JP2012155144A - Developing device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact developing device in which an excessive portion of a developer is stably discharged from a developer container by employing a simple structure, and an image forming apparatus including the same.SOLUTION: A developing device 2 comprises: a conveyance blade 51 provided between a second stirring member 44 and a developer discharge port 22h so as to oppose a downstream communicating part 22f for conveying a developer from a second conveyance path 22d to a first conveyance path 22c through the downstream communicating part 22f; and a plurality of regulating plates 52 disposed between the conveyance blade 51 and the developer discharge port 22h for regulating movement of the developer from the conveyance blade 51 toward the developer discharge port 22h. The regulating plates 52 are provided in a plural number so as to oppose a downstream wall part 22j at intervals along a direction of a rotational axis 44b.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic system, and an image forming apparatus including the developing device. The present invention relates to a developing device that replenishes developer and discharges excess developer, and an image forming apparatus including the developing device.

  In an image forming apparatus, a latent image formed on an image carrier made of a photoreceptor or the like is developed by a developing device and visualized as a toner image. As one of such developing devices, a two-component developing system using a two-component developer is employed. In this type of developing device, a developer composed of a carrier and toner is accommodated in a developer container, a developing roller for supplying the developer to the image carrier is disposed, and the developer in the developer container is conveyed and stirred. However, a stirring member for supplying the developing roller is provided.

  In this developing device, the toner is consumed by development, while the carrier is not consumed and remains in the developing container. Therefore, the carrier stirred together with the toner in the developing container deteriorates as the stirring frequency increases, and as a result, the charge imparting performance of the carrier with respect to the toner gradually decreases.

  In view of this, there has been proposed a developing device in which a developer containing a carrier is replenished in a developing container and a surplus developer is discharged to suppress a decrease in charging performance.

  For example, in Patent Document 1, two stirring members each having a rotation shaft and a spiral blade formed in a spiral shape on the outer periphery thereof are arranged in parallel in each conveyance path. A partition portion is provided between the conveyance paths, and communication portions for delivering the developer are provided at both ends of the partition portion. A developer discharge port is formed on the downstream side of the conveyance path with respect to the developer conveyance direction, and a spiral shape is formed between the stirring member and the developer discharge port in a direction opposite to the spiral blade of the stirring member. The reverse spiral blade is integrally provided on the rotating shaft. In this configuration, when the developer is supplied into the developing container, the developer is conveyed to the downstream side of the conveyance path while being agitated by the rotation of the agitating member. When the reverse spiral blade rotates in the same direction as the stirring member, the reverse spiral blade imparts a transport force in the direction opposite to the developer transport direction by the stirring member to the developer. Due to this reverse conveyance force, the developer is blocked and bulky on the downstream side of the conveyance path, so that excess developer moves over the reverse spiral blade to the developer discharge port and is discharged to the outside. The

  However, in the above-described prior art, the reverse spiral blade is provided between the downstream side of the conveyance path and the developer discharge port, and is formed in a spiral shape, which increases the size of the apparatus in the axial direction. Further, the developer is blocked by the reverse spiral blade, and the bulky developer moves to the developer discharge port side. However, depending on the direction (phase) of the reverse spiral blade, In addition, since the bulk of the developer is different, there is a disadvantage that the developer cannot be discharged stably.

JP 2001-265098 A (paragraphs [0021], [0023], [0024], [0028], FIG. 4)

  The present invention has been made to solve the above-described problems, and is a small-sized developing device that stably discharges excess developer from a developing container with a simple configuration, and an image forming apparatus including the developing device. The purpose is to provide.

  In order to achieve the above object, a first invention is a developing device that agitates and conveys a developer and supplies the agitated developer to a developing roller, and has a spiral shape that extends in the axial direction around a rotation axis. A plurality of stirring members that have blades and stir and transport the developer supplied to the developing roller; a partition portion that divides a transport path in which the developer is circulated and transported by each of the stirring members; and the partition portion and the longitudinal direction Any one of the communication path formed by the side wall portions provided on both end sides of the sheet, the communication section for communicating the respective conveyance paths, the developer supply port for supplying the developer to the conveyance path, and the conveyance path. And a developer discharge port for discharging excess developer, and the stirring member disposed in the one transport path includes the spiral blade and the developer. Communication with the agent outlet A conveying blade that conveys the developer from the one conveying path to the other conveying path via the communicating portion, and is provided between the conveying blade and the developer discharge port, A regulating plate that regulates the movement of the developer from the conveying blade to the developer discharge port side, and a plurality of the regulating plates are arranged opposite to the side wall portion and spaced apart in the direction of the rotation axis. It is characterized by.

  According to a second aspect of the present invention, in the above developing device, the restriction plate is provided at least at a position facing the end surface of the side wall portion on the side of the communicating portion and a position closest to the developer discharge port. It is a feature.

  According to a third aspect of the present invention, in the above developing device, the plurality of restriction plates include three restriction plates having the same outer diameter.

  According to a fourth aspect of the present invention, in the above developing device, the regulating plate is provided so that the outer diameter increases in order from the position facing the end surface of the side wall portion on the communicating portion side toward the developer discharge port. It is characterized by being able to.

  According to a fifth aspect of the invention, there is provided an image forming apparatus including the developing device having the above-described configuration.

  According to the first invention, the developer is supplied into the conveyance path from the developer supply port. The developer replenished in the transport path is transported while being stirred by the stirring member, and is transported to the downstream side of one transport path. On the downstream side, the developer is blocked by a plurality of restriction plates, and is conveyed from the communicating portion to the other conveyance path side by the rotation of the conveyance blades without being conveyed to the developer discharge port. However, the developer that is bulkier than the regulating plate is conveyed to the gap between the outer peripheral surface of the regulating plate and the side wall, and overflows from the gap to the developer discharge port as an excess developer. Therefore, the apparatus can be reduced in size with a simple configuration of providing a plurality of regulating plates, and the excess developer can be stably discharged out of the developing device from the developer discharge port.

1 is a diagram illustrating an image forming apparatus including a developing device according to a first embodiment of the present invention. Sectional drawing which shows schematically the developing device which concerns on 1st Embodiment Sectional top view which shows the stirring part of the developing device which concerns on 1st Embodiment. Plan sectional drawing which shows the developer discharge part of the developing device concerning a 1st embodiment. Plan sectional drawing which shows the developer discharge part which concerns on 2nd Embodiment. Plan sectional drawing which shows the developer discharge part which concerns on 3rd Embodiment. Plan sectional drawing which shows the developer discharge part which concerns on Example 4 of this invention. Plan sectional drawing which shows the developer discharge part concerning a comparative example The figure which shows the change of the developer discharge amount of the developer discharge part which concerns on the Example and comparative example of this invention

  Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Further, the use of the invention and the terms shown here are not limited thereto.

(First embodiment)
FIG. 1 is a diagram showing a configuration of an image forming apparatus equipped with a developing device according to an embodiment of the present invention. The image forming apparatus 1 is a tandem type color printer, and the rotatable photoconductors 11a to 11d use an organic photoconductor (OPC photoconductor) as a photosensitive material for forming a photosensitive layer, and are black, yellow, cyan. , And magenta. Around each of the photoreceptors 11a to 11d, developing devices 2a to 2d, an exposure unit 12, chargers 13a to 13d, and cleaning devices 14a to 14d are disposed.

  The developing devices 2a to 2d are arranged to face the right sides of the photoconductors 11a to 11d, respectively, and supply toner to the photoconductors 11a to 11d. The chargers 13a to 13d are arranged on the upstream side of the developing devices 2a to 2d with respect to the rotation direction of the photosensitive member and opposed to the surfaces of the photosensitive members 11a to 11d, and uniformly charge the surfaces of the photosensitive members 11a to 11d. .

  The exposure unit 12 scans and exposes each of the photoconductors 11a to 11d based on image data such as characters and pictures input to an image input unit (not shown) from a personal computer or the like. The developing device 2a ~ 2d below. The exposure unit 12 is provided with a laser light source and a polygon mirror, and a reflection mirror and a lens are provided corresponding to each of the photoconductors 11a to 11d. Laser light emitted from the laser light source is applied to the surfaces of the photoconductors 11a to 11d from the downstream side of the chargers 13a to 13d in the rotation direction of the photoconductors via the polygon mirror, the reflection mirror, and the lens. Electrostatic latent images are formed on the surfaces of the photoconductors 11a to 11d by the irradiated laser light, and the electrostatic latent images are developed into toner images by the developing devices 2a to 2d.

  The endless intermediate transfer belt 17 is stretched around the tension roller 6, the driving roller 25, and the driven roller 27. The driving roller 25 is rotationally driven by a motor (not shown), and the intermediate transfer belt 17 is circulated and driven by the rotation of the driving roller 25.

  The photoreceptors 11a to 11d are arranged below the intermediate transfer belt 17 so as to be in contact with the intermediate transfer belt 17 along the rotation direction (arrow direction in FIG. 1). The primary transfer rollers 26a to 26d face the photoconductors 11a to 11d with the intermediate transfer belt 17 interposed therebetween, and press contact with the intermediate transfer belt 17 to form a primary transfer portion. In the primary transfer portion, the toner images on the photoconductors 11a to 11d are sequentially transferred to the intermediate transfer belt 17 at a predetermined timing as the intermediate transfer belt 17 rotates. As a result, a toner image is formed on the surface of the intermediate transfer belt 17 by superimposing four color toner images of magenta, cyan, yellow, and black.

  The secondary transfer roller 34 faces the driving roller 25 with the intermediate transfer belt 17 interposed therebetween, and presses against the intermediate transfer belt 17 to form a secondary transfer portion. In this secondary transfer portion, the toner image on the surface of the intermediate transfer belt 17 is transferred to the paper P. After the transfer, the belt cleaning device 31 cleans the toner remaining on the intermediate transfer belt 17.

  A paper feed cassette 32 that stores paper P is disposed below the image forming apparatus 1, and a stack tray 35 that supplies manually fed paper is disposed to the right of the paper feed cassette 32. On the left side of the paper feed cassette 32, a first paper transport path 33 for transporting the paper P fed from the paper feed cassette 32 to the secondary transfer portion of the intermediate transfer belt 17 is disposed. Further, on the left side of the stack tray 35, a second paper transport path 36 for transporting paper fed from the stack tray 35 to the secondary transfer unit is disposed. Further, on the upper left side of the image forming apparatus 1, a fixing unit 18 that performs a fixing process on the sheet P on which an image is formed, and a third sheet transport that transports the sheet on which the fixing process has been performed to the sheet discharge unit 37. A path 39 is provided.

  The paper feed cassette 32 can be replenished by pulling it out of the apparatus (the front side of the paper surface in FIG. 1). The paper P stored therein is first fed one by one by the pickup roller 33b and the separating roller 33a. The paper is fed out to the paper conveyance path 33 side.

  The first paper transport path 33 and the second paper transport path 36 merge before the registration roller 33c, and the registration roller 33c takes the timing of the image forming operation and the paper feeding operation in the intermediate transfer belt 17, The paper P is conveyed to the secondary transfer unit. The sheet P conveyed to the secondary transfer unit is secondarily transferred with the toner image on the intermediate transfer belt 17 by the secondary transfer roller 34 to which a bias potential is applied, and is conveyed to the fixing unit 18.

  The fixing unit 18 includes a fixing belt heated by a heater, a fixing roller inscribed in the fixing belt, a pressure roller disposed in pressure contact with the fixing roller with the fixing belt interposed therebetween, and the toner image is transferred. The fixing process is performed by heating and pressurizing the sheet P. After the toner image is fixed by the fixing unit 18 on the paper P, the toner image is reversed by the fourth paper conveyance path 40 as necessary, and the toner image is secondarily transferred to the back surface of the paper by the secondary transfer roller 34 to be fixed. Fixing is performed at the portion 18. The sheet on which the toner image is fixed passes through the third sheet conveyance path 39 and is discharged to the sheet discharge unit 37 by the discharge roller 19a.

  FIG. 2 is a cross-sectional view showing a configuration of a developing device used in the image forming apparatus 1 described above. In the following description, the configuration and operation of the developing device 2a corresponding to the photoconductor 11a shown in FIG. 1 will be described. However, the configuration and operation of the developing devices 2b to 2d are the same as those of the developing device 2a. Omitted, and reference numerals a to d indicating developing devices and photoconductors of the respective colors are omitted.

  The developing device 2 includes a developing roller 20, a magnetic roller 21, a regulating blade 24, a stirring member 42, a developing container 22, and the like.

  The developing container 22 constitutes the outline of the developing device 2, and is partitioned into a first transport path 22c and a second transport path 22d by a partition portion 22b at a lower portion thereof. The first transport path 22c and the second transport path 22d contain a developer composed of a carrier and toner. Further, the developing container 22 rotatably holds the stirring member 42, the magnetic roller 21, and the developing roller 20. Further, the developing container 22 is formed with an opening 22 a that exposes the developing roller 20 toward the photoconductor 11.

  The developing roller 20 faces the photoreceptor 11 and is disposed on the right side of the photoreceptor 11 with a certain interval. Further, the developing roller 20 forms a developing region D for supplying toner to the photoconductor 11 at a facing position close to the photoconductor 11. The magnetic roller 21 is opposed to the developing roller 20 with a certain interval, and is disposed on the lower right side of the developing roller 20. Further, the magnetic roller 21 supplies toner to the developing roller 20 at a facing position close to the developing roller 20. The regulating blade 24 is fixedly held on the developing container 22 obliquely to the left of the magnetic roller 21. The stirring member 42 is disposed substantially below the magnetic roller 21.

  The stirring member 42 includes two members, a first stirring member 43 and a second stirring member 44. The second stirring member 44 is provided in the second transport path 22d below the magnetic roller 21, and the first stirring member 43 is provided in the first transport path 22c adjacent to the right side of the second stirring member 44. It is done.

  The first and second stirring members 43 and 44 stir the developer to charge the toner in the developer to a predetermined level. As a result, the toner is held on the carrier. In addition, communication portions (not shown) are provided on both ends in the longitudinal direction (the front and back direction in FIG. 2) of the partition 22b that partitions the first transport path 22c and the second transport path 22d. When the stirring member 43 rotates, the charged developer is transported into the second transport path 22d from one communicating portion provided in the partition portion 22b, and circulates in the first transport path 22c and the second transport path 22d. To do. Then, the developer is supplied from the second stirring member 44 to the magnetic roller 21.

  The magnetic roller 21 includes a roller shaft 21a, a magnetic pole member M, and a rotating sleeve 21b made of a nonmagnetic material. The magnetic roller 21 carries the developer supplied by the second agitating member 44, and only the toner from the carried developer is developed by the developing roller 20. To supply. The magnetic pole member M is composed of a plurality of magnets with different polarities at the outer peripheral portion formed in a sector shape, and is fixed to the roller shaft 21a by adhesion or the like. The roller shaft 21a is supported by the developing container 22 in a non-rotatable manner with a predetermined interval between the magnetic pole member M and the rotating sleeve 21b in the rotating sleeve 21b. The rotating sleeve 21b is rotated in the same direction as the developing roller 20 (clockwise direction in FIG. 2) by a driving mechanism including a motor and a gear (not shown), and a bias 56 in which the AC voltage 56b is superimposed on the DC voltage 56a is applied. The On the surface of the rotating sleeve 21 b, the charged developer is carried by forming a magnetic brush by the magnetic force of the magnetic pole member M, and the magnetic brush is adjusted to a predetermined height by the regulating blade 24.

  When the rotating sleeve 21b rotates, the magnetic brush is carried on the surface of the rotating sleeve 21b by the magnetic pole member M and conveyed. When the magnetic brush rises at the magnetic pole member 20b provided on the developing roller 20 and contacts the developing roller 20, the magnetic brush Only the toner is supplied to the developing roller 20 in accordance with the bias 56 applied to the rotating sleeve 21b.

  The developing roller 20 includes a fixed shaft 20a, a magnetic pole member 20b, a developing sleeve 20c formed in a cylindrical shape with a nonmagnetic metal material, and the like.

  The fixed shaft 20a is supported by the developing container 22 so as not to rotate. A developing sleeve 20c is rotatably held on the fixed shaft 20a. Further, a magnetic pole member 20b made of a magnet is fixed to the developing sleeve 20c at a position facing the magnetic roller 21 by adhesion or the like. The The developing sleeve 20c is rotated in an arrow direction (clockwise direction) in FIG. 2 by a driving mechanism including a motor and a gear (not shown). A developing bias 57 in which an AC voltage 57b is superimposed on a DC voltage 57a is applied to the developing sleeve 20c.

  When the developing bias 57 is applied to the developing sleeve 20c, the toner carried on the surface of the developing sleeve 20c is directed toward the photosensitive member 11 in the developing region D due to the potential difference between the developing bias potential and the potential of the exposed portion of the photosensitive member 11. To fly. The flying toner sequentially adheres to the exposed portion on the photoconductor 11 rotating in the direction of arrow A (counterclockwise direction), and the electrostatic latent image on the photoconductor 11 is developed.

  Next, the stirring unit of the developing device will be described in detail with reference to FIG. FIG. 3 is a plan cross-sectional view of the stirring unit as viewed from above.

  As described above, the developing container 22 includes the first transport path 22c, the second transport path 22d, the partition 22b, the upstream communication section 22e, and the downstream communication section 22f. A developer supply port 22g, a developer discharge port 22h, an upstream side wall portion 22i, and a downstream side wall portion 22j are formed.

  The partition part 22b extends in the longitudinal direction of the developing container 22 and partitions the first transport path 22c and the second transport path 22d in parallel. An upstream side communication portion 22e and a downstream side communication portion 22f are provided at both ends in the longitudinal direction of the partition portion 22b. The developer is supplied to the first conveyance path 22c, the upstream communication portion 22e, and the second conveyance portion. It is possible to circulate through the passage 22d and the downstream communication portion 22f.

  The developer supply port 22g is an opening for supplying new toner and carrier into the developer container 22 from a developer supply container (not shown) provided in the upper portion of the developer container 22, and is provided in the first transport path 22c. Arranged on the upstream side (left side in FIG. 2).

  The developer discharge port 22h is an opening for discharging the developer remaining in the first and second transport paths 22c and 22d due to the replenishment of the developer. The developer discharge port 22h is located downstream of the second transport path 22d. 2 are provided continuously in the longitudinal direction of the transport path 22d.

  A first stirring member 43 is disposed in the first transport path 22c, and a second stirring member 44 is disposed in the second transport path 22d.

  The first stirring member 43 includes a rotation shaft 43b and first spiral blades 43a that are provided integrally with the rotation shaft 43b and formed in a spiral shape at a constant pitch in the axial direction of the rotation shaft 43b. Further, the first spiral blade 43a extends to both end portions in the longitudinal direction of the first transport path 22c, and is provided to face the upstream and downstream communication portions 22e and 22f. The rotating shaft 43b is rotatably supported by the upstream side wall portion 22i and the downstream side wall portion 22j of the developing container 22.

  The second stirring member 44 is provided integrally with the rotation shaft 44b and the rotation shaft 44b, and spirals with blades in the same direction as the first spiral blade 43a in the axial direction of the rotation shaft 44b and in the direction opposite to the first spiral blade 43a. And a second spiral blade 44a formed in a shape. The second spiral blade 44a has a length equal to or longer than the axial length of the magnetic roller 21, and is provided to face the upstream communication portion 22e. The rotation shaft 44b is disposed in parallel with the rotation shaft 43b, and is rotatably supported by the upstream side wall portion 22i and the downstream side wall portion 22j of the developing container 22.

  In addition to the second spiral blade 44a, the rotation shaft 44b is provided with a transport blade 51, a plurality of regulating plates 52, and a discharge blade 53.

  The transport blade 51 is adjacent to the left side (downstream in the transport direction) of the second spiral blade 44a and is disposed to face the downstream communication portion 22f. Further, the conveying blade 51 is made of 4 to 6 rectangular sheet materials, and has a plane portion extending in parallel to the axial direction of the rotation shaft 44b, and is arranged radially around the rotation shaft 44b. With this configuration, when the transport blade 51 rotates, the developer transported downstream (left side in FIG. 2) in the second transport path 22d is transported from the downstream communication portion 22f to the first transport path 22c. become. The conveying blade 51 is integrally formed with a cylindrical shaft portion made of resin or metal, and is fixed in alignment with the rotation shaft 44b on the second spiral blade 44a side. Or the conveyance blade | wing 51 is integrally formed with the rotating shaft 44b with the 2nd spiral blade 44a.

  The plurality of regulating plates 52 block the developer conveyed downstream in the second conveyance path 22d, and convey the developer that has reached a predetermined amount or more in the conveyance blade 51 to the developer discharge port 22h. It makes it possible. The plurality of regulating plates 52 are formed of circular plates having the same diameter or less with respect to the outer periphery of the conveying blade 51 and a relatively small thickness, and are provided between the conveying blade 51 and the developer discharge port 22h. The plurality of regulating plates 52 are formed integrally with the conveying blades 51 with resin or metal.

  The rotating shaft 44b extends into the developer discharge port 22h. A discharge blade 53 is provided on the rotating shaft 44b in the developer discharge port 22h. The discharge blade 53 is formed of a spiral blade in the same direction as the second spiral blade 44a, but has a smaller pitch than the second spiral blade 44a and a smaller outer diameter of the blade. Therefore, when the rotating shaft 44b rotates, the discharge blade 53 also rotates, and the excess developer that has passed over the plurality of regulating plates 52 and is conveyed into the developer discharge port 22h is sent to the left side of FIG. 22 is discharged to the outside.

  Gears 61 to 64 are disposed on the outer walls of the upstream side wall portion 22i and the downstream side wall portion 22j. The gears 61 and 62 are fixed to the rotating shaft 43b, the gear 64 is fixed to the rotating shaft 44b, and the gear 63 is rotatably held by the upstream side wall portion 22i and meshes with the gears 62 and 64.

  Accordingly, when the gear 61 is rotated by a drive source such as a motor, the first spiral blade 43a rotates together with the rotation shaft 43b, and the first spiral blade 43a transports the developer in the first transport path 22c in the direction of arrow P. . Further, when the second spiral blade 44a rotates together with the rotating shaft 44b by the gear train of the gears 62 to 64, the second spiral blade 44a transports the developer in the second transport path 22d in the direction of arrow Q. The first conveying path 22c is agitated while circulating from the upstream communication part 22e, the second conveying path 22d, and the downstream communication part 22f. Then, the stirred developer is supplied to the magnetic roller 21.

  Next, a case where developer is supplied from the developer supply port 22g will be described. When the toner is consumed by the development, the carrier or the developer containing the carrier is supplied from the developer supply port 22g into the first conveyance path 22c at a predetermined timing.

  The replenished developer is agitated while being circulated from the first conveyance path 22c to the upstream communication section 22e, the second conveyance path 22d, and the downstream communication section 22f from the first conveyance path 22c, as in the development. The excess developer passes over the plurality of regulating plates 52 and is discharged out of the developer container 22 through the developer discharge port 22h.

  Excess developer discharge will be described in detail with reference to FIG. FIG. 4 is a plan sectional view showing the developer discharge portion.

  As shown in FIG. 4, the downstream end side of the second transport path 22d is surrounded by a downstream side wall portion 22j and a front wall portion 22k that protrude toward the downstream communication portion 22f, and from the transport blade 51 to the developer discharge port. A regulation space K that extends between 22h is formed. The restriction space K is formed in a substantially cylindrical shape, and a plurality of restriction plates 52 are disposed in the restriction space K. The end surface 22j1 of the downstream side wall portion 22j forms a downstream side communication portion 22f together with the end surface of the partition portion 22b.

  The developer discharge port 22h has a discharge port space for storing the discharge blade 53, and this discharge port space is formed in a cylindrical shape. The inner diameter of the discharge port space is smaller than the inner diameter of the restriction space K and smaller than the outer periphery of the restriction plate 52.

  The plurality of restricting plates 52 include three restricting plates 52a to 52c having the same outer diameter. The restricting plate 52a is disposed in contact with the conveying blade 51 in the axial direction at a position facing the end surface 22j1 of the downstream side wall portion 22j. The restricting plate 52c is disposed in contact with the discharge blade 53 in the axial direction at a position closest to the developer discharge port 22h. Further, the restricting plate 52b is disposed at an intermediate position in the axial direction of the restricting plates 52a and 52b.

  A gap S is formed between the outer peripheral surfaces of the plurality of regulating plates 52a to 52c and the regulating space K. Since the restricting plate 52a is located at a position facing the end surface 22j1 of the downstream side wall portion 22j, the gap S is formed over the entire circumference of the restricting plates 52a to 52c and has the same size. The excess developer conveyed to the conveyance blade 51 in the second conveyance path 22d overflows from the gap S to the developer discharge port 22h. By constituting the plurality of restriction plates 52, even if the rotational speed of the second stirring member 44 changes and the amount of developer conveyed to the plurality of restriction plates 52a to 52c varies, the plurality of restriction plates 52 In order to suppress fluctuations in the developer amount sent to the developer discharge port 22h between 52a to 52c, the discharge amount of the developer to the developer discharge port 22h can be stabilized.

(Second Embodiment)
FIG. 5 is a plan sectional view showing the developer discharge portion according to the second embodiment. The second embodiment is different from the first embodiment in that the number of restriction plates is two. The restriction plate different from the first embodiment will be mainly described, and the description of the same part as that of the first embodiment will be omitted hereinafter.

  The plurality of restricting plates 52 includes two restricting plates 52a and 52b having the same outer diameter. The restricting plate 52a is disposed in contact with the conveying blade 51 in the axial direction at a position facing the end surface 22j1 of the downstream side wall portion 22j. The restricting plate 52b is disposed in contact with the discharge blade 53 in the axial direction at a position closest to the developer discharge port 22h.

  A gap S is formed between the outer peripheral surfaces of the plurality of regulating plates 52a and 52b and the regulating space K. Since the restricting plate 52a is at a position facing the end surface 22j1 of the downstream side wall portion 22j, the gap S is formed over the entire circumference of the restricting plates 52a and 52b and has the same size. The excess developer conveyed to the conveyance blade 51 in the second conveyance path 22d overflows from the gap S to the developer discharge port 22h. By constituting the plurality of restriction plates 52, even if the rotation speed of the second stirring member 44 changes and the amount of developer conveyed to the plurality of restriction plates 52a, 52b varies, the plurality of restriction plates 52 In order to suppress fluctuations in the developer amount sent to the developer discharge port 22h between 52a and 52b, the discharge amount of the developer to the developer discharge port 22h can be stabilized.

(Third embodiment)
FIG. 6 is a plan sectional view showing a developer discharge portion according to the third embodiment. The third embodiment is different from the first embodiment in that the outer diameters of the plurality of regulating plates are different.

  The plurality of restricting plates 52 include three restricting plates 52a to 52c having different outer diameters. The restricting plate 52a is disposed in contact with the conveying blade 51 in the axial direction at a position facing the end surface 22j1 of the downstream side wall portion 22j. The restricting plate 52c is disposed in contact with the discharge blade 53 in the axial direction at a position closest to the developer discharge port 22h. Further, the restricting plate 52b is disposed at an intermediate position in the axial direction of the restricting plates 52a and 52b. The restricting plates 52a to 52c have an outer diameter that increases in order from the upstream side of the conveyance path, the restricting plates 52a and 52b are formed to have a smaller outer diameter than the conveying blade 51, and the restricting plate 52c includes the conveying blade. The outer diameter of the same size as 51 is formed.

  A gap S is formed between the outer peripheral surfaces of the plurality of regulating plates 52a to 52c and the regulating space K. Since the restriction plate 52a is located at the position facing the end surface 22j1 of the downstream side wall portion 22j, the gap S is formed over the entire circumference of the plurality of restriction plates 52a to 52c and becomes smaller toward the downstream side of the conveyance path. Yes. The excess developer conveyed to the conveyance blade 51 in the second conveyance path 22d overflows from the gap S to the developer discharge port 22h. By constituting the plurality of restriction plates 52, even if the rotational speed of the second stirring member 44 changes and the amount of developer conveyed to the plurality of restriction plates 52a to 52c varies, the plurality of restriction plates 52 In order to suppress fluctuations in the developer amount sent to the developer discharge port 22h between 52a to 52c, the discharge amount of the developer to the developer discharge port 22h can be stabilized.

  According to the first to third embodiments, the developing device 2 is provided between the second stirring member 44 and the developer discharge port 22h so as to face the downstream communication portion 22f, and is connected to the second conveying path 22d through the second conveying path 22d. A transport blade 51 that transports the developer to the one transport path 22c via the downstream communication portion 22f, and a developer that is provided on the developer discharge port 22h side of the transport blade 51 and moves to the developer discharge port 22h side. A plurality of regulating plates 52 that regulate the above. A plurality of regulating plates 52 are provided facing the downstream side wall portion 22j and spaced apart in the direction of the rotation shaft 44b (longitudinal direction).

  According to this configuration, on the downstream side of the second conveyance path 22d, the developer is blocked by the plurality of restriction plates 52, and the developer that is bulkier than the plurality of restriction plates 52 is allowed to pass through the plurality of restriction plates 52. The developer is transported to a gap S between the outer peripheral surface and the downstream side wall portion 22j, and overflows from the gap S to the developer discharge port 22h as an excess developer. Therefore, the apparatus can be reduced in size with a simple configuration in which a plurality of regulating plates 52 are provided, and even if the rotation speed of the second stirring member 44 changes, excess developer is supplied to the developer discharge port 22h. It can be discharged stably. Further, it is possible to apply to the developing device 2 in which the rotation speed of the stirring member 42 can be switched between full speed and half speed, for example, and various developing devices 2 having different rotation speeds of the stirring member 42 are mounted on the image forming apparatus 1. It becomes possible to do.

  Further, according to the first to third embodiments, the restriction plate 52 is provided at least at a position facing the end surface 22j1 of the downstream communication portion 22f and a position closest to the developer discharge port 22h.

  According to this configuration, even if the rotation speed of the second stirring member 44 changes and the amount of developer conveyed to the plurality of regulating plates 52 varies, the developer discharge is performed in the gaps S between the plurality of regulating plates 52. In order to suppress fluctuations in the amount of developer sent to the outlet 22h, excess developer can be stably discharged to the developer discharge port 22h.

  Moreover, according to the said 1st Embodiment, the some control board 52 consists of the three control boards 52a-52c which have the same outer diameter.

  According to this configuration, even if the rotation speed of the second stirring member 44 changes and the amount of developer conveyed to the plurality of regulation plates 52a to 52c varies, the gap S between the plurality of regulation plates 52a to 52c. In order to suppress fluctuations in the amount of developer sent to the developer discharge port 22h, excess developer can be discharged stably to the developer discharge port 22h.

  Further, according to the third embodiment, the restriction plate 52 is provided so that the outer diameter increases in order from the position facing the end surface 22j1 of the side wall portion 22j toward the developer discharge port 22h.

  According to this configuration, even if the rotation speed of the second stirring member 44 changes and the amount of developer conveyed to the plurality of regulating plates 52 varies, the developer discharge port is formed in the gap S between the plurality of regulating plates 52. In order to suppress fluctuations in the amount of developer sent to 22h, excess developer can be stably discharged to the developer discharge port 22h.

  In the above-described embodiment, the configuration in which the plurality of restriction plates 52 are composed of two or three restriction plates is shown. However, the present invention is not limited to this, and the plurality of restriction plates 52 is composed of four or more restriction plates. You may make it do. This configuration also has the same effect as the above embodiment.

    In the above-described two embodiments, the plurality of restricting plates 52 are configured by two restricting plates 52a and 52b having the same outer diameter. However, the present invention is not limited to this, and the two restricting plates 52a and 52b. May be configured such that the outer diameter increases in order from the upstream side of the transport path.

    In the above embodiment, the developing roller 20 and the magnetic roller 21 are provided, a magnetic brush is carried on the magnetic roller 21, only the toner is supplied to the developing roller 20, and the toner on the developing roller 20 is caused to fly to the photoreceptor. Although an example applied to a developing device has been shown, the present invention is not limited to this, and development is performed by pumping developer from a stirring member to a developing roller, and supplying only toner from the developer on the developing roller containing a magnet to the photoreceptor. You may apply to an apparatus.

  Hereinafter, Examples 1 to 4 that further embody the embodiment of the present invention and Comparative Example 1 will be described. In addition, this invention is not limited only to a following example.

  The developing roller 20 used in Examples 1 to 4 and Comparative Example 1 has an outer diameter of 16 mm and a rotation speed of 630 rpm, and the magnetic roller 21 has an outer diameter of 20 mm and a rotation speed of 800 rpm. In the first stirring member 43, the outer diameter of the first spiral blade 43a is 20 mm, the blade pitch is 30 mm (double winding), and the shaft diameter of the rotating shaft 43b is 7 mm. On the other hand, in the second stirring member 44, the outer diameter of the second spiral blade 44a is 20 mm, the blade pitch is 30 mm (double winding), and the shaft diameter of the rotating shaft 44b is 7 mm. Reverse rotation with respect to the blade 43a. The conveying blade 51 is composed of four blades having an outer diameter of 20 mm and a width (length in the axial direction) of 10 mm. The width (length in the axial direction) of the restriction space K is 12 mm.

  The toner in the developing container 22 has an average particle size of 6.8 μm, the carrier has an average particle size of 35 μm, and the weight ratio of the toner to the carrier is 9%. The weight ratio of the carrier to the toner of the new developer replenished in the developing container 22 was 10%. 400 g of developer is accommodated in the developer container 22 (first and second transport paths 22c and 22d), and this amount is a predetermined amount that does not contain excess developer in the developer container 22.

  In the above configuration, in Examples 1 to 3 and Comparative Examples 1 and 2, changes in the developer discharge amount with respect to the rotation speed of the second stirring member 44 were evaluated by changing the structure and arrangement of the regulating plate 52.

  As shown in FIG. 4, the plurality of restriction plates 52 according to the first embodiment includes three restriction plates 52 a to 52 c having the same outer diameter, each of which has a diameter of 20 mm, and each has a thickness. 2 mm. The interval between the restriction plates 52a and 52b and the interval between the restriction plates 52b and 52c are 2 mm, respectively. The distance between the regulating plate 52c and the developer discharge port 22h is 2 mm.

  As shown in FIG. 5, the plurality of restriction plates 52 according to the second embodiment are made of two restriction plates 52 a and 52 b having the same outer diameter, and are each a disk having an outer diameter of 20 mm, each having a thickness. 2 mm. The spacing between the regulating plates 52a and 52b is 6 mm, and the spacing between the regulating plate 52b and the developer discharge port 22h is 2 mm.

  As shown in FIG. 6, the plurality of restriction plates 52 according to the third embodiment includes three restriction plates 52 a to 52 c having different outer diameters. The outer diameter of the restriction plate 52 a is 10 mm, and the outside of the restriction plate 52 b. The diameter is 15 mm, and the outer diameter of the regulating plate 52c is 20 mm. Each regulation plate 52a to 52c has a thickness of 2 mm. The interval between the restriction plates 52a and 52b and the interval between the restriction plates 52b and 52c are 2 mm, respectively. The distance between the regulating plate 52c and the developer discharge port 22h is 2 mm.

  As shown in FIG. 7, the restriction plate 52 according to the fourth embodiment includes three restriction plates 52 a to 52 c having different outer diameters, and the outer diameter of the restriction plate 52 a is 20 mm. The outer diameter of the restricting plate 52b is 15 mm, and the outer diameter of the restricting plate 52c is 10 mm. Each regulation plate 52a to 52c has a thickness of 2 mm. The interval between the restriction plates 52a and 52b and the interval between the restriction plates 52b and 52c are 2 mm, respectively.

  As shown in FIG. 8, the restriction plate 52 according to the comparative example 1 is composed of one restriction plate, and is disposed in contact with the discharge blade 53 in the axial direction at a position facing the end surface 22j1 of the downstream side wall portion 22j. The The restricting plate 52 is a disc having an outer diameter of 20 mm and has a thickness of 2 mm.

  In Examples 1 to 4 and Comparative Example 1, FIG. 9 shows evaluation results of changes in the developer discharge amount with respect to changes in the rotation speed of the second stirring member 44. FIG. 9 is a graph in which the horizontal axis represents the rotation speed of the second stirring member 44 and the vertical axis represents the developer discharge amount per unit time, at each rotation speed with respect to the developer discharge amount at a rotation speed of 100 rpm. The developer discharge amount is shown. That is, the developer is discharged even at a rotation speed of 100 rpm, but since the discharge amount at the rotation speed of 100 rpm is a reference, the discharge amount on the graph is 0 g / min, and the discharge amount at other rotation speeds is the rotation The difference with respect to the discharge amount at a speed of 100 rpm is shown.

  As shown in FIG. 9, even when the rotation speed of the second stirring member 44 is increased, in Examples 1 to 4, the change in developer discharge amount is smaller than that in Comparative Example 1, and the developer discharge is stable. It was. In particular, in Examples 1 and 2, even when the rotation speed of the second stirring member 44 increases, the developer discharge amount hardly changes and the developer discharge is stable.

  INDUSTRIAL APPLICABILITY The present invention can be used for a developing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, and a composite machine using the electrophotographic method, and an image forming apparatus including the developing device. Can be used for a developing device that replenishes the two-component developer and discharges excess developer and an image forming apparatus equipped with the developing device.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2a-2d, 2 Developing apparatus 11a-11d, 11 Photoconductor 20 Developing roller 21 Magnetic roller 22 Developing container 22b Partition part 22c 1st conveyance path (Other conveyance path)
22d Second transport path (one transport path)
22e Upstream communication part 22f Downstream communication part (communication part)
22g Developer supply port 22h Developer discharge port 22i Upstream side wall 22j Downstream side wall (side wall)
22j1 end face 22k front wall portion 42 stirring member 43 first stirring member 43a first spiral blades 43b, 44b rotating shaft 44 second stirring member 44a second spiral blade (spiral blade)
51 Conveying blades 52, 52a to 52c Restriction plates 61 to 64 Gear K Restriction space S Clearance

Claims (5)

A developing device that stirs and conveys the developer and supplies the stirred developer to the developing roller,
A plurality of stirring members having a spiral blade extending in the axial direction around the rotation axis, and stirring and transporting the developer supplied to the developing roller;
A partition section that divides a conveyance path through which the developer is circulated and conveyed by each of the stirring members;
A communication part that is formed by the partition part and side wall parts provided on both end sides in the longitudinal direction, and communicates each of the transport paths;
A developer supply port for supplying developer to the transport path;
A developing device provided on the downstream side of any one of the transport paths and having a developer discharge port from which excess developer is discharged;
The stirring member disposed in the one transport path is provided to face the communication portion between the spiral blade and the developer discharge port, and is moved from the one transport path to the other transport path. A transport blade for transporting the developer through the communication portion;
A regulation plate that is provided between the conveying blade and the developer discharge port and restricts the movement of the developer from the conveying blade to the developer discharge port,
The developing device according to claim 1, wherein a plurality of the restriction plates are provided facing the side wall portion and spaced apart in the direction of the rotation axis.   2. The developing device according to claim 1, wherein the restriction plate is provided at a position facing at least an end surface of the side wall portion on a communication portion side and a position closest to the developer discharge port.   The developing device according to claim 2, wherein the plurality of restricting plates include three restricting plates having the same outer diameter.   The developing device according to claim 2, wherein the regulating plate is provided so that an outer diameter thereof increases in order from the position facing the end surface of the side wall portion on the communication portion side toward the developer discharge port. .   An image forming apparatus comprising the developing device according to claim 1.