JPH1124403A - Electrostatic latent image developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently stir a toner and carrier grains, to uniformly mix them and to surely electrify them by supplying the replenishing toner to the inside part of a first carrying path of a midstream carrying path and carrying it to a downstream carrying path through the first carrying path of the midstream carrying path, an upstream carrying path and a second carrying path of the midstream carrying path. SOLUTION: A developer stirring and carrying mechanism 40 is disposed behind a developer application means 24. Downstream, midstream and upstream carrying paths 42-46 are provided mutually in parallel in the front and rear direction. A toner supplied to the inside part of a first carrying path 441 in the midstream carrying path from a toner supply means is carried to the downstream carrying path 42 through the path 441 in the midstream carrying path, the upstream carrying path 46 and a second carrying path 442 in the midstream carrying path. Then, a developer transferred to the path 42 is carried toward both end parts from a central part in the shaft direction while being stirred by the action of first and second spiral blades 602 and 603 of a downstream stirring and carrying member 60. Besides, it is transferred backward and returned through developer transfer ports 484 and 485.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing apparatus for developing an electrostatic latent image into a toner image in an image forming machine such as an electrostatic copying machine or a laser printer.

[0002]

2. Description of the Related Art As is well known, in order to develop an electrostatic latent image in an image forming machine, an electrostatic latent image developing apparatus using a developer composed of toner and carrier particles has been widely used. I have. The electrostatic latent image developing device includes a developing housing for containing a developer, a developer applying unit for applying the developer in the developing housing to the electrostatic latent image, and agitating the developer in the developing housing. And a developer stirring / conveying mechanism for supplying the developer to the developer applying means. The developer applying means usually includes a rotating sleeve member, holds the developer on the peripheral surface of the sleeve member, conveys the developer to a developing area, and selects a toner in the developer into an electrostatic latent image in the developing area. The electrostatic latent image is developed into a toner image. When the toner in the developer is consumed according to the development of the electrostatic latent image, the toner is supplied from the toner supply device into the development housing.

In the above-described electrostatic latent image developing apparatus, the developer is sufficiently stirred before being transported to the developing area by being held by the developer applying means, so that the toner and the carrier particles are uniformly mixed. It is important that they are charged and charged. As described above, a developer stirring / conveying device that conveys a developer while satisfactorily stirring it is disclosed in, for example, JP-A-7-17
No. 5306 discloses this. JP-A-7-1753
Japanese Patent Application Publication No. 06-2006 discloses a spiral feeder for conveying a developer from a central portion toward both ends from a central portion to a downstream transport route, a midstream transport route, and an upstream transport route in a developing housing in parallel with a developer applying unit. A spiral winding for transporting a developer from both ends to a center portion of a downstream stirring and conveying member provided with a first spiral blade and a second spiral blade having winding directions opposite to each other in a middle flow path. A winding direction of a spiral that transports a developer from a central portion to both end portions of a middle flow stirring and transporting member having a first spiral blade and a second spiral blade formed in opposite directions to an upstream transport path. A first spiral blade and a second spiral blade formed opposite to each other are respectively provided with an upstream stirring and conveying member, and the upstream stirring and conveying member and the middle stirring and conveying member are conveyed to a downstream conveying path, Further, by the downstream stirring and conveying means Configuration the developer stirring and conveying device is disclosed as a developer to be fed is supplied to the developing agent application means.

[0004]

According to the developer stirring and conveying apparatus disclosed in the above publication, the developer is conveyed while being stirred through an upstream conveying path and a midstream conveying path to a downstream conveying path facing the developer applying means. A significant mixing and tribocharging effect is obtained. However, the toner supplied to the central portion of the upstream conveyance path is divided into two sides by the upstream stirring conveyance member, conveyed to both ends and sent to the middle conveyance path, and then from the both ends by the medium stirring conveyance member. Since the sheet is conveyed to the central portion and sent to the downstream conveyance path, it substantially passes only half of the upstream conveyance path and the middle conveyance path. Therefore, the developer stirring and conveying device disclosed in the above publication does not fully utilize the upstream conveyance path and the middle conveyance path as the conveyance path through which the developer is conveyed, and particularly when the transfer speed is increased. However, the mixing of the developer and the triboelectric charging effect are not always satisfactory. In addition,
In order to provide a sufficient transport path through which the developer is transported, each of the transport paths may be configured to be long. However, in a situation where the width direction dimension of the developing device is limited, the width direction dimension of the developing device is greater than The transport path cannot be made long.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a main technical problem thereof is to provide a developer stirring / conveying mechanism which can make a conveying path for conveying a developer as long as possible. To provide an electrostatic latent image developing device.

[0006]

According to the present invention, there is provided a developing housing for containing a developer comprising toner and carrier particles, and a developer in the developing housing. An electrostatic latent image developing apparatus comprising: a developer applying unit for applying an electrostatic latent image; and a developer stirring and conveying mechanism for conveying the developer in the developing housing to the developer applying unit while stirring the developer. The developer agitating transport mechanism includes a downstream transport path, a middle transport path, and an upstream transport path provided in the developing housing in parallel with the developer application unit; Downstream partition means disposed at a central portion and both sides thereof respectively having developer transfer ports, and upstream partition walls disposed between the middle flow path and the upstream transfer path and having respective developer transfer ports on both sides. Means of the downstream partition means A partition wall connecting one side edge of the developer transfer port provided in the center and the center of the upstream partition to partition the middle flow path into a first transfer path and a second transfer path; A rotary shaft provided in the downstream transport path, a first spiral blade and a first spiral blade provided on the rotary shaft and configured to reverse the spirals of the spirals for transporting the developer from the central portion toward both ends. A downstream agitating and conveying member having two spiral blades, a rotating shaft disposed in the middle flow path, and conveying the toner supplied to the first conveying path provided on the rotating shaft toward one end. A middle agitating / conveying member having a first spiral blade and a second spiral blade provided on the rotating shaft for transporting the developer from the other end of the second transport path toward the center, and the upstream transport path A rotary shaft disposed on the rotary shaft, and a spiral blade provided on the rotary shaft for conveying the developer from one end to the other end Comprising an upstream stirring and conveying member having, configured to supply toner to the inner part in the first transport path of the middle flow conveying path, an electrostatic latent image developing device is provided, characterized in that.

Further, according to the present invention, there is provided a developing housing for containing a developer comprising toner and carrier particles, a developer applying means for applying the developer in the developing housing to an electrostatic latent image, A developer stirring and conveying mechanism for conveying the developer in the developing housing to the developer applying unit while stirring the developer, wherein the developer stirring and conveying mechanism includes a developer stirring and conveying mechanism inside the developing housing. A downstream transfer path, a middle transfer path, and an upstream transfer path provided in parallel with the developer application unit, and a developer transfer port provided at the center and both sides provided between the downstream transfer path and the middle transfer path. Downstream partition means having, upstream partition means disposed between the middle transport path and the upstream transport path and having developer transfer ports on both sides thereof,
A rotary shaft provided in the downstream transport path, a first spiral blade provided on the transfer shaft and configured to reverse the winding directions of spirals for transporting the developer from a central portion to both ends, and A downstream stirring / conveying member provided with a second spiral blade, a rotating shaft provided in the midstream conveying path, and one of the developer transfer ports formed in a central portion of the downstream partition means on the rotating shaft; A rotary partitioning plate provided corresponding to the side edge of the first partition and dividing the midstream transport path into a first transport path and a second transport path; and one end provided with toner supplied to the rotary shaft and supplied to the first transport path. And a second spiral blade provided on the rotating shaft for transporting the developer from the other end of the second transport path toward the center. And a rotating shaft provided in the upstream transport path, and a developer provided on the rotating shaft, from one end to the other end. An upstream stirring and conveying member having a spiral blade that conveys the toner toward the inside, and configured to supply the toner to an inner portion of the first conveying path of the midstream conveying path. An image developing device is provided.
Other features of the present invention will become apparent from the following description.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electrostatic latent image developing device constructed in accordance with the present invention will be described below in further detail with reference to the accompanying drawings.

FIG. 1 shows a preferred embodiment of an electrostatic latent image developing apparatus constructed according to the present invention, together with a part of a rotating drum 2 constituting an image carrier. The rotating drum 2 is provided with an appropriate electrostatic photoreceptor on its peripheral surface, and is rotated in a direction indicated by an arrow 4 in the figure by an appropriate driving means (not shown) so as to pass through the developing area 6. Have been. In the developing area 6, the electrostatic latent image formed on the peripheral surface of the rotary drum 2 is developed into a toner image by an electrostatic latent image developing device generally designated by the numeral 8 according to the present invention. The toner image developed by the electrostatic latent image developing device is transferred to a transfer member such as plain paper by a transfer unit (not shown) on the downstream side of the developing area 6.
Then, the toner image transferred to the transfer member is heated and fixed by a fixing unit (not shown).

Referring to FIGS. 1 and 2, the electrostatic latent image developing device 8 includes a developing housing 10. The developing housing 10, which can be formed from a suitable synthetic resin, includes a front end wall 16 and a rear end wall 18 along with a bottom wall 12 and a rear wall 14 extending substantially vertically upward from the rear edge of the bottom wall 12. I have. The developing housing 10 thus configured is provided with an upper wall 20 and a cover member 22 formed of a synthetic resin that covers the upper surface thereof.

At the forefront of the developing housing 10 (the leftmost part in FIG. 1 and the uppermost part in FIG. 2), a developer applying means 24 is provided. The developer applying means 24 extends substantially horizontally in the developing region 6 in the width direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIG. 2) and is arranged in parallel with the rotary drum 2. It comprises a member 26 and magnet means 28 disposed in the sleeve member 26. The sleeve member 26 is formed of a non-magnetic material such as aluminum, and is rotatably mounted on the developing housing 10. The magnet means 28 is constituted by a stationary permanent magnet, and is fixed at a predetermined position in the sleeve member 26. As shown in FIG. 1, N poles and S poles are alternately formed on the outer peripheral surface of the stationary permanent magnet constituting the magnet means 28. As shown in FIG. 2, the rotation shaft 30 to which the sleeve member 26 is fixed is
0 through the rear end wall 18 so as to protrude rearward. An input gear (not shown) is fixed to the protruding end of the rotating shaft 30, and the input gear can be an electric motor via an appropriate transmission gear (not shown). Transmission). The sleeve member 2 of the first developer applying unit 24 thus configured
6 is driven to rotate in a direction indicated by an arrow 32 in FIG. 1, that is, in the developing area 6 in the same direction as the rotation of the rotary drum 2.

The free end 220 of the cover member 22 formed of a synthetic resin that covers the upper surface of the developing housing 10 is
A so-called ear-cutting means which is positioned close to the peripheral surface of the developer applying means 24 and regulates the amount of the developer held on the peripheral surface of the developer applying means 24 and conveyed to the developing area 6. Function as

A developer agitating / conveying mechanism 40 is provided behind the developer applying means 24. Developing housing 1
0, a downstream transport path 42, a midstream transport path 44, and an upstream transport path 46 are provided parallel to each other in the front-rear direction (the left-right direction in FIG. 1 and the up-down direction in FIG. 2).

A downstream partition means 48 is provided between the downstream transport path 42 and the middle transport path 44. This downstream partition means 48 is composed of a pair of partition walls 481 and 482, and is fixed to the bottom wall 12 of the developing housing 10 by a plurality of screws 49. The pair of partition walls 481,
482, as shown in FIG. 1, both lower end side surfaces are formed in a concave arc shape. In addition, a pair of partition walls 481 and 4
As shown in FIG. 2, opposing inner ends are provided at an interval from each other as shown in FIG. 2. Therefore, a developer transfer port 483 is formed at the center of the downstream partition means 48. 2 is provided between the outer ends of the pair of partition walls 481 and 482 and the front end wall 16 and the rear end wall 18 of the developing housing 10, respectively.
Are provided at predetermined intervals, and accordingly, developer transfer ports 484 and 485 are formed on both sides in the width direction of the downstream partition means 48, respectively.

An upstream partition means 50 is provided between the midstream transport path 44 and the upstream transport path 46. The upstream partition means 50 comprises a pair of partitions 501 and 502 in the illustrated embodiment.
0 is fixed to the bottom wall 12 by a plurality of screws 49. As shown in FIG. 1, both side surfaces of the lower end of the pair of partition walls 501 and 502 are formed in a concave arc shape. As shown in FIG. 2, the pair of partition walls 501 and 502 are provided with opposing inner ends thereof at a distance from each other.
3 are formed. In addition, a pair of partition walls 501 and 502
A predetermined distance is provided between each outer end of the developing housing 10 and the front end wall 16 and the rear end wall 18 of the developing housing 10 as shown in FIG. Are provided with developer transfer ports 504 and 505, respectively. The developer transfer port 504 provided at one end of the upstream partition means 50 is formed to be larger than the width of the developer transfer port 484 provided at one end of the downstream partition means 50. . In the illustrated embodiment,
The example in which the upstream partition means 50 is constituted by a pair of partitions 501 and 502 and the developer transfer port 503 is provided in the central portion is shown. However, the upstream partition means 50 is constituted by an integral partition and the developer transfer port in the central portion is necessarily provided. There is no.

At the center of the middle flow path 44, the inside end of one partition 481 (one side edge of the developer transfer port 483) of the downstream partition 50 and the upstream partition 5
0 is connected to the inner end of the other partition 502 (the other side edge of the developer transfer port 503) to partition the middle flow path 44 into a first transfer path 441 and a second transfer path 442 at the center. A partition 52 is provided. In the illustrated embodiment, the partition wall 52 is, as shown in FIG.
And an upper side wall 522. The lower side wall 521 is fixed to the bottom wall 12 of the developing housing 10 by a plurality of screws 54, and has a semicircular concave portion 521 on its upper surface.
a is provided. The upper side wall 522 has a semicircular concave portion 522a formed on the lower surface thereof corresponding to the concave portion 521a provided on the lower side wall 521, and the lower surface is placed on the upper surface of the lower side wall 521, as follows. It is fixed. The upper side wall 522 is provided with screw insertion holes 522b and 522b composed of a large-diameter hole and a small-diameter hole, and the screws 55 and 5 are inserted through the screw insertion holes 522b and 522b.
5, the upper side wall 522 is fixed to the lower side wall 521.
The plugs 56, 56 are fitted to the upper ends of the screw insertion holes 522b, 522b after the screws 55, 55 are tightened. The partition wall 52 configured as described above is formed in a triangular shape when viewed from above, and the second transport path 442
The side is an inclined guide surface.

A downstream stirring and conveying member 60 is disposed in the downstream conveying path 42. As shown in FIG. 2, the downstream stirring and conveying member 60 has a rotating shaft 601 rotatably mounted between both end walls 16 and 18 of the developing housing 10. A pair of a first spiral blade 602 and a second spiral blade 603 are formed on the rotating shaft 601 in the axial direction. First spiral blade 602 and second spiral blade 603
Are formed in mutually opposite winding directions. The outer diameter of the first spiral blade 602 and the outer diameter of the second spiral blade 603 are the same. The inner ends in the width direction of each of the first spiral blade 602 and the second spiral blade 603 are connected to the downstream partitioning means 48.
It is preferable to be located substantially corresponding to the center of the developer transfer port 483 provided at the center of the image forming apparatus. The outer ends in the width direction of the first spiral blade 602 and the second spiral blade 603 are located substantially at the center in the width direction of the developer transfer ports 484 and 485 provided at both ends in the width direction of the downstream partition wall means 48, respectively. Correspondingly located. The first spiral blade 60 is provided at both ends of the rotating shaft 601.
The first auxiliary spiral blade 604 and the second auxiliary spiral blade 6 located opposite to the second and second spiral blades 603, respectively.
05 is formed. This first auxiliary spiral blade 604
The second auxiliary spiral blade 605 has the same outer diameter as the outer diameters of the first spiral blade 602 and the second spiral blade 603, and is configured over an angle range of approximately 360 degrees. ing. Note that the winding directions of the first auxiliary spiral blade 604 and the second auxiliary spiral blade 605 are the same as those of the first spiral blade 602 and the second spiral blade 603 facing each other.
Is opposite to the winding direction.

A midstream stirring and conveying member 62 is provided in the midstream conveying path 44. The middle flow stirring and conveying member 62 has a rotating shaft 621 rotatably mounted between both end walls 16 and 18 of the developing housing 10. A pair of first spiral blades 622 and second spiral blades 623 are formed on the rotating shaft 621 at intervals in the axial direction, that is, in the width direction. The winding directions of the first spiral blade 622 and the second spiral blade 623 are formed in the same direction.
The outer diameter of the first spiral blade 622 and the outer diameter of the second spiral blade 623 are the same, and also the outer diameter of the first spiral blade 602 and the second spiral blade 603 of the downstream stirring and conveying member 60 described above. The diameter is larger than the diameter. In addition, the midstream stirring and conveying member 62 is provided to penetrate the partition wall 52. Therefore, in assembling, before the upper side wall 522 constituting the partition wall 52 is mounted, the middle flow stirring and conveying member 62 is disposed at a predetermined position of the developing housing 10 and the central portion of the rotating shaft 621 is provided on the lower side wall 521. The upper side wall 522 is then fixed to the lower side wall 521 by the screws 55 and 55 as described above. Then, the plugs 56, 56 are mounted on the upper ends of the screw insertion holes 522b, 522b.

The upstream conveying path 46 is provided with an upstream stirring conveying member 64. The upstream stirring and conveying member 64 has a rotating shaft 641 rotatably mounted between both end walls 16 and 18 of the developing housing 10. The rotary shaft 641 has a spiral blade 642 in the axial direction, that is, the entire width direction.
Are formed. The outer diameter of the spiral blade 642 is smaller than the outer diameters of the spiral blades 622 and 623 of the midstream stirring and conveying member 62 and larger than the outer diameters of the spiral blades 602 and 603 of the downstream partitioning means 48.

The rotating shaft 601 of the downstream stirring and conveying member 60
The rotation shaft 621 of the middle-flow stirring conveyance member 62 and the rotation shaft 641 of the upstream stirring conveyance member 64 penetrate the rear end wall 18 of the developing housing 10 and protrude rearward. , 621 and 641 are fixed at their rear ends with input gears (not shown), respectively.
This input gear is operatively connected to an appropriate transmission mechanism for driving an input gear (not shown) fixed to the rotating shaft 30 of the developer applying unit 24. The downstream stirring / conveying member 60, the midstream stirring / conveying member 62, and the upstream stirring / conveying member 64 configured as described above are respectively indicated by arrows 60 in FIG.
It is driven to rotate in the directions indicated by 0, 620 and 640.

Referring to FIGS. 1 and 2, the bottom wall 12 of the developing housing 10 is located at a position facing the inside of the second transport path 442 in the middle transport path 44.
A circular opening 12a is formed. And this opening 1
The detector 2a is provided with a detector 66 for detecting the toner concentration in the developer 100 composed of the carrier particles and the toner contained in the developing housing 10. The detector 66 has an upper surface exposed in the second transport path 442 in the middle stream transport path 44 through the opening 12a, and detects the magnetic permeability of the developer 100 present on the upper surface to detect the magnetic flux in the developer 100. Detecting the toner density of the toner may be in a known form. The electrostatic latent image developing device 8 further includes a developer 100 detected by the detector 66.
There is also provided a toner supply device that is operated in accordance with the toner concentration in the toner. This toner supply device includes a feed pipe 70 provided on the upper wall 20 of the developing housing 10. One end of the feed pipe 70 is located above the middle flow path 44, and a lower surface thereof has a feed port 70 a at a position facing the inside of the first transfer path 441 in the upstream middle flow path 44. Is formed. The other end of the feeding pipe 70 extending from the one end to the front end in the width direction is communicated with a toner container (not shown), and the toner conveying means which can be constituted by a spiral blade in the feeding pipe 70. (Not shown) are provided. When the toner concentration in the developer 100 detected by the detector 66 becomes equal to or lower than a predetermined value, the toner conveying means in the feeding pipe 70 is operated, and the toner is conveyed from the toner container through the feeding pipe 70, and the toner is conveyed. The developer is dropped from the outlet 70a to the inside of the first transport path 441 in the middle transport path 44 in the developing housing 10. When the toner concentration detected by the detector 100 becomes equal to or higher than a predetermined value, the operation of the toner conveying means in the supply pipe 70 is stopped, and the supply of the toner into the developing housing 10 is stopped.

Next, the operation and effect of the electrostatic latent image developing device 8 as described above will be summarized and described as follows. The toner dropped from a delivery port 70a formed in the delivery pipe 70 of the toner supply means is supplied to the middle flow path 4
4 and is conveyed in one direction (left direction in FIG. 2) as indicated by an arrow in FIG. 2 by the action of the first spiral blade 622 of the middle-flow stirring conveyance member 62. . The toner conveyed in one direction in the first conveyance path 441 in the middle conveyance path 44 and conveyed to one end thereof is conveyed by the downstream stirring conveyance member 60 and passes through the developer transfer port 484 to the first toner in the middle conveyance path 44. Along with the developer transferred to one end (the left end in FIG. 2) of the transport path 441, the developer is sent to one end (the left end in FIG. 2) of the upstream transport path 46 through the developer transfer port 503.

The developer and toner transported to one end of the upstream transport path 46 are transferred to the spiral blade 642 of the upstream stirring transport member 64.
While being agitated and mixed by the action of (1), it is conveyed toward the other end (the right end in FIG. 2). A part of the developer and the toner conveyed from one end to the other end of the upstream conveyance path 46 pass through the middle conveyance path 44 through a developer transfer port 503 provided at the center of the upstream partitioning means 50. At the inner end of the first transport path 441. In this manner, the developer conveyed to the other end of the upstream conveyance path 46 by the upstream stirring conveyance member 64 is conveyed to the other end of the second conveyance path 442 in the middle conveyance path 44 through the developer transfer port 504. The supplied developer is conveyed by the second spiral blade 603 of the downstream stirring and conveying member 60 and is transferred to the developer transfer port 485.
With the developer transferred to the other end (the right end in FIG. 2) of the second transport path 442 in the middle flow transport path 44, the developer is stirred and mixed by the action of the second spiral blade 623 of the middle flow stirring transport member 62. The paper is conveyed toward the inner end of the two conveyance path 442 (the center of the middle conveyance path 44). Then, the developer transported to the inner end of the second transport path 442 in the middle stream transport path 44 is transported to the downstream transport path 42 through the developer transport port 483.

The developer transported to the downstream transport path 42 is transported from the axial center to both axial ends while being stirred by the action of the first and second spiral blades 602 and 603 of the downstream stirring transport member 60. Is done. Then, the developer transported to both ends in the axial direction is transported backward through the developer transport ports 484 and 485, and the second transport in the middle transport path 44 and one end of the first transport path 441 in the middle transport path 44. It is returned to the other end of the road 442.

As described above, the delivery pipe 7 of the toner supply means
The toner supplied from 0 to the inside of the first conveyance path 441 in the middle conveyance path 44
Since the sheet is conveyed to the downstream conveyance path 42 via the conveyance path 441, the second conveyance path 442 in the upstream conveyance path 46, and the middle conveyance path 44, the conveyance path is compared with the above-described prior art having the conveyance path of the same length. It is doubled. Therefore, the toner and the carrier particles can be sufficiently stirred, and the toner and the carrier particles are uniformly mixed and charged reliably.

Referring to FIGS. 1 and 2, the description will proceed to the downstream side of the downstream transport path 42 (the left side in FIG.
(Upper side), the sleeve member 26 of the developer applying unit 24 is rotated in the direction indicated by the arrow 32. In the developer pumping area indicated by reference numeral 241 in FIG. 1, while being stirred by the action of the first spiral blade 602 and the second spiral blade 603 of the downstream stirring and transporting member 60, the developer is transported from the axial center to both ends. Developer 100
Is pumped to the peripheral surface of the sleeve member 26 due to the magnetic field formed by the magnet means 28. The developer 100 pumped to the peripheral surface of the sleeve member 26 is conveyed in the direction indicated by the arrow 32 in association with the rotation of the sleeve member 26, and is conveyed to the development area 6. At this time, due to the action of the free edge 220 of the cover member 22 of the developing housing 10, the excess developer 100 is removed from the peripheral surface of the sleeve member 26.
Is removed. In the developing area 6, as described above, the toner in the developer is selectively adhered to the electrostatic latent image formed on the peripheral surface of the electrostatic photosensitive member provided on the rotating drum 2, and The electrostatic latent image is developed into a toner image. In the developer peeling area 242 located downstream of the developing area 6, the developer 1 is removed from the peripheral surface of the sleeve member 26 due to the magnetic field formed by the magnet means 28 being reduced.
00 is released. The toner density of the developer 100 is reduced due to consumption of the toner in the developing area 6. The developer 100 released from the peripheral surface of the sleeve member 26 is mixed with the developer 100 in the developing housing 10 and is agitated by the action of the first spiral blade 602 and the second spiral blade 603 of the downstream stirring and conveying member 60. While being conveyed to both ends in the axial direction, the developer is returned to one end of the first conveyance path 441 in the middle flow path 44 and the other end of the second conveyance path 442 in the middle flow path 44 through the developer transfer ports 484 and 485.

Next, another embodiment of the present invention will be described with reference to FIG. In the embodiment shown in FIG. 4, the same members as those of the embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted. The embodiment shown in FIG. 4 is different from the embodiment shown in FIGS. 1 to 3 in that the partition wall 52 for partitioning the intermediate flow path 44 into a first transport path 441 and a second transport path 442 is eliminated. A rotary partitioning machine 62 is provided at the center of the
4 is provided, and the middle partitioning path 4
4 is divided into a first transport path 441 and a second transport path 442. This rotary partitioning machine 624
Is provided corresponding to the inner end (one side edge of the developer transfer port 483) of the one partition wall 481 of the downstream partition wall means 50 on the rotating shaft 621 constituting the middle flow stirring transport member 62. Further, in the present embodiment, the second partition 623 conveys the surface of the rotary partitioning machine 624 facing the second spiral blade 623 from the other end of the second transport path 442 toward the center. An auxiliary spiral blade 625 that pushes the developer back to the other end is provided.

Next, the operation and effect of the developer stirring / conveying mechanism 40 of the electrostatic latent image developing device 8 in the embodiment shown in FIG. 4 will be briefly described as follows. The toner dropped from the delivery port 70a formed in the delivery pipe 70 of the toner supply means and the developer existing in each transport path are supplied to the first spiral blade 622 of the middle flow agitating transport member 62 and the upstream agitating transport member 64. 4, the second spiral blade 623 of the middle flow stirring and conveying member 62, and the first and second spiral blades 602 and 603 of the downstream stirring and conveying member 60, as shown by arrows in FIG. Conveyed. Note that, in this embodiment, while being stirred and mixed by the action of the second spiral blade 623 of the middle-flow agitating / conveying member 62, the other end of the second conveyance path 442 moves from the other end to the inner end (the center of the middle-flow conveyance path 44). The developer conveyed toward is pushed back by the auxiliary spiral blade 625 provided on the rotary partition 624, so that the developer is surely transferred to the downstream conveyance path 42 through the developer transfer port 483.

[0029]

The electrostatic latent image developing device according to the present invention is constructed as described above, and has the following effects.

That is, in the electrostatic latent image developing apparatus according to the present invention, the replenishment toner is supplied to the inside of the first transport path in the intermediate transport path, and the first transport path, the upstream transport path, and the intermediate transport path in the intermediate transport path. Since the sheet is conveyed to the downstream conveyance path via the second conveyance path in the path, the conveyance path is doubled as compared with the prior art having the same length of conveyance path. Therefore, the toner and the carrier particles can be sufficiently stirred, and the toner and the carrier particles are uniformly mixed and charged reliably.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of an electrostatic latent image developing device configured according to the present invention.

FIG. 2 is a plan view omitting a cover member that covers an upper surface of a developing housing of the electrostatic latent image developing device shown in FIG.

FIG. 3 is a sectional view taken along line AA in FIG. 1;

FIG. 4 is a sectional view showing another embodiment of the electrostatic latent image developing device constituted according to the present invention.

[Explanation of symbols]

 2: rotating drum 6: developing area 8: electrostatic latent image developing device 10: developing housing 20: upper wall 22: cover member 24: developer applying unit 26: sleeve member 28: magnet unit 30: rotating shaft 42 of the sleeve member : Downstream transport path 44: Midstream transport path 46: Upstream transport path 48: Downstream partition means 50: Upstream partition means 52: Partition partition 60: Downstream stirring transport member 601: Downstream stirring transport member rotating shaft 602: Downstream stirring transport First spiral blade of member 603: Second spiral blade of downstream stirring / conveying member 62: Midstream stirring / conveying member 621: Rotating shaft of midstream stirring / conveying member 622: First spiral blade of midstream stirring / conveying member 623: Midstream stirring Second spiral blade 64 of the conveying member: upstream stirring and conveying member 641: rotating shaft of the upstream stirring and conveying member 642: spiral blade of the upstream stirring and conveying member 624: rotary partitioning machine 625: auxiliary spiral blade 66: toner concentration detector

Claims (3)

[Claims] 1. A developing housing for housing a developer comprising toner and carrier particles, a developer applying unit for applying the developer in the developing housing to an electrostatic latent image, and a developing device in the developing housing. A developer agitating and transporting mechanism for transporting the developer to the developer applying means while agitating the developer, wherein the developer agitating and transporting mechanism is parallel to the developer applying means in the developing housing. A downstream transport path, a middle transport path, and an upstream transport path provided in the downstream partition wall means disposed between the downstream transport path and the middle transport path and having a developer transfer port at each of a central portion and both sides; An upstream partition means disposed between the middle transport path and the upstream transport path and having a developer transfer port on each side; and one of a developer transfer port provided at a central portion of the downstream partition means Side edge and the center of the upstream partition And a partition wall for dividing the midstream transport path into a first transport path and a second transport path; a rotating shaft disposed in the downstream transport path; A downstream stirring / conveying member including a first spiral blade and a second spiral blade in which the spiral directions of the spirals conveyed toward the section are formed to be opposite to each other, and a rotating shaft disposed in the midstream conveying path. A first spiral blade provided on the rotation shaft for conveying the toner supplied to the first conveyance path toward one end, and a developer provided on the rotation shaft from the other end of the second conveyance path. A midstream stirring / conveying member having a second spiral blade for conveying toward the central portion, a rotating shaft disposed on the upstream conveying path, and a developer provided on the rotating shaft, from one end to the other end. And an upstream stirring and conveying member having a spiral blade for conveying toward the first conveying path of the middle conveying path. Kicking and configured to supply toner to the inner portion, an electrostatic latent image developing device, characterized in that. 2. A developing housing for containing a developer comprising toner and carrier particles, a developer applying means for applying the developer in the developing housing to an electrostatic latent image, and a developing device in the developing housing. A developer agitating and transporting mechanism for transporting the developer to the developer applying means while agitating the developer, wherein the developer agitating and transporting mechanism is parallel to the developer applying means in the developing housing. A downstream transport path, a middle transport path, and an upstream transport path provided in the downstream partition wall means disposed between the downstream transport path and the middle transport path and having a developer transfer port at each of a central portion and both sides; An upstream partition means disposed between the middle transport path and the upstream transport path and having a developer transfer port on each side; a rotating shaft disposed in the downstream transport path; The developer from the center to both ends A downstream stirring and conveying member including a first spiral blade and a second spiral blade in which the spiral directions of the spirals to be fed are formed to be opposite to each other; a rotating shaft disposed in the middle flow path; The middle flow path is provided corresponding to one side edge of the developer transfer port formed at the center of the downstream partition means.
A rotary partitioning plate for partitioning a transport path and a second transport path, a first spiral blade provided on the rotary shaft for transporting toner supplied to the first transport path toward one end, and a rotary blade provided on the rotary shaft; A middle agitating and conveying member having a second spiral blade that conveys the developer from the other end of the second conveying path toward the center thereof; a rotating shaft disposed in the upstream conveying path; An upstream agitating and conveying member provided with a spiral blade for conveying the developer from one end to the other end provided on the shaft, and supplying the toner to an inner portion of the first conveying path of the middle flow path. An electrostatic latent image developing device having a configuration as described above. 3. The medium-flow agitating / conveying member has a second spiral blade on a surface of the rotary partitioning machine facing the second spiral blade and extends from the other end to the center of the second transport path. The electrostatic latent image developing device according to claim 2, further comprising an auxiliary spiral blade that pushes the developer conveyed back to the other end.