. The black component laser light is applied to the surface of the fourth photosensitive drum 11K from the left in FIG. 1 to form an electrostatic latent image of the black component.

  Thereafter, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K on which the electrostatic latent images of the respective colors are formed reach positions facing the developing devices 13Y, 13M, 13C, and 13B, respectively. Then, each color toner is supplied from each developing device onto the photosensitive drums 11Y, 11M, 11C, and 11K, and the latent image on each photosensitive drum is developed (developing step).

  Thereafter, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K after the development process reach the facing portions of the intermediate transfer belt 17, respectively. Here, transfer bias rollers 14 </ b> Y, 14 </ b> M, 14 </ b> C, and 14 </ b> K are respectively installed at the facing portions so as to contact the inner peripheral surface of the intermediate transfer belt 17. Then, the toner images of the respective colors formed on the photosensitive drums 11Y, 11M, 11C, and 11K are sequentially superimposed and transferred onto the intermediate transfer belt 17 at the positions of the transfer bias rollers 14Y, 14M, 14C, and 14K. (Primary transfer step).

  The surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K after the transfer process reach positions facing the cleaning unit 15 shown in FIG. The untransferred toner remaining on the photosensitive drums 11Y, 11M, 11C, and 11K is collected by the cleaning unit 15 (cleaning process). Thereafter, the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11K pass through a charge removal unit (not shown), and a series of image forming processes on the photoconductor drums 11Y, 11M, 11C, and 11K is completed.

  On the other hand, the intermediate transfer belt 17 on which the toners of the respective colors on the photosensitive drums 11Y, 11M, 11C, and 11K are transferred (carried) are run counterclockwise in FIG. Reach the opposite position. The color toner image carried on the intermediate transfer belt 17 is transferred onto the recording medium P at a position facing the secondary transfer bias roller 18 (secondary transfer step).

  Thereafter, the surface of the intermediate transfer belt 17 reaches the position of an intermediate transfer belt cleaning unit (not shown). Then, the untransferred toner attached on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit, and a series of transfer processes in the intermediate transfer belt 17 is completed.

  Here, the recording medium P conveyed to the secondary transfer nip formed between the intermediate transfer belt 17 and the secondary transfer bias roller 18 was conveyed from the paper supply unit 7 via the registration roller 9 and the like. Is. Specifically, the recording medium P fed by the paper feeding roller 8 from the paper feeding unit 7 that stores the recording medium P is guided to the registration roller 9 after passing through the conveyance guide. The recording medium P that has reached the registration roller 9 is conveyed toward the secondary transfer nip at the same timing.

  The recording medium P onto which the full color image has been transferred is then guided to the fixing device 20. In the fixing device 20, the color image is fixed on the recording medium P at the nip between the fixing roller and the pressure roller. The recording medium P after the fixing process is discharged as an output image outside the apparatus main body 1 by a discharge roller and stacked on the discharge tray 5 to complete a series of image forming processes.

In this embodiment, among these constituent members, as shown in FIG. 7, the photosensitive drum 11, the charging unit 12, the developing device 13, the cleaning unit 15, and the brush roller 61 that supplies the lubricating member 62 to the photosensitive drum, The process unit 60 is configured by being integrated for each color.
(Configuration of representative example)
2 is a perspective view of the developing device 13 according to the present invention, FIG. 3 is a sectional view of the process unit 60 according to the present invention on the developing device 13 side, FIG. 4 is a diagram for explaining the action of magnetic force of the developing device, and FIG. FIG. 6 is a plan view of the developing device 13, and FIG. 6 is a diagram showing the flow of the developer in the developing device. Since the developing devices 13Y, 13M, 13C, and 13K corresponding to the respective colors have the same configuration except for the toner color, the symbols Y, M, C, and K for identifying the toner color are omitted here. A single developing device will be described using only numerals.

  The configuration and operation of the developing device 13 to which the present invention is applied will be described with reference to FIGS. In the developing device 13, a two-component developer G having a carrier and toner is accommodated in a casing 50 of the developing device 13, and a latent image formed on the photosensitive drum 11 is converted into toner of the developer G. It develops with. The developing device 13 is opposed to the photosensitive drum 11 and is provided with a developing sleeve 51 serving as a developer carrying member having a plurality of magnetic poles formed around it, and disposed below the developing sleeve 51 so as to face the sleeve. In addition, a doctor blade 52 serving as a developer regulating member that regulates the amount of developer carried on the developing sleeve 51, and a plurality of transports for transporting the developer G accommodated in the casing 50 in the longitudinal direction of the developing sleeve 51. A member is provided. The plurality of conveying members are opposed to the developing sleeve 51 in the casing 50 and are supplied as a first conveying member that supplies the developer G to the developing sleeve 51 while conveying the developer G in the longitudinal direction of the developing sleeve 51. A second screw 53 is disposed above the supply screw 53 so as to face the developing sleeve 51 in the casing 50 and conveys the developer G detached from the developing sleeve 51 in the longitudinal direction of the developing sleeve 51. When it becomes a conveyance member, it is comprised with the collection | recovery screw 54. FIG.

  A partition member 57 is disposed between the supply screw 53 and the recovery screw 54 at a position facing the developing sleeve 51 to prevent the developer detached from the developing sleeve 51 from reattaching to the developing sleeve 51. Has been. Inside the casing 50, the partition member 57 is divided into a first transport path 531 in which the supply screw 53 is disposed and a second transport path 541 in which the recovery screw 54 is disposed.

  As shown in FIG. 6, the first transport path 531 and the second transport path 541 communicate with each other on the downstream side of the supply screw 53 and the upstream side of the recovery screw 54 via the first relay unit 56, and upstream of the supply screw 53. And a downstream side of the recovery screw 54 via the second relay portion 58. The developer G that has reached the downstream side of the supply screw 53 stays at that position and is pushed up by the rotation of the supply screw 53 and reaches the upstream side of the second transport path 541 via the first relay unit 56. A toner replenishing port 542 is provided on the upstream side of the second transport path 541, and new toner is appropriately replenished. Further, the developer G that has reached the downstream side of the second transport path 541 falls by its own weight on the second relay portion 58 and is moved to the upstream side of the first transport path 531. 3 and 6, reference signs A and B indicate the transport direction of the developer G, respectively.

  The developing device 13 is filled with 300 g of a developer G in which toner (5.8 μm) containing a polyester resin as a main component and a carrier (35 μm) which is a magnetic fine particle are uniformly mixed in 7 wt%, and is arranged in parallel with each other. By rotating the supplied screw 53 and the collecting screw 54 at 600 rpm, the toner is stirred and conveyed after replenishment at the same time, and the toner and carrier are uniformly mixed and charged. As shown in FIG. 4, the uniformly mixed developer G is supplied to the surface of the outer peripheral portion of the sleeve by the magnetic force P5 of the mag roller 55 contained in the developing sleeve 51 from the supply screw 53 provided in parallel to the developing sleeve 51. When the developing sleeve 51 is rotated in the direction of the arrow in the drawing, the developing sleeve 51 is carried to a developing region formed by the photosensitive drum 11 and the developing sleeve 51, and a developing electric field is generated by a high voltage power source (not shown), whereby toner is transferred to the photosensitive member. The latent image on the drum 11 is developed. The developed developer G is introduced into the second transport path 541 by the magnetic force P3 of the mag roller 55 as the developing sleeve 51 rotates, and is transported in the longitudinal direction of the recovery screw 54 and recovered. .

  FIG. 6 shows the developer accumulation state in the developing device 13 during the operation of the present invention (during image output). The casing 50 having the supply screw 53 and the recovery screw 54 is filled with 300 g of developer G. For this reason, the developer G stirred and conveyed is conveyed and supplied from below to the developing sleeve 51 from the supply screw 53. The developed developer G is recovered above the supply screw 53 by the recovery screw 54. Therefore, the developer G accumulation state in the second conveyance path 541 (stirring conveyance path) where the recovery screw 54 is arranged is inclined obliquely over the longitudinal direction of the development sleeve 51 as shown by the black portion in FIG. doing.

  On the upstream side of the second relay portion 58 in the transfer region from the recovery screw 54 to the supply screw 53, the downstream end portion 54 a in the transport direction of the recovery screw 54 (the downstream end portion of the second transport path 541) A rotating member 201 having a plurality of fins having different shapes in the conveying direction opposite to the recovery screw 54 is disposed. The rotating member 201 is provided coaxially with the collecting screw 54 at the downstream end 54 a of the collecting screw 54, and is configured to rotate simultaneously with the rotating operation of the collecting screw 54. The rotating member 201 is disposed on the outer side in the transport direction than the entire length of the developing sleeve 51 in the longitudinal direction, and is disposed on the outer side of the developer layer width. That is, the first relay unit 56 and the second relay unit 58 are disposed on the outer side in the transport direction than the entire length of the developing sleeve 51 in the longitudinal direction. A more ideal position of the rotating member 201 is preferably sufficiently outside the entire length of the developing sleeve 51 in the longitudinal direction.

  8A shows the shape of the supply screw 53 used in the present invention, FIG. 8B shows the shape of the recovery screw 54 used in the present invention with the rotating member 201 attached, and FIG. 8C shows the conventional recovery screw. Each of the five shapes is shown.

  The rotating member 201 attached to the recovery screw 54 includes a main body 202 attached to the downstream end 54a of the recovery screw 54 and the main body 202, as shown in FIGS. And six fins 201a, 201b, 201c, 201d, 201e, 201f having the same surface area. The fins 201 a, 201 b, 201 c, 201 d, 201 e, 201 f may be integrated with the recovery screw 54 by providing a slit or the like directly in the downstream end portion 54 a instead of the main body 202. Considering detachability, it is preferable to attach to the main body 202.

  As shown in FIG. 10A, the attachment angle h of each fin is an angle from a line L1 parallel to the axis of the recovery screw 54 to the inner surface of each fin. The attachment angle h is different for each fin, and the return direction of the conveyed developer is dispersed by changing the attachment angle h of each fin. The angle, pattern, and number of fins provided on the rotating member 201 are adjusted according to the developer fluidity and the set number of rotations of the collection screw 54. As shown in FIG. 9B, the plurality of fins 201a to 201f are arranged at equal intervals in the circumferential direction, and gaps S1 to S6 are provided between the fins when viewed from the axial direction of the recovery screw 54. Yes. FIG. 11 shows an example of a combination in which an experiment was conducted by optimizing the fin angle h by computer simulation.

  As described above, the downstream end portion 54 a of the recovery screw 54 located in the transfer region from the recovery screw 54 to the supply screw 53 has a plurality of fins 201 a to 201 f having different shapes in the conveying direction opposite to the recovery screw 54. Since the rotating member 201 is disposed, as shown in FIGS. 10B and 10C, it is possible to change the transport direction by dispersing the developer pressure transported at high speed. For this reason, the increase in the agent pressure to the screw bearing seal portion at the end of the conveyance path 541 is prevented, and even when a large amount of replenishment toner is conveyed as in the case of continuously outputting an image with a large image area, the toner As a result, the leakage of the scattered toner from the peripheral seal portion can be extremely reduced, and the developer G can be stably conveyed even during high-speed conveyance. Therefore, the developing device 13 and the image forming apparatus including the process cartridge 60 in which the developing device 13 and the photosensitive drum 11 are integrated are stable because the developer G is stably supplied while maintaining a small size. An image can be obtained.

  In addition, since the angles of the fin surfaces of the plurality of fins 201a to 201f are different from each other, the transport agent in the return direction different from the transport direction of the developer G transported to the terminal end side of the transport path 541 by the recovery screw 54. Since the transport direction can be dispersed, even when a lot of replenishment toner is transported, such as when the agent pressure rises to the screw bearing seal part at the end of the transport path or when an image with a high image area is continuously output, It is possible to more reliably prevent the toner from being rolled up and the scattered toner from leaking out (blowing out) from the peripheral seal portion.

  The plurality of fins 201a to 201f are arranged at equal intervals in the circumferential direction, and when viewed from the axial direction of the recovery screw 54, gaps S1 to S6 are provided between the fins, thereby preventing uneven rotation during rotation. Thus, when the recovery screw 54 rotates poorly, the locking phenomenon due to the increase in the end portion agent pressure during reverse rotation can be alleviated. Further, since the fins 201a to 201f are arranged on the peripheral surface of the main body 202, that is, are arranged on the same rotation circumference, the axial length can be made short and compact.

  In a color copying machine that is an image forming apparatus including the developing device 13 and the process cartridge 60 with such a configuration and operation, even if the printing speed is increased and the rotation measure of the recovery screw 54 is accordingly increased, In addition, the transport direction change range of the developer G transported at high speed in addition to this speed increase is not concentrated at one point, and a mechanism that can be realized in a space-saving manner can be provided.

  In addition, in Japanese Patent Application Laid-Open No. 2008-203814, which is a known technique, as shown in FIG. 16 and paragraph 0061, the excess developer is discharged by utilizing the developer jumping action at the boundary between the supply screw and the reverse screw. Although the function is established, in the present invention, the jumping action leads to a decrease in the conveyance efficiency. Therefore, a plurality of fins 201a to 201f are provided at the downstream end 54a of the recovery screw 54, and the developer G is set to one point. I tried to improve it by not concentrating.

  In the present embodiment, the image forming apparatus has been described as a color copying machine. However, a color facsimile, a color printer, or a combination of these can obtain the same effects.

11 (Y, M, C, K) image carrier 13 (Y, M, C, K) developing device 51 (Y, M, C, K) developer carrier 52 (Y, M, C, K) development Agent restricting member 53 (Y, M, C, K) First transport member 54 (Y, M, C, K) Second transport member 54a Downstream end 57 Partition member 60 Process cartridges 201a to 201f Multiple fins G Developer h Mounting angle S1 to S6 Gap

Japanese Patent Laid-Open No. 11-174810 JP 2008-26408 A Japanese Patent No. 3950735

Claims (7)

A developer carrier disposed opposite to the image carrier and carrying the developer and supplying the developer to the image carrier;
A developer regulating member that is disposed to face the developer carrying member and regulates the amount of the developer carried on the developer carrying member;
A first conveying member that is disposed opposite to the developer carrier and supplies the developer to the developer carrier while conveying the developer in the longitudinal direction;
A second conveying member that is disposed above the first conveying member and faces the developer carrying member, and conveys the developer released from the developer carrying member in the longitudinal direction;
At a position facing the developer carrying member, the developer detached from the developer carrying member is again carried on the developer carrying member between the first carrying member and the second carrying member. A partition member for preventing
A plurality of fins having different shapes in the conveying direction opposite to the second conveying member are disposed at the downstream end portion in the agent conveying direction in the transfer region from the second conveying member to the first conveying member. A developing device.   The developing device according to claim 1, wherein the plurality of fins have different attachment angles. The plurality of fins are arranged at equal intervals in the circumferential direction, and a gap is provided between the fins when viewed from the axial direction of the second conveying member. Development device.   The developing device according to claim 1, wherein the plurality of fins are arranged on the same rotation circumference.   The developing device according to claim 1, wherein the developer is a two-component developer including a toner and a carrier, and the particle size of the carrier is 20 to 60 μm.   A process cartridge in which at least an image carrier and the developing device according to claim 1 are integrated.   An image forming apparatus comprising the developing device according to claim 1 or the process cartridge according to claim 6.

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