JP2015129905A - Developing apparatus, image forming apparatus including the same, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing apparatus having a collection chamber arranged below a supply chamber, configured to ensure a strong air flow flowing through a lower case gap.SOLUTION: A developing apparatus separates developer 320 from a developing roller 302 after development, by means of a repulsive magnetic field to be generated by two separation magnetic poles (magnetic poles of magnets MG3, MG4) formed adjacent to each other in a developing-roller surface moving direction, and having the same polarity, to collect the developer into a collection chamber 305a. A gutter member 330 is arranged so that one end faces a developing roller surface part formed between positions P3, P4 where normal-direction magnetic densities of the two separation magnetic poles are maximized on the developing roller surface, at a predetermined distance, while the other end opposite the one end is arranged at a predetermined distance from an inner wall of a developing case 301 constituting the collection chamber 305a. The gutter member is arranged in a position so that a top face may receive at least a part of developer separating from the developing roller surface.

Description

  The present invention relates to a developing device that develops a latent image on a latent image carrier using a two-component developer composed of toner and a magnetic carrier, and an image forming apparatus and process such as a copying machine, a facsimile, and a printer equipped with the developing device. This relates to the cartridge.

  This type of developing device is generally a two-component developer (hereinafter simply referred to as “developer”) that is transported in a developer supply transport path extending in the direction of the rotation axis of the developer support along the developer support. ) Is carried on the surface of the rotating developer carrying member and conveyed to the developing region by the rotation of the developer carrying member.

  As the developing device, there is a supply / recovery separation system that collects the developed developer on the surface of the developer carrying member that has consumed toner in the developing region to a developer collecting / conveying path that is different from the developer supplying / conveying path. There is what is adopted (for example, Patent Document 1).

  In general, in order to prevent toner from scattering outside the developing device, the developing device has a developing case inside the developing device except for an opening for making a part of the surface of the developer bearing member face the latent image bearing member. The structure is isolated from the outside. Even in such a structure, since there is a gap between the surface of the developer carrying member and the developing case, the toner in the developer may be scattered outside the developing device through the gap. When the toner is scattered outside the developing device, the toner spread inside the image forming apparatus, for example, the recording material such as paper on which an image is finally formed becomes dirty, or the members or devices disposed inside the image forming apparatus Normal operation may be hindered. Therefore, it is an important problem to suppress the scattering of toner outside the developing device.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a supply / recovery separation type developing device in which a developer recovery transport path is disposed below the developer supply transport path. A developing device that secures the strength of the airflow flowing from the gap (lower case gap) between the developing case and the surface of the developer carrying member and hardly reduces the effect of suppressing toner scattering, and an image forming apparatus including the developing device And to realize a process cartridge.

  In order to achieve the above object, the present invention includes a magnetic field generating means having a plurality of magnetic poles including two magnetic poles adjacent to each other in the developer carrier surface movement direction and having the same polarity. A developer carrying body that carries the developer on the surface and moves the surface, and transports the developer to the developing area facing the surface of the latent image carrying body, and is supplied onto the surface of the developer carrying body A developer supply transport path for transporting the developer to be developed along the direction of the rotation axis of the developer carrier by the developer supply transport member, and the developer by the two magnetic poles at a position below the developer supply transport path. A developing device having a developing case in which a developer collecting / conveying path for collecting the developer separated from the surface of the carrying member and conveying the developer along a rotation direction of the developer carrying member by a developer collecting / conveying member is formed inside In One end of the two magnetic poles in the moving direction of the image carrier surface is spaced a predetermined distance from the surface of the developer carrier between portions where the normal direction magnetic flux density on the developer carrier surface is maximum. The other end side opposite to the one end side is provided with a developer guide member facing the inner wall of the developer case constituting the developer recovery transport path with a predetermined interval, The developer guide member is characterized in that the upper surface is disposed at a position for receiving at least a part of the developer separated from the surface of the developer carrier.

  According to the present invention, in the supply / recovery separation type developing device in which the developer recovery transport path is disposed below the developer supply transport path, the developer recovery transport path flows from the gap between the developing case and the developer carrier surface. An excellent effect is obtained in that the strength of the airflow can be secured and the reduction in the toner scattering suppression effect can be suppressed.

1 is a schematic configuration diagram of a printer according to an embodiment. 2 is a schematic configuration diagram of an image forming apparatus in the printer. FIG. FIG. 3 is an explanatory diagram of a developing device and a photoreceptor in which a normal magnetic flux density distribution on the surface of the developing roller is added. FIG. 6 is a cross-sectional explanatory diagram of a cross section parallel to the rotation axis direction of the developing roller. It is an internal perspective view of the principal part of the developing device. FIG. 2 is an external perspective view of a main part of the developing device. It is a schematic diagram explaining the flow of the developer in a developing case. FIG. 3 is a side sectional view of a section parallel to the rotation axis direction of the developing device. It is explanatory drawing of the communicating port part of the developing device. It is explanatory drawing which shows the flow of the developer peeled from the developing roller in the developing device. It is explanatory drawing for demonstrating the attachment method of the collar member provided in the developing device. FIG. 10 is an enlarged cross-sectional view of a main part of the developing device in Modification 1 when cut along a cross section perpendicular to the developing roller rotation axis direction. FIG. 10 is an explanatory diagram for explaining a movement path of a developer that moves between a collection chamber conveyance member and a collar member in the developing device according to the embodiment. FIG. 10 is an enlarged cross-sectional view when a main part of a developing device in Modification 2 is cut along a cross section orthogonal to a developing roller rotation axis direction. FIG. 10 is an explanatory diagram for explaining a movement of a developer that is peeled off from a developing roller in a developing device using a large-diameter developing roller. FIG. 10 is an explanatory diagram for explaining a movement of a developer that is peeled off from a developing roller in a developing device using a small-diameter developing roller. FIG. 10 is an enlarged cross-sectional view when a main part of a developing device according to Modification 3 is cut along a cross section orthogonal to a developing roller rotation axis direction. FIG. 10 is an enlarged cross-sectional view in the vicinity of a flange member of a developing device according to Modification 3.

Hereinafter, an embodiment in which the present invention is applied to a printer 100 as an image forming apparatus will be described.
FIG. 1 is a schematic configuration diagram of the printer 100.
The printer 100 according to the present embodiment is a color image forming apparatus that can form a full color image by adopting a tandem method, and each color of black, magenta, yellow, and cyan (hereinafter referred to as K, M, Y, and C). Image forming devices 17K, 17M, 17Y, and 17C for forming toner images are provided. Below these image forming devices 17K, 17M, 17Y, and 17C, the recording paper P is carried on the surface and conveyed around the downstream stretching roller 18 and the upstream stretching roller 19, and each image forming device is conveyed. A transfer conveying belt 15 is disposed as a recording material conveying member that moves on the surface while facing the devices 17K, 17M, 17Y, and 17C. Transfer bias rollers 5K, 5M, 5Y, and 5C that face the image forming devices 17K, 17M, 17Y, and 17C with the transfer conveyance belt 15 interposed therebetween are provided.

  Further, a fixing device 24 that fixes unfixed toner on the recording paper P separated from the transfer conveyance belt 15 is provided downstream of the downstream tension roller 18 in the recording paper conveyance direction by the transfer conveyance belt 15. . In addition, a discharge tray 25 for stacking recording paper P that has passed through the fixing device 24 and has a toner image fixed thereon is provided at the top of the main body of the printer 100.

  A plurality of paper feed cassettes 20 for storing the recording paper P are provided below the transfer conveyance belt 15. In addition, a paper feeding / conveying device 26 serving as a recording paper feeding unit that feeds the recording paper P from each paper feeding cassette 20 to a transfer region where the transfer / conveying belt 15 and the image forming devices 17K, 17M, 17Y, and 17C face each other. A registration roller pair 23 is provided that supplies the recording paper P conveyed from the paper cassette 20 in accordance with the image forming timings of the image forming devices 17K, 17M, 17Y, and 17C.

  In FIG. 1, the transfer conveyance belt 15 is disposed in an oblique direction so that the printer 100 is small in the left-right direction in FIG. 1, and the conveyance direction of the recording paper P indicated by an arrow A is an oblique direction. Accordingly, in the printer 100, the width of the housing in the left-right direction in FIG. 1 is slightly longer than the length in the longitudinal direction of the A3 size recording paper. That is, the printer 100 is greatly reduced in size by being the minimum size required to accommodate the recording paper therein.

  Each of the image forming devices 17K, 17M, 17Y, and 17C includes drum-shaped photosensitive members 1K, 1M, 1Y, and 1C as latent image carriers. There are charging devices 2K, 2M, 2Y, 2C, developing devices 3K, 3M, 3Y, 3C, cleaning devices 6K, 6M, 6Y, 6C, etc. in order with respect to the rotation direction of the photoreceptors 1K, 1M, 1Y, 1C. doing. Further, writing is performed from the exposure devices 16K, 16M, 16Y, and 16C on the surfaces of the photoreceptors 1K, 1M, 1Y, and 1C between the charging devices 2K, 2M, 2Y, and 2C and the developing devices 3K, 3M, 3Y, and 3C. This is a known configuration in which the incident light L is irradiated. The photoreceptors 1K, 1M, 1Y, and 1C may have a belt shape instead of a drum shape.

  In the printer 100 having such a configuration, each color toner image is formed by each of the image forming devices 17K, 17M, 17Y, and 17C at the start of image formation. In each of the image forming devices 17K, 17M, 17Y, and 17C, the photoconductors 1K, 1M, 1Y, and 1C are rotationally driven by a main motor (not shown) and are uniformly charged by the charging devices 2K, 2M, 2Y, and 2C. The exposure apparatus 16K, 16M, 16Y, and 16C irradiates the writing light L in accordance with the image information for each color obtained by color separation of the image, thereby forming an electrostatic latent image. The electrostatic latent images formed on the photoreceptors 1K, 1M, 1Y, and 1C are developed by the developing devices 3K, 3M, 3Y, and 3C, and toner images of the respective colors are formed on the surfaces of the photoreceptors 1K, 1M, 1Y, and 1C. Is formed. On the other hand, the recording paper P fed and conveyed from one of a plurality of paper cassettes 20 is transferred and conveyed by the registration roller pair 23 in accordance with the image forming timings of the image forming devices 17K, 17M, 17Y, and 17C. 15 on the surface. Then, the recording paper P carried on the transfer conveyance belt 15 is conveyed to the transfer area of each color by the surface movement of the transfer conveyance belt 15.

  The toner images formed on the photoconductors 1K, 1M, 1Y, and 1C are transferred to transfer bias rollers 5K, 5M, and 5Y, which are transfer units, at the facing portions of the photoconductors 1K, 1M, 1Y, and 1C and the transfer conveyance belt 15, respectively. , 5C are sequentially transferred onto the recording paper P carried on the transfer conveyance belt 15. In this way, the toner images formed on the respective photoreceptors 1K, 1M, 1Y, and 1C are transferred in the order of K (black), M (magenta), Y (yellow), and C (cyan), and are superimposed color. A toner image is formed on the recording paper P. The recording paper P onto which the toner image has been transferred is separated from the transfer conveyance belt 15 and conveyed to the fixing device 24 where the toner image is fixed and discharged to a paper discharge tray 25 outside the apparatus.

  On the other hand, after the toner image is transferred onto the recording paper P, the transfer residual toner is removed by the cleaning devices 6K, 6M, 6Y, and 6C, and the charge removal device (not shown) is removed as necessary. After neutralizing with the lamp, the operation of charging uniformly with the charging devices 2K, 2M, 2Y, 2C is repeated again.

  In the printer 100 shown in FIG. 1, four image forming apparatuses are arranged in the order of K (black), M (magenta), Y (yellow), and C (cyan) from the upstream side in the conveyance direction along the conveyance direction of the transfer conveyance belt 15. Although 17K, 17M, 17Y, and 17C are arranged, the order in which the image forming devices 17K, 17M, 17Y, and 17C for the respective colors are arranged is not limited to this. For example, a black image forming device 17K is arranged on the most downstream side in the transport direction, and four image forming devices 17 (M, Y) in the order of M (magenta), Y (yellow), C (cyan), and K (black). , C, K) may be arranged.

Next, the image forming device 17 will be described in detail.
The image forming devices 17K, 17M, 17Y, and 17C of the printer 100 according to the present embodiment use toners of different colors as image forming substances in the developing device 3, but have the same configuration except that. For this reason, hereinafter, the color-coded subscripts K, M, Y, and C will be omitted, and the image forming device 17 will be described.

FIG. 2 is a schematic configuration diagram of the image forming device 17 including the developing device 3 applicable to the printer 100 of the present embodiment.
The developing device 3 is disposed to face the photoconductor 1, and the photoconductor 1 is rotated in the clockwise direction in FIG. 2 as indicated by an arrow a in FIG. The charging device 2 is disposed above the photosensitive member 1 at a position of approximately 12:00 of the photosensitive member 1 in FIG. In this example, the charging device 2 is composed of a rotating body that is rotated at the same surface moving speed as that of the photosensitive member 1.

  The charging device 2 uniformly charges the surface of the photoconductor 1 in the dark, and then receives the writing light L from the exposure device 16 which is writing means (not shown) to form an electrostatic latent image. . The electrostatic latent image moves downstream as the photosensitive member 1 rotates and reaches the developing device 3. The developing device 3 is disposed on the right side of the photoreceptor 1. The developing device 3 includes, in the developing case 301, a supply chamber transport member 304 as a developer supply transport member that stirs and transports the developer 320, a recovery chamber transport member 305 as a developer recovery transport member, and development as a developer carrier. A rotating member such as a roller 302 and other members are provided.

  The developing roller 302 is disposed in the vicinity of the photosensitive member 1 at a position between 2 o'clock and 3 o'clock of the photosensitive member 1 in FIG. Closely arranged. A part of the developing case 301 corresponding to the part facing the photosensitive member 1 is opened to expose the developing roller 302. Here, the developing region α is a region where the developer 320 carried on the surface of the developing roller 302 is in contact with the surface of the photoreceptor 1.

  As the developing roller 302 moves in the direction of arrow b in FIG. 2, the developer 320 in the developing case 301 is carried on the surface of the developing roller 302 and is conveyed in the direction of arrow B in FIG. It is transported to α. The toner in the developer 320 adheres to the electrostatic latent image formed on the surface of the photoreceptor 1 in the development area α, and is visualized as a toner image. The toner image moves to the downstream side of the surface movement direction of the photoconductor 1 along with the rotation of the photoconductor 1, and reaches a transfer region β that is a portion facing the transfer bias roller 5 of the transfer device. The transfer bias roller 5 is disposed below the photoconductor 1 and at the 6 o'clock position of the photoconductor 1 in FIG. The transfer device of the present embodiment is configured to include the transfer bias roller 5 made of a rotating body as a transfer member, but the transfer member is not limited to the rotating body and may be a corona discharge type.

  The toner image on the photoreceptor 1 is transferred to the recording paper P in the transfer region β, and becomes an image on the recording paper P. The printer 100 according to the present embodiment is configured to directly transfer a toner image formed on the photoreceptor 1 onto the recording paper P. As a configuration for transferring the toner image formed on the photosensitive member 1 onto the recording paper P, the toner image on the photosensitive member 1 is temporarily transferred to an intermediate transfer member (such as an intermediate transfer belt), and each color toner image is transferred onto the intermediate transfer member. The developing device of the present invention is also applicable to an intermediate transfer body type image forming apparatus that forms a multi-color toner image by superimposing the images, and then transfers the multi-color toner image to a recording sheet all at once. In this case, the toner on the photoreceptor 1 is transferred to the intermediate transfer member (intermediate transfer belt) in the transfer region β.

  The surface of the photoreceptor 1 that has passed through the transfer region β moves to the downstream side in the surface movement direction along with the rotation of the photoreceptor 1 and reaches a portion facing the cleaning device 6. The cleaning device 6 is disposed at the 10 o'clock position with respect to the photoreceptor 1 in FIG. The cleaning device 6 removes the toner remaining on the surface of the photoreceptor 1 without being completely transferred onto the recording paper P in the transfer region β by the cleaning blade 601. The surface of the photoreceptor 1 that has passed through the portion facing the cleaning device 6 is then uniformly charged by the charging device 2, and the next image forming process is repeated.

  The developing device 3 of the present embodiment is combined with an image forming apparatus of a type that writes a latent image on the surface of the photoreceptor 1 with writing light L as shown in FIG. In order to uniformly apply negative charges on the surface of the photosensitive member 1 by the charging device 2 and to lower the negative potential, the image portion is exposed with the writing light L, and the image portion (electrostatic potential) in which the potential is lowered (static A so-called reversal development method is employed in which the latent image is developed with negative polarity toner. This is merely an example, and as a configuration to which the developing device including the characteristic portion of the present invention is applied, the polarity of the charged charge placed on the surface of the photoreceptor 1 is not a big problem.

Next, the developing device 3 will be described in detail.
As shown in FIG. 2, the developing device 3 includes a developing roller 302, a supply chamber conveying member 304, a collection chamber conveying member 305, and a developer regulating member 303 inside the developing case 301, and stirs and conveys the developer 320. Circulating. In the developing device 3 of the present embodiment, the supply chamber transport member 304 and the recovery chamber transport member 305 are screw members in which a helical screw blade is fixed to the rotating shaft, and the outer diameter of the screw blade is 16. [Mm] The following is used.

FIG. 3 is an explanatory diagram of the developing device 3 and the photosensitive member 1 in which the normal magnetic flux density distribution is additionally recorded on the surface of the developing roller 302.
As shown in FIG. 3, the developing roller 302 has therein a magnet roller 302d as magnetic field generating means in which a plurality of magnets MG (MG1 to MG5) are arranged in the circumferential direction, and the periphery thereof has a cylindrical developing sleeve. 302c rotates integrally with the rotating shaft 302e. The developing sleeve 302c is made of a nonmagnetic metal such as aluminum. The magnet roller 302d is fixed to a non-moving member, for example, the developing case 301 so that each magnet MG1 to MG5 faces a predetermined direction. In the developing roller 302, the developing sleeve 302c rotates around the magnet roller 302d that is a stationary member, and the developer 320 attracted by the magnet MG is carried on the surface of the developing sleeve 302c and conveyed. In this embodiment, in order to generate magnetic poles, independent magnets are arranged inside the developing roller. However, for example, a configuration in which five magnetic poles are magnetized on a magnetic roller may be used.

FIG. 4 is a cross-sectional explanatory diagram of a cross section parallel to the rotation axis direction of the developing roller 302.
As shown in FIG. 4, the developing roller 302 includes a fixed shaft 302 a fixed to a developing case 301 that is a stationary member, a magnet roller 302 d that is formed integrally with the fixed shaft 302 a, has a cylindrical shape, and a magnet The developing sleeve 302c covers the periphery of the roller 302d via a gap, and a rotating shaft 302e formed integrally with the developing sleeve 302c. The rotation shaft 302e is rotatable with respect to the fixed shaft 302a via a bearing 302f, and the rotation shaft 302e is driven to rotate by receiving power from a rotation driving means (not shown). As shown in FIG. 4, five magnets MG are fixed to the outer peripheral portion of the magnet roller 302d at a predetermined interval. The developing sleeve 302c rotates around these magnets MG.

  The five magnets MG arranged on the magnet roller 302d are for forming a magnetic field so that the developer 320 can be spiked on the peripheral surface of the developing sleeve 302c, and can be cut off. Magnetic carriers are gathered to form a magnetic brush so as to follow the lines of magnetic force emitted from these magnets MG. A magnetic field having a normal magnetic flux density distribution as shown in FIG. 3 is formed on the surface of the developing sleeve 302c by the five magnets MG1 to MG5 provided on the magnet roller 302d.

  In the developing device 3 of the present embodiment, the developing magnetic pole (N pole) is formed by the magnet MG1, and the transporting magnetic pole (S pole) for transporting the developed developer into the developing case is formed by the magnet MG2. Two stripping magnetic poles (both N poles) for stripping the subsequent developer are formed by the magnets MG3 and MG4, and a regulation magnetic pole facing the developer regulating member 303 is formed by the magnet MG5.

  In the development region α, the surface of the developing roller 302 and the surface of the photoreceptor 1 are not in direct contact with each other while maintaining a development gap GP that is a constant interval suitable for development. The developing device 3 causes the developer 320 to rise on the surface of the developing roller 302 by the developing magnetic pole, and the developer 320 is brought into contact with the photoreceptor 1, thereby attaching the toner to the electrostatic latent image on the surface of the photoreceptor 1. To visualize.

  A grounding bias power source (not shown) is connected to the fixed shaft 302 a constituting the developing roller 302 of the developing device 3. The voltage from the power source connected to the fixed shaft 302a is applied to the developing sleeve 302c through the conductive bearing 302f and the conductive rotating shaft 302e shown in FIG. On the other hand, the lowermost conductive support constituting the photoreceptor 1 is grounded. With such a configuration, an electric field for moving the toner separated from the carrier constituting the developer 320 to the photosensitive member 1 side is formed in the developing region α, and the static electricity formed on the surface of the developing sleeve 302 c and the photosensitive member 1 is formed. Due to the potential difference from the electrostatic latent image, the toner can be moved toward the photoreceptor 1 side.

  In the developing device 3, the developer 320 is pumped from the developer storage space ε onto the surface of the developing roller 302 by a magnetic field generated by the magnetic pole regulated by the magnet MG 5. Further, the developer 320 on the developing roller 302 is held from the position where the developer 320 is supplied from the developer storage space ε to the developing region α by the magnetic field generated by the restriction magnetic pole by the magnet MG5 and the developing magnetic pole by the magnet MG1. . Further, the developer 320 on the surface of the developing roller 302 from the developing region α to the inside of the developing case 301 is held on the developing roller 302 by the magnetic field generated by the developing magnetic pole by the magnet MG1 and the conveying magnetic pole by the magnet MG2. . Further, a separation region γ is formed in which the developer 320 on the surface of the developing roller 302 is peeled off by the magnetic field generated by the peeling magnetic pole generated by the magnet MG3, and the developer 320 is peeled off the developing roller 302 by the repulsive magnetic field generated by the peeling magnetic pole generated by the magnets MG3 and MG4. The developer 320 on the developing roller 302 is held. In the peeling region γ, the developer 320 is peeled from the developing roller 302 by the repulsive magnetic field generated by the peeling magnetic poles by the magnets MG3 and MG4.

  The developer 320 after development with the toner attached to the photoreceptor 1 has a reduced toner concentration. For this reason, if the developer 320 having a lowered toner density is transported again to the development area α without being separated from the developing roller 302 and used for development, there is a problem that the target image density cannot be obtained. End up. In order to prevent this, in the developing device 3, the developer 320 that has passed through the developing area α and carried on the surface of the developing sleeve 302c is separated from the developing roller 302 in the peeling area γ. The developer 320 separated from the developing roller 302 is collected in a collecting chamber 305a as a developer collecting / conveying path, and then sufficiently stirred and mixed in the developing case 301 so as to achieve a target toner concentration and toner charge amount. The

  In this way, the developer 320 having the target toner density and charge amount is supplied to the developer storage space ε from the supply chamber 304a as the developer supply transport path by the supply chamber transport member 304. At this time, in order to prevent the developer from being directly pushed into the developer storage space ε by the supply chamber conveying member 304 disposed above the developing roller 302, the developer storage space ε over the inflow prevention wall 311 is prevented. A device is devised so that the developer is supplied. The inflow prevention wall 311 is formed in a part of a partition plate 306 described later.

  The developer 320 supplied to the developer storage space ε is carried on the surface of the developing sleeve 302c by the magnetic force of the restricting magnetic pole by the magnet MG5, and with the developer restricting member 303 located immediately downstream of the peak position of the restricting magnetic pole. By passing through the facing portion, it is adjusted to a predetermined thickness. The developer 320 that has passed through the portion facing the developer regulating member 303 is conveyed to the development region α while forming a magnetic brush.

  FIG. 5 is an internal perspective view of a main part of the developing device 3, and FIG. 6 is an external perspective view of the main part of the developing device 3. FIG. 7 is a schematic diagram illustrating the flow of the developer 320 in the developing case 301 when the developing device 3 is viewed from the direction of arrow E in FIG. FIG. 8 is a cross-sectional explanatory view of the vicinity of the rotation axis of the supply chamber conveying member 304 when the developing device 3 is viewed from the direction of arrow E in FIG. FIG. 9 is an explanatory view of a portion provided with a communication hole in the partition plate 306 at both ends in the longitudinal direction of the developing device 3 as viewed from above. The arrows D1 to D4 in FIGS. 5 and 8 and the arrows in FIG. 7 indicate the flow of the developer 320 in the developing case 301.

  As shown in FIGS. 2 and 3, the supply chamber conveying member 304 is positioned around the developing roller 302 and is arranged in the 2 o'clock direction of the developing roller 302 in FIGS. 2 and 3. This position is also on the upstream side in the surface movement direction of the developing roller 302 with respect to the portion facing the developer regulating member 303. As shown in FIGS. 5 and 8, the supply chamber conveying member 304 has a screw shape with a spiral wing around the rotation axis, and is parallel to the developing roller center line O-302a of the developing roller 302. It rotates in the clockwise direction indicated by the arrow f in FIGS. 2 and 3 around the supply screw center line O-304. By this rotation, as shown by an arrow D4 in FIGS. 5 and 8, the developer 320 is agitated from the front side FS in the longitudinal direction of the developing device 3 toward the back side BS along the supply screw center line O-304. Transport while. That is, the supply chamber conveying member 304 conveys the developer 320 from the near side FS to the far side BS in the axial direction by inputting rotation driving to the rotation axis.

  As shown in FIGS. 2 and 3, the collection chamber transport member 305 is positioned around the developing roller 302 and in the vicinity of the separation region γ in the direction of 4 o'clock of the developing roller 302 in FIGS. Has been placed. As shown in FIGS. 5 and 8, the recovery chamber transport member 305 has a screw shape with a spiral wing (fin) around the rotation axis, and is parallel to the developing roller center line O-302a. The screw rotates in the counterclockwise direction indicated by the arrow g in FIGS. 2 and 3 around the screw center line O-305. By this rotation, as indicated by an arrow D2 in FIGS. 5 and 8, the developer 320 is agitated from the rear side BS in the longitudinal direction of the developing device 3 toward the front side FS along the recovery screw center line O-305. Transport while. That is, the recovery chamber transport member 305 transports the developer 320 from the back side BS opposite to the transport direction by the supply chamber transport member 304 toward the front side FS when the rotational drive is input to the rotation shaft.

  The supply chamber transfer member 304 is positioned above the recovery chamber transfer member 305, and a supply chamber 304 a that is a space around the supply chamber transfer member 304 in the developing case 301 and the recovery chamber transfer member 305. Is adjacent to the collection chamber 305a which is a space around the partition plate 306. As shown in FIGS. 5 and 6, the front side FS ends of the supply chamber transport member 304 and the collection chamber transport member 305 are positioned slightly in front of the front side FS ends of the developing roller 302. It is set. Thereby, the supply of the developer 320 from the supply chamber 304a to the end portion of the front side FS of the developing roller 302 is ensured. Further, the end portions on the back side BS of the supply chamber transfer member 304 and the collection chamber transfer member 305 are set to be located on the back side with respect to the end portion on the back side BS of the developing roller 302. As a result, a space for supplying toner, which will be described later, is secured. The length in the longitudinal direction of the developer regulating member 303 is set according to the length of the developing roller 302.

  As shown in FIGS. 2, 3, 7, and 8, a partition plate 306 that spatially partitions the supply chamber 304a and the recovery chamber 305a is provided between the supply chamber transfer member 304 and the recovery chamber transfer member 305. It is supported inside the developing case 301. Communication ports 41 and 42 are provided at both ends in the longitudinal direction of the partition plate 306, respectively. The developer 320 transported from the back side BS in the longitudinal direction to the near side FS by the collection chamber transport member 305 (arrow D2 in the figure) is cut off on the side wall of the developing case 301 at the end in the transport direction, so It rises along. The developer 320 that has reached the downstream end in the transport direction in the collection chamber 305a due to this swell is on the near side FS in the longitudinal direction of the communication ports provided at both ends in the longitudinal direction of the partition plate 306 described above. It passes through a lifting port 41 provided at the end of the head (arrow D3 in the figure) and is delivered to the supply chamber 304a.

  The developer 320 delivered to the supply chamber 304a is transported from the near side FS in the longitudinal direction to the back side BS by the supply chamber transport member 304 (arrow D4 in the figure). As in the case of the recovery chamber 305a, the developer 320 transported from the front side FS in the longitudinal direction to the back side BS by the supply chamber transport member 304 is cut off on the side wall of the developing case 301 at the end in the transport direction. . The developer 320 that has reached the downstream end portion in the transport direction in the supply chamber 304a reaches the end portion of the back side BS in the longitudinal direction among the communication ports provided at both end portions in the longitudinal direction of the partition plate 306 described above. It falls from the provided drop opening 42 and is delivered to the collection chamber 305a. The developer 320 delivered to the collection chamber 305a is again conveyed toward the near side FS by the collection chamber conveyance member 305 (arrow D2 in the figure).

  In the developing device 3 of this embodiment, the space between the supply chamber 304a and the recovery chamber 305a is partitioned by a partition plate 306. Therefore, only the developer 320 in which the toner and the carrier are sufficiently agitated and mixed is supplied to the developing roller 302 by the supply chamber conveying member 304. Further, the developer 320 whose toner density has been reduced immediately after development is exclusively stirred and conveyed by the collection chamber conveying member 305 and is not immediately supplied to the developing roller 302. Therefore, only the developer 320 including the toner having the target charge amount and having the target toner density is supplied to the developing roller 302 and used for development, so that high image quality can be obtained.

Next, toner supply in the developing device 3 will be described.
Since the developer 320 in the developing device 3 consumes toner while repeating the developing operation, it is necessary to supply the toner to the developer 320 in the developing device 3 from the outside of the developing device 3. The developing device 3 of the present embodiment includes a toner replenishing port 309 in the vicinity of the end of the back side BS in the longitudinal direction, and from the toner replenishing port 309, as indicated by an arrow T in FIGS. Supply toner. In the developing device 3 of the present embodiment, the vicinity of the end on the back side BS in the longitudinal direction is the vicinity of the end on the downstream side in the transport direction in the supply chamber 304 a that supplies the developer to the developing roller 302. For this reason, the toner replenished from the toner replenishing port 309 is not immediately used for development, but is supplied to the recovery chamber 305a through the dropping port 42.

  The toner supplied to the recovery chamber 305a together with the developer 320 is mixed and stirred with the developer 320 by the recovery chamber transport member 305, and is contained in the developer 320 having a predetermined toner concentration, from the lifting port 41. It is delivered to the supply chamber 304a and used for development. The collection chamber 305 a in which the collection chamber conveyance member 305 is disposed collects and conveys the developer 320 separated from the surface of the developing roller 302, and does not supply the developer 320 to the developing roller 302. For this reason, it is possible to prevent the developer 320 having a non-uniform toner density from being used for development in a state where the toner is not sufficiently agitated by newly supplying toner from the toner supply port 309. As a result, the developer 320 having a uniform toner density is used for development, and the image density can be stabilized.

  The toner replenished from the toner replenishing port 309 passes through the dropping port 42 and is supplied to the recovery chamber 305a. The front side FS in the longitudinal direction (in the direction of arrow D2 in the figure) while being agitated and mixed by the recovery chamber transport member 305 together with the developer 320 recovered in the recovery chamber 305a in a state where the toner concentration is reduced after being separated from the developing roller 302. It is conveyed toward. The newly replenished toner and the developer 320 whose toner concentration has decreased are transferred to the end of the front side FS of the developing device 3 that is the downstream end in the transport direction in the collection chamber 305a. The developer 320 has a normal density and is transferred from the lifting port 41 to the supply chamber 304a. In the supply chamber 304a, the developer 320 is supplied to the developing roller 302 and used for development while being transported by the supply chamber transport member 304 to the back side BS (in the direction of arrow D4 in the drawing) of the developing device 3 in the longitudinal direction.

  In the present embodiment, a region on the developing roller where a repulsive magnetic field is generated by two peeling magnetic poles formed by two magnets MG3 and MG4 having the same polarity adjacent to each other in the developing roller surface movement direction inside the developing roller (peeling) The developed developer transported to the region γ) is peeled off from the surface of the developing roller by the action of the repulsive magnetic field, and is collected in a collection chamber different from the supply chamber. Since such a supply / recovery separation system is employed, the toner concentration of the developer flowing through the supply path is maintained constant over the developer transport direction. Therefore, toner density unevenness does not occur in the developer carrier rotating shaft direction in the developer supplied to the development area.

Next, features of the present invention will be described.
As described above, it is an important problem to suppress the scattering of toner outside the developing device. As a method for suppressing the scattering of toner outside the developing device, it is effective to adopt a configuration in which outside air can flow toward the inner space of the developing case through the gap between the developing roller surface and the developing case. . Specifically, using the airflow generated when the developer after development that has passed through the development area is conveyed into the development case by the rotation of the development roller, the development case and the development into which the developed developer enters. An air flow toward the inner space of the developing case is generated in the gap of the roller. According to such a configuration, it is possible to suppress the scattering of the toner to the outside of the developing device due to the airflow flowing through the gap, or to collect the toner scattered to the outside of the developing device in the developing device.

  In the present embodiment, the developer 320 carried on the surface of the developing roller 302 that has passed through the developing region α is carried on the developing roller 302 by the magnetic force of the transport magnetic pole by the magnet MG2, and with the rotation of the developing roller 302. It is pulled into the developing case 301. Due to the rotation of the developing roller 302 and the movement of the developer accompanying the rotation of the developing roller 302, outside air is introduced into the space (lower case gap) CG between the surface of the developing roller 302 and the developing case inner wall. A suction air flow is generated. By generating such a suction air flow, the toner can be prevented from scattering outside the developing device 3, or the toner scattered outside the developing device 3 can be collected in the developing device. An inhibitory effect is obtained. The lower case gap CG is a gap (gap) where the edge (inner wall in the vicinity of the opening) of the developing roller and the developing case faces each other on the downstream side in the rotation direction of the developing roller from the developing region. is there.

  In particular, the magnet MG2 of the magnet roller 302d of the present embodiment is disposed so as to face the gap between the surface of the developing roller and the inner wall of the developing case 301. For example, the portion where the normal direction magnetic flux density of the magnet MG2 is maximized is disposed so as to face the gap with the inner wall of the developing case. For this reason, the developer on the developing roller rises in the gap by the magnetic field generated by the magnet MG2. In other words, the developer spiked in the developing region α by the magnetic field of the developing magnetic pole is transported with the rotation of the developing roller 302, and after having fallen into a sleeping state, is opposed to the transporting magnetic pole by the magnet MG 2. It shows a behavior that it is in a state of rising again in the vicinity of the position and then in a state of sleeping again. Due to such a behavior of the developer, a strong suction airflow is generated in the gap (lower case gap) CG between the surface of the developing roller 302 and the inner wall of the developing case, and a higher toner scattering suppressing effect is obtained.

  Here, as the strength of the airflow flowing through the lower case gap CG increases, the toner scattering suppression effect increases. However, the strength of the airflow greatly depends on the state of the airflow in the internal space of the developing case. Specifically, if part or all of the flow path of the airflow flowing from the lower case gap CG into the interior space of the developing case is blocked by the developer, the strength of the airflow flowing through the lower case gap CG is increased. Will become weaker. In particular, in the supply / recovery separation type developing device 3 in which the recovery chamber 305a is disposed below the supply chamber 304a, the developer separated in the separation region γ falls near the lower case gap CG.

  Referring to FIG. 15, the developer after development that has passed through the development region is a gap between the development case 301 and the surface of the development roller 302 as the development roller (developer carrier) 302 rotates. Lower case gap) is conveyed into the developing case through CG. Thereafter, the developer 320 after development is peeled off from the surface of the developing roller in the peeling region indicated by an arrow γ in the drawing under the action of a repulsive magnetic field by two magnetic poles having the same polarity, and falls into the developer collecting conveyance path. To do. In such a configuration, since the lower case gap CG is positioned below the peeling region, the developer 320 peeled from the peeling region γ falls near the lower case gap CG. It is easy to hinder the flow of air flowing in from the lower case gap CG.

  In particular, in recent years, with the demand for downsizing of the image forming apparatus, downsizing of the developing apparatus has been demanded, and in order to realize downsizing of the developing apparatus, reduction in the diameter of the developing roller 302 is desired. When the diameter of the developing roller 302 is reduced, in the supply and recovery separation type developing device in which the developer recovery transport path is disposed below the developer supply transport path, as shown in FIG. The agent 320 falls toward a position closer to the lower case gap CG, and the flow of airflow flowing from the lower case gap CG is likely to be hindered.

  Also in this embodiment, since the small-diameter developing roller 302 is used, as shown in FIG. 16, the developer peeled off in the peeling region γ may fall to a position closing the lower case gap CG. For this reason, the developer peeled off in the peeling region γ hinders the flow of the airflow flowing from the lower case gap CG, and there is a possibility that a sufficient toner scattering suppression effect cannot be obtained.

  Therefore, in the present embodiment, a collar member 330 as a developer guide member is provided in the collection chamber 305a. The flange member 330 is formed of a nonmagnetic material, for example, nonmagnetic SUS. The collar member 330 is a plate-like member and extends in the axial direction of the developing roller. Further, the developer is received on the upper surface of the collar member 330. By providing such a flange member 330, as shown in FIG. 10, it is possible to drop at least a part of the developer peeled off from the developing roller onto the flange member 330, and close to the lower case gap CG. It is possible to reduce the amount of developer falling on the surface. As a result, it is possible to suppress the developer peeled from the developing roller from inhibiting the momentum of the airflow flowing through the lower case gap CG and reducing the toner scattering suppression effect.

  In order to effectively prevent the momentum of the airflow flowing through the lower case gap CG from being hindered by the developer peeled from the developing roller, the flange member 330 according to the present embodiment moves the surface of the developing roller as shown in FIG. One end of the two-sided magnetic pole density by the two magnets MG3 and MG4 in the direction is opposed to the developing roller surface portion between the portions P3 and P4 where the normal magnetic flux density on the developing roller surface is maximum. Has been placed. In the present embodiment, one end portion is opposed to a place near the place P3 located on the upstream side of the developing roller surface movement direction among the places P3 and P4 on the developing roller surface. By doing so, it becomes possible to efficiently receive the developer separated between the places P3 and P4 by the flange member 330. In particular, when passing through a gap between the developing case 301 and the surface of the developing roller 302, a certain percentage (for example, 70%) or more of the developer is separated from the amount of developer carried on the developing roller. It is preferable to dispose the flange member 330 so that one end thereof faces the upstream side of the developing roller surface moving direction with respect to the position on the surface of the developing roller 302.

  Such an arrangement makes it possible to drop at least a part of the developer that is peeled off from the developing roller onto the collar member 330, and to reduce the amount of the developer that drops near the lower case gap CG. it can. As a result, it is possible to suppress the developer peeled from the developing roller from inhibiting the momentum of the airflow flowing through the lower case gap CG and reducing the toner scattering suppression effect. In this embodiment, the normal direction magnetic flux density of the surface portion of the developing roller facing one end of the collar member 330 is in the range of 27.5 to 37.5 mT.

  The eaves member 330 of the present embodiment is disposed so as to exist over substantially the entire recovery chamber 305a in the direction of the developing roller rotation axis. In the present embodiment, as shown in FIG. 11, protrusions 301b are provided on the lower surfaces of the developing case portion (partition plate 306) constituting the bottom of the supply chamber 304a in the vicinity of both ends in the developing roller rotation axis direction. . The flange member 330 of the present embodiment has its both ends in the developing roller rotation axis direction fixed to the protrusions 301b by caulking.

  The gap (interval) between the developing roller 302 and one end of the collar member 330 is at least such that the developer on the developing roller 302 conveyed along with the rotation of the developing roller 302 is not scraped by the collar member 330. It is desirable that the gap length be longer than the thickness of the developer passing through the gap. Preferably, a gap is formed between the developer passing through the gap and the flange member 330 so that the developer does not fill the gap even if the developer peeled off in the peeling region slightly falls. To be. In the present embodiment, the gap length of the gap is preferably 1.5 mm or more, and more preferably in the range of 2.0 mm or more and 3.5 mm or less. In this embodiment, the gap between the developing roller 302 and one end of the flange member 330 is 2.4 mm.

  Further, it is preferable that one end portion of the collar member 330 facing the surface of the developing roller 302 is located on the developing roller 302 side from a position directly above or just above the recovery screw center line O-305. When one end portion of the collar member 330 is located at a position farther from the developing roller 302 than the position directly above, the developer that has passed through the gap between the one end portion of the collar member 330 and the surface of the developing roller 302 is removed from the collection chamber conveyance member. This is because the possibility of being caught in rotation and accumulating in the lower case gap CG increases. In this case, since the developer accumulated in the gap CG inhibits the momentum of the airflow flowing through the gap CG, the toner scattering suppression effect is reduced.

  Further, the other end portion of the flange member 330 opposite to the one end portion is disposed to face the inner wall of the developing case 301 constituting the collection chamber 305a with a predetermined gap. With such an arrangement, the developer that has been peeled off from the developing roller and dropped onto the collar member 330 can be dropped from the gap into the collection chamber 305a. Since the developer falling from the gap falls to a position away from the gap CG between the surface of the developing roller 302 and the inner wall of the developing case, the influence on the airflow flowing through the gap CG is small. In this embodiment, the gap between the other end of the collar member 330 and the inner wall of the developing case is 3.7 mm. The gap length is such that the developer on the collar member 330 is fed to the recovery chamber 305a via the gap. It is set as appropriate so that it can fall smoothly.

  Here, as described above, the collection chamber transport member 305 of the present embodiment is configured by a screw member in which a fin having a spiral structure is provided on the rotation shaft, and the rotation shaft is indicated by an arrow in FIGS. 2 and 3. By rotating in the counterclockwise direction indicated by g, the developer in the collection chamber is conveyed in the direction of the rotation axis. At this time, in this embodiment, the conveyance force in the direction away from the developing roller 302 is applied to the developer present at the bottom of the collection chamber 305 a by the fins of the collection chamber conveyance member 305. Therefore, as shown in FIGS. 2 and 3, the developer in the recovery chamber 305 a is transported in the direction of the rotation axis of the recovery chamber transport member 305 in a state of being brought closer to the side away from the developing roller 302. As a result, the developer in the recovery chamber 305a can be moved away from the lower case gap CG, so that the internal space of the recovery chamber 305a adjacent to the lower case gap CG can be secured widely. As a result, the loss of momentum of the airflow flowing from the lower case gap CG into the recovery chamber 305a can be reduced, and a strong airflow can be generated by the lower case gap CG.

  However, in such a configuration, the developer is splashed up by the rotational drive of the recovery chamber transport member 305 at a position farther from the developing roller 302 than the recovery screw center line O-305. If the developer splashed up in this way moves to the lower case gap CG through the upper space of the recovery chamber 305a, the momentum of the airflow flowing through the lower case gap CG may be hindered.

  Therefore, in the present embodiment, the horizontal position of the other end of the collar member 330 is set to be on the side farther from the developing roller 302 than the recovery screw center line O-305. With this configuration, the position where the developer on the collar member 330 falls into the collection chamber 305a is a position on the side farther from the developing roller 302 than the collection screw center line O-305. Thereby, the developer falling from the collar member 330 can collide with the developer splashed up by the rotational drive of the collection chamber transport member 305, and the kinetic energy can be consumed. As a result, it is possible to reduce the amount of developer that is spun up by the rotational drive of the collection chamber transport member 305 and reaches the lower case gap CG, and the momentum of the airflow flowing through the lower case gap CG is obstructed. Can be suppressed.

  Further, in the present embodiment, in order to smoothly drop the developer on the collar member 330 from the gap between the other end of the collar member 330 and the inner wall of the developing case into the collection chamber 305a, the upper surface of the collar member 330 is the gap. You may comprise so that it may incline below toward.

[Modification 1]
Next, a modification of the flange member in the above-described embodiment (hereinafter, this modification is referred to as “modification 1”) will be described.
FIG. 12 is an enlarged cross-sectional view of the main part of the developing device according to the first modification, cut along a cross section perpendicular to the developing roller rotation axis direction.
In the above-described embodiment, the developer splashed up by the rotational drive of the recovery chamber transport member 305 is caught in the rotation of the recovery chamber transport member 305, and the recovery chamber is indicated by reference numeral G ′ shown in FIG. In some cases, the conveying member 305 and the collar member 330 may move. This movement may cause the developer to reach the lower case gap CG and hinder the momentum of the airflow flowing through the lower case gap CG.

  Therefore, as shown in FIG. 12, the flange member 340 in the first modification includes a convex portion 340a on the lower surface thereof. The eaves member 340 according to the first modification has a shape that is bent downward in an L shape along the long side of the plate-like member that is long in the direction of the rotation axis of the developing roller, and the bent portion is a convex portion 340a. It has become. The convex portion 340a does not necessarily have to be formed in the longitudinal direction of the flange member 340, and a part of the longitudinal direction (particularly, a location where it is desired to inhibit the movement of the developer between the recovery chamber transport member 305 and the flange member 330) ) May be provided only on the convex portion. Further, the shape of the convex portion 340a is not limited to that formed by bending a plate-like member as in the first modification, and a member that becomes the convex portion 340a is attached to the plate-like saddle member main body. It may be a configuration or the like. What is the shape of the convex portion 240a as long as it can hinder the movement of the developer between the collection chamber conveying member 305 and the collar member 330 as compared to the case where at least the convex portion 240a does not exist? It may be.

  In the first modification, the developer that is about to move between the collection chamber transport member 305 and the collar member 330 is guided downward by the convex portion 340a as indicated by reference numeral G in FIG. As a result, the recovery chamber conveyance member 305 is rotated toward the side away from the developing roller 302 as the recovery chamber conveyance member 305 rotates.

[Modification 2]
Next, another modified example (hereinafter, this modified example is referred to as “modified example 2”) in the above-described embodiment will be described.
FIG. 14 is an enlarged cross-sectional view of the main part of the developing device according to Modification 2 taken along a cross section perpendicular to the developing roller rotation axis direction.
In the second modification, the magnetic plate 350 is provided so as to face the developing roller surface portion between the peeling region γ and the developer storage space ε in the developing roller surface moving direction. The magnetic plate 350 is attached to the partition plate 306 of the developing case 301. By providing this magnetic plate 350, the role of a magnetic seal is fulfilled. That is, when the magnetic plate 350 functions as a magnetic seal, the magnetic field generated by the magnet MG5 of the magnet roller 302d for pumping up the developer in the developer storage space ε onto the developing roller near the separation region γ. Suppresses acting on the remaining developer. Thereby, it is possible to suppress the developer remaining on the developing roller 302 from being conveyed to the developer storage space ε.

[Modification 3]
Next, still another modified example (hereinafter referred to as “modified example 3”) in the above-described embodiment will be described.
FIG. 17 is an enlarged cross-sectional view of the main part of the developing device according to the third modification when cut along a cross section perpendicular to the developing roller rotation axis direction.
FIG. 18 is an enlarged cross-sectional view of the vicinity of the flange member of the developing device according to the third modification.

  In the third modification, the developing roller surface movement direction downstream side of the developing roller surface portion where the one end portion of the flange member 330 is opposed to the position where the developer 320 is supplied (developer storage space ε). A guide auxiliary roller 360 as a rotating body is disposed opposite to the developing roller surface portion upstream of the developing roller surface movement direction. Specifically, it is attached to a partition plate 306 that partitions the supply chamber 304a and the recovery chamber a.

  The auxiliary guide roller 360 is rotationally driven by a roller driving unit 361 as a rotational driving means so that the surface of the guide auxiliary roller 360 moves in the direction opposite to the direction of movement of the developing roller at a position where the auxiliary guiding roller 360 and the surface of the developing roller are opposed. . The gap (gap) G1 between the guide auxiliary roller 360 and the developing roller surface is set to be narrower than the gap (gap) G2 between one end of the collar member 330 and the developing roller surface.

  The developer 320 that is peeled off in the peeling region γ by the repulsive magnetic field generated by the peeling magnetic poles generated by the magnets MG3 and MG4 is received by the upper surface of the flange member 330 and moves on the upper surface of the flange member 330 to move the other end of the flange member 330. To the recovery chamber 305a from the gap between the other end of the collar member 330 and the inner wall of the developing case. At this time, if the developer does not move smoothly on the upper surface of the collar member 330 and a traffic jam occurs, the separation of the developer in the separation region γ is inhibited, or the gap between one end of the collar member 330 and the developing roller surface. This causes a problem that the developer falls from the gap G2 and the amount of developer falling near the lower case gap CG increases. In particular, in a high-temperature and high-humidity environment, the developer fluidity is lowered, so that the developer is likely to be jammed on the upper surface of the flange member 330, and such a problem is likely to occur.

  In the third modification, by rotating the guide auxiliary roller 360 described above, the developer that has passed through the gap G2 between the flange member 330 and the developing roller surface is moved in the surface movement direction of the guide auxiliary roller 360. Can give power. Thereby, the movement of the developer from one end side to the other end side of the collar member 330 on the upper surface of the collar member 330 can be promoted, and the congestion of the developer on the upper surface of the collar member 330 can be suppressed. it can. As a result, the occurrence of the above-described problems can be suppressed.

  In particular, in the third modification, the guide auxiliary roller is configured such that the gap (gap) G3 between the guide auxiliary roller 360 and the flange member 330 is wider than the gap G1 between the guide auxiliary roller 360 and the developing roller surface. 360 is arranged. Accordingly, the developer can be smoothly fed to the upper surface of the collar member 330 by the rotation of the auxiliary guide roller 360, and the movement of the developer from one end side to the other end side of the collar member 330 can be efficiently promoted. it can.

  Moreover, in this modification 3, the surface of the guidance assistance roller 360 is comprised with the magnetic member. Thereby, like the magnetic plate 350 of the modified example 2, it can serve as a magnetic seal. In addition, the developer on the developing roller that has passed through the peeling region γ can be blocked by the gap by the action of a magnetic field formed in the gap G1 between the auxiliary guide roller 360 and the developing roller. Thereby, it is possible to assist the separation of the developer from the surface of the developing roller. Further, the movement of the developer by the rotation of the guide auxiliary roller 360 is also smooth.

  In the third modification, the gap G1 between the auxiliary guide roller 360 and the developing roller is preferably 0.7 mm or greater and 1.0 mm or less. When the gap G1 is less than 0.7 mm, it is easy to fix the developer on the developing roller by pressing the developer that rotates around the developing roller 302 without being separated in the peeling region γ on the surface of the guide auxiliary roller 360. Because. On the other hand, when the gap G1 exceeds 1.0 mm, the developer that cannot be peeled off in the peeling region γ and is rotated around the developing roller 302 passes through the guide without being supplemented by the magnetic field formed in the gap G1. This is because the effect of guiding the developer to the upper surface of the collar member 330 is limited by the rotation of the auxiliary roller 360.

  In the third modification, the gap G3 between the auxiliary guide roller 360 and the eaves member 330 is preferably 2 mm or more and 3 mm or less. If the gap G3 is less than 2 mm, the movement of the developer due to the rotation of the auxiliary guide roller 360 is hindered by the gap G3, and the developer G is likely to be jammed in the gap G3. On the other hand, when the gap G3 exceeds 3 mm, the rotation of the auxiliary guide roller 360 is less likely to act on the developer on the upper surface of the collar member 330, and the developer on the upper surface of the collar member 330 is moved to the other end of the collar member 330. It is because the effect to make becomes limited.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
Includes magnetic field generating means such as a magnet roller 302d having a plurality of magnetic poles including two peeling magnetic poles (magnetic poles by magnets MG3 and MG4) that are adjacent to each other in the moving direction of the developer carrying member and have the same polarity. And a developer carrying member such as a developing roller 302 that conveys the developer to a developing region facing the surface of the latent image carrying member such as the photosensitive member 1 by carrying the developer comprising the magnetic carrier on the surface and moving the surface. And a developer supply in a supply chamber 304a or the like for conveying the developer supplied on the surface of the developer carrier along the rotation direction of the developer carrier by a developer supply and conveyance member such as a supply chamber conveyance member 304. The developer separated from the surface of the developer carrier by the two magnetic poles at a position below the transport path and the developer supply transport path is recovered, and the developer circulation such as the recovery chamber transport member 305 is recovered. In a developing device 3 having a developer recovery transport path such as a recovery chamber 305a that is transported along a developer carrier rotation axis direction by a transport member, and a developing case 301 formed therein, in the developer carrier surface movement direction. One end side of the two magnetic poles is opposed to the developer carrying member surface portion between the portions P3 and P4 where the normal direction magnetic flux density on the developer carrying member surface is maximum, with a predetermined interval, and A developer guide member such as a collar member 330, the other end side of which is opposite to the one end side facing the inner wall of the developing case constituting the developer collecting and conveying path with a predetermined interval, Is arranged at a position for receiving at least a part of the developer that is detached from the surface of the developer carrying member.
According to this, at least a part of the developer peeled off from the developer carrying member is received by the upper surface of the developer guide member, and thereafter, the upper surface of the developer guide member is guided to the interval on the other end side. Then, the developer falls into the developer collection conveyance path and is collected. Thereby, it is possible to reduce the amount of the developer that has peeled off from the developer carrying member and falls near the gap (lower case gap) CG between the surface of the developer carrying member and the developing case. As a result, it is possible to suppress a situation where the momentum of the airflow flowing through the gap (lower case gap) CG is hindered by the developer peeled from the developer carrier and the toner scattering suppression effect is reduced.

(Aspect B)
In the aspect A, the developer collecting and conveying member is constituted by a screw member provided with a spiral fin on a rotating shaft, and when the developer in the developer collecting and conveying path is conveyed, The fin is configured so that a conveying force in a direction away from the developer carrying member is applied to the developer existing at the bottom in the developer collecting conveyance path.
According to this, the developer in the developer recovery transport path is transported in the direction of the rotation axis of the developer recovery transport member in a state of being brought closer to the side away from the developer carrier. As a result, the developer in the developer recovery transport path can be moved away from the lower case gap CG, so that the internal space of the developer recovery transport path adjacent to the lower case gap CG (a space through which airflow can pass) Can be secured widely. As a result, the loss of the momentum of the airflow flowing from the lower case gap CG into the developer recovery conveyance path can be reduced, and a strong airflow can be generated by the lower case gap CG.

(Aspect C)
In the aspect B, the horizontal position of the other end portion of the developer guide member is located on a side farther from the developer carrier than the rotation shaft of the screw member.
In the aspect B, the developer is flipped up by the rotational drive of the developer collecting and conveying member at a position farther from the developer carrying member than the rotation shaft of the screw member. Therefore, the developer splashed up in this way may move to the lower case gap CG via the upper space of the developer collection conveyance path, and may hinder the momentum of the airflow flowing through the lower case gap CG. According to this aspect, the position at which the developer on the developer guide member falls into the developer collection / conveyance path is a position on the side farther from the developer carrying member than the rotation shaft of the screw member. As a result, the developer falling from the developer guide member can collide with the developer splashed up by the rotational drive of the developer collecting and conveying member, and the kinetic energy can be consumed. As a result, it is possible to reduce the amount of developer that jumps up by the rotational drive of the developer collecting and conveying member and reaches the lower case gap CG, and hinders the momentum of the airflow flowing through the lower case gap CG. Can be suppressed.

(Aspect D)
In the aspect B or C, the developer guide member has a convex portion on at least a part of a lower surface thereof.
According to this, the flow of the developer moving between the developer collecting and conveying member and the developer guide member by the rotational driving of the developer collecting and conveying member can be inhibited by the convex portion. As a result, the amount of developer that moves between the developer collecting and conveying member and the developer guide member and reaches the lower case gap CG can be reduced, and the momentum of the airflow flowing through the lower case gap CG is hindered. Can be suppressed.

(Aspect E)
In any one of the aspects A to D, the developer supply member surface movement direction downstream from the point on the developer carrier surface on which the one end side of the developer guide member is opposed, and the developer supply A distance G2 between the one end side of the developer guide member and the surface of the developer carrier, upstream of the developer carrier surface movement direction from a point on the surface of the developer carrier to which the developer from the conveyance path is supplied. A rotating member such as a guide auxiliary roller 360 disposed opposite to the surface of the developer carrying member with a narrower gap G1 and the surface of the rotating member facing the developer carrying member surface. Rotation driving means such as a roller driving unit 361 for driving the rotating body so as to move in the direction opposite to the body surface moving direction.
According to this, the movement of the developer on the upper surface of the developer guide member to the other end side of the developer guide member can be promoted by the rotation of the rotating body. As a result, the developer is congested on the upper surface of the developer guide member, and the peeling of the developer from the surface of the developer carrier is inhibited, or between the one end side of the developer guide member and the surface of the developer carrier. When the developer falls from the gap G2, the amount of developer falling near the gap (lower case gap) CG between the surface of the developer carrying member and the developing case increases, and the toner scattering suppression effect decreases. Can be suppressed.

(Aspect F)
In the aspect E, the rotating body is arranged such that a gap G3 with the developer guide member is larger than a gap G1 with the surface of the developer carrying member.
According to this, the developer can easily move through the gap G3 between the rotating body and the developer guide member by the rotation of the rotating body, and the developer on the upper surface of the developer guide member can be more smoothly transferred to the other end of the developer guide member. Can be moved to the side.

(Aspect G)
In the aspect E or F, the rotating body is attached to a wall (partition plate 306) of a developing case that divides the developer supply transport path and the developer recovery transport path.
According to this, attachment of a rotary body becomes easy.

(Aspect H)
In any one of the above aspects E to G, the surface of the rotating body is formed of a magnetic member.
According to this, the developer on the developer carrier that has passed through the peeling region can be dammed up at the interval G1 by the action of the magnetic field formed at the interval G1 between the rotating body and the developer carrier. Thereby, it is possible to assist the separation of the developer from the surface of the developer carrying member. Further, the developer moves smoothly by the rotation of the rotating body.

(Aspect I)
At least a latent image carrier such as the photosensitive member 1, a charging means such as a charging device 2 for charging the surface of the latent image carrier, and an exposure device for forming an electrostatic latent image on the latent image carrier. In an image forming apparatus such as a printer 100 having a latent image forming unit such as 16 and a developing unit such as the developing device 3 for developing the electrostatic latent image into a toner image, the above-described aspect is used as the developing unit. A developing device according to any one of A to H is used.
According to this, since the momentum of the airflow flowing through the lower case gap CG of the developing device is hindered by the developer peeled from the developer carrier, it is possible to suppress the situation where the toner scattering suppression effect is reduced. Fewer image forming apparatuses can be realized.

(Aspect J)
At least the latent image in an image forming apparatus such as a printer 100 including a latent image carrier such as the photosensitive member 1 that carries the latent image and a developing unit such as a developing device 3 that develops the latent image on the latent image carrier. In the process cartridge in which the carrier and the developing unit are held by a common holding body as a unit and are detachable from the main body of the image forming apparatus, the developing unit according to any one of the aspects A to H A developing device is used.
According to this, since the momentum of the airflow flowing through the lower case gap CG of the developing device is hindered by the developer peeled from the developer carrier, it is possible to suppress the situation where the toner scattering suppression effect is reduced. A small number of process cartridges can be realized.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Developing device 15 Transfer conveying belt 16 Exposure device 17 Image forming device 24 Fixing device 100 Printer 301 Developing case 301b Protruding portion 302 Developing roller 302c Developing sleeve 302d Magnet roller 303 Developer regulating member 304 Supply chamber conveying member 304a Supply chamber 305 Recovery chamber transport member 305a Recovery chamber 306 Partition plate 309 Toner supply port 320 Developer 330, 340 Edge member 350 Magnetic plate 360 Guide auxiliary roller 361 Roller drive part CG Lower case gap GP Development gaps MG1 to MG5 Magnet P Recording paper α Development area γ Peeling area ε Developer storage space

JP 2013-33223 A

Claims (10)

A developer carrier surface including a magnetic field generating means having a plurality of magnetic poles including two magnetic poles adjacent to each other and having the same polarity in the moving direction of the surface of the developer carrier, and carrying a developer comprising toner and a magnetic carrier on the surface A developer carrier that transports the developer to a development region that faces the surface of the latent image carrier by moving;
A developer supply conveyance path for conveying the developer supplied on the surface of the developer carrier along the rotation direction of the developer carrier by the developer supply conveyance member, and below the developer supply conveyance path At the position, a developer recovery transport path is provided for recovering the developer separated from the surface of the developer support by the two magnetic poles and transporting the developer along the direction of the axis of the developer support by the developer recovery transport member. In a developing device having a formed developing case,
One end of the two magnetic poles in the direction of movement of the developer carrier surface is spaced a predetermined distance from the surface of the developer carrier between portions where the normal magnetic flux density on the developer carrier surface is maximum. And the other end side opposite to the one end side is provided with a developer guide member facing the inner wall of the developer case constituting the developer recovery transport path with a predetermined interval,
The developing device, wherein the developer guide member is disposed at a position where the upper surface receives at least a part of the developer separated from the surface of the developer carrying member. The developing device according to claim 1.
The developer collecting / conveying member is constituted by a screw member provided with a helical fin on a rotating shaft, and the developer is conveyed by the fin of the screw member when conveying the developer in the developer collecting / conveying path. A developing device configured to apply a conveying force in a direction away from a developer carrier to a developer present at a bottom portion in a recovery conveyance path. The developing device according to claim 2.
The developing device according to claim 1, wherein a horizontal position of the other end portion of the developer guide member is located on a side farther from the developer carrier than a rotation shaft of the screw member. The developing device according to claim 2 or 3,
The developing device according to claim 1, wherein the developer guide member has a convex portion on at least a part of a lower surface thereof. The developing device according to any one of claims 1 to 4,
A developer to which the developer is supplied from the developer supply conveyance path, which is downstream of the developer carrier surface movement direction from a point on the developer carrier surface facing the one end side of the developer guide member. On the upstream side of the developer carrier surface moving direction from the point on the surface of the carrier, the developer guide member surface is spaced from the one end side of the developer guide member by a distance narrower than the distance between the developer carrier surface. A rotating body arranged oppositely,
Rotation driving means for driving the rotating body so that the surface of the rotating body moves in a direction opposite to the moving direction of the developer carrying body at a position facing the surface of the developer carrying body. Developing device. The developing device according to claim 5.
The developing device according to claim 1, wherein the rotating body is disposed so that a distance between the rotating body and the developer guide member is larger than a distance between the rotating body and the surface of the developer carrier. The developing device according to claim 5 or 6,
The developing device, wherein the rotating body is attached to a wall portion of a developing case that divides the developer supply transport path and the developer recovery transport path. The developing device according to any one of claims 5 to 7,
The developing device according to claim 1, wherein the surface of the rotating body is made of a magnetic member. At least a latent image carrier, a charging unit for charging the surface of the latent image carrier, a latent image forming unit for forming an electrostatic latent image on the latent image carrier, and the electrostatic latent image In an image forming apparatus having a developing means for developing and forming a toner image,
An image forming apparatus using the developing device according to claim 1 as the developing unit. In an image forming apparatus comprising a latent image carrier that carries a latent image and a developing unit that develops the latent image on the latent image carrier, at least the latent image carrier and the developing unit are shared as one unit. In the process cartridge that is held by the holding body and is detachable from the image forming apparatus main body,
9. A process cartridge using the developing device according to claim 1 as the developing means.