JPH086394A - Developer stirring/conveying device - Google Patents

Abstract

PURPOSE:To provide a developer stirring/conveying device capable of thoroughly stirring and mixing a toner and carrier grains in the right and left regions and suppressing the deterioration of the carrier. CONSTITUTION:This developer stirring/conveying device is provided with at least one bulkhead arranged in a housing and having developer shift ports at the center section, the first stirring/conveying member 62 arranged along the bulkhead on one side of the bulkhead and having the first spiral blade 76 and the second spiral blade 78 conveying the developer to the center section from both end sections, and the second stirring/conveying member 64 arranged along the bulkhead on the other side of the bulkhead and conveying the developer to both end sections from the center section. The first spiral blade 76 and the second spiral blade 78 provided on the first stirring/conveying member 62 are formed with half-pitch spiral blades 702, 722, 862, 882 with their inner end sections set at the phase angle of about 180 deg. each other.

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 device used for developing an electrostatic latent image into a toner image in an image forming machine such as an electrostatic copying machine and an electrostatic printing machine. The present invention relates to a developer stirring and transporting device equipped.

[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 device using a developer composed of toner and carrier particles is widely put into practical use. . This electrostatic latent image developing device includes a developing housing for containing a developer, a developer applying means for applying the developer in the developing housing to the electrostatic latent image, and agitating the developer in the developing housing. Further, it is provided with a developer stirring / conveying device for conveying in a required direction, and a toner supplying means for supplying toner into the developing housing. The developer applying means usually includes a rotating sleeve member, and the developer is held on the peripheral surface of the sleeve member and conveyed to the developing area, and the toner in the developer is selected as an electrostatic latent image in the developing area. Are electrostatically adhered, and the electrostatic latent image is developed into a toner image. When the toner in the developer is consumed in the development of the electrostatic latent image, the toner is supplied from the toner supply unit into the developing housing. The developer agitating / conveying device agitates the developer in the developing housing to mix and triboelectrically charge the toner and carrier particles and convey the toner and carrier particles in a predetermined direction.

In the electrostatic latent image developing device of the above-described form, the developer is sufficiently agitated before being held by the developer applying means and conveyed to the developing area, and the ratio of the toner to the carrier particles is increased. It is important that the developer which is within the required range and is sufficiently uniformly mixed is applied to the electrostatic latent image. Further, on the downstream side of the developing area, the toner with which the toner is attached to the electrostatic latent image and thus the ratio of the toner is reduced is effectively separated from the developer applying means, and is re-emitted in the developing housing. It is important to be stirred and transported. In order to meet such requirements as to stirring and carrying of the developer, JP-B-50-27333.
Japanese Patent Application Laid-Open No. 3-260678 and Japanese Patent Application Laid-Open No. 3-260678 each include a developing device including a first agitating / conveying member extending adjacent to a developer applying unit and a second agitating / conveying member disposed upstream thereof. An agent stirring and conveying device is disclosed. The first agitating / conveying member is formed with a rotary shaft extending in the width direction (that is, the axial direction of the rotary sleeve member in the developer applying means) and an axial gap with respect to the rotary shaft, and the winding directions are opposite to each other. The second agitating / conveying member is also composed of a pair of spiral blades, and the second stirring / transporting member also extends in the width direction and a pair of winding shafts which are axially spaced apart from each other and whose winding directions are opposite to each other. Composed of spiral blades. The first agitating / conveying member is rotated in a predetermined direction and conveys the developer from both axial end portions toward the central portion in the axial direction while agitating the developer, and the developing agent is conveyed to the central portion in the axial direction of the first agitating / conveying member. Transfer. Similarly, the second agitating / conveying member, which is rotated in a predetermined direction, conveys the developer from the central portion in the axial direction toward both ends in the axial direction while agitating the developer, and the first agitating / conveying member in both ends in the axial direction. The developer is transferred to the member. The developer being conveyed from the central portion in the width direction to both ends in the axial direction by the second agitating and conveying member is held by the developer applying means and conveyed to the developing area. Further, in the above-mentioned Japanese Patent Laid-Open No. 3-260678, an inclined elliptical plate is arranged between a pair of spiral blades on the rotation axis of the second stirring and conveying member, and the first stirring and conveying member is provided with one end portion to a central portion. Distribute the transported developer to both sides of the second stirring and transporting member, and distribute the developer transported from the other end of the first stirring and transporting member to the central portion to both sides of the second stirring and transporting member. Thus, it is also disclosed that the developer is allowed to flow between one side and the other side in the width direction to make the developer uniform in the entire width direction.

[0004]

However, in the developer agitating and conveying device disclosed in Japanese Utility Model Publication No. 50-27333, the developer in the left and right areas is circulated only in each area, and the developing in both areas is performed. There is a problem that the developer does not mix positively, and only the toner concentration of the developer in one region may decrease. On the other hand, in the developer stirring / conveying device disclosed in Japanese Patent Laid-Open No. 3-260678, an inclined elliptical plate is arranged between a pair of spiral blades on the rotating shaft of the second stirring / conveying member to make the first stirring. Since the developer transported from one end of the transport member to the center is distributed to both sides of the second stirring and transporting member, the toner concentration of the developer in the left and right regions can be made uniform. it can. However, since the force of stirring the developer by the rotation of the inclined elliptical plate acts in the direction perpendicular to the elliptical plate, the clearance angle of the developer is small, and therefore, there is a problem that the deterioration of the developer, especially the carrier, is promoted. . When the carrier deteriorates, the coating agent on the surface of the carrier is peeled off, fine toner particles are attached, the carrier surface is contaminated by the toner material, and the like, so that the charging ability of the carrier is lowered and the toner holding power is lowered. When the toner holding power of the carrier is reduced, the charge characteristics of the toner are not stable, the charge amount is small, the charge amount distribution is wide, and there are physical changes such as zero charge and increase of reverse charge toner, resulting in non-image. Problems such as so-called toner fog phenomenon in which toner adheres to the area and toner scattering occur.

The present invention has been made in view of the above facts, and its technical problem is that the toner and carrier particles in the left and right regions are sufficiently mixed and the toner adhesion region is unevenly distributed on one side in the axial direction. Even when the latent image is developed, it is sufficiently suppressed that the mixing ratio of the toner and the carrier particles in the developer becomes non-uniform in the axial direction, and even if such non-uniformity occurs, it can be resolved promptly. It is an object of the present invention to provide a developer agitating / conveying device capable of suppressing deterioration of the carrier.

[0006]

In order to solve the above technical problems, according to the present invention, at least one partition wall provided in the housing and having a developer transfer port in the center, and the partition wall. A first stirring and conveying member having a first spiral blade and a second spiral blade arranged on one side of the partition wall to transport the developer from both ends toward the central part, and the other side of the partition wall. A second agitating / conveying member having a first spiral blade and a second spiral blade for conveying the developer from the central portion toward both end portions, the first agitating / conveying member being disposed along the partition wall. The first spiral blade and the second spiral blade provided on the agitating / conveying member are constituted by half-pitch spiral blades whose inner end portions have a phase angle of approximately 180 degrees with each other, respectively. A carrier device is provided.

Further, according to the present invention, the upstream partition wall and the downstream partition wall, which are arranged in parallel in the housing at a distance and each provided with a developer transfer port in the central portion, the upstream partition wall and the downstream partition wall. And a first agitating / conveying member provided with a first spiral blade and a second spiral blade for conveying the developer from both ends toward the central portion, and the first stirring / conveying member on the downstream side of the downstream partition wall. A second agitating / conveying member that is provided along the downstream partition wall and that has a first spiral blade and a second spiral blade that transports the developer from the central portion toward both ends, and the upstream side of the upstream partition wall. And a third agitating / conveying member provided with a first spiral blade and a second spiral blade, the third agitating / conveying member being disposed along the upstream partition wall for conveying the developer from the central portion toward both ends. The first spiral blade and the second spiral blade provided on the first stirring / conveying member are Part is configured with a phase angle of approximately 180 degrees by the half pitch spiral blade together, developer stirring and conveying device is provided, characterized in that.

[0008]

In the developer agitating and conveying device of the present invention, the first
Of the developer that is conveyed toward the central portion in the axial direction by the first spiral blade of the agitating and conveying member, and the developer that is conveyed toward the central portion in the axial direction by the second spiral blade of the first agitating and conveying member. When it reaches the inner end where the half-pitch spiral blade is present, it is conveyed on the half-pitch spiral blade, but is not conveyed in the part without the half-pitch spiral blade. Therefore, in the portion where the half-pitch spiral blade is located, the developer conveyed by the spiral blade on the side where the half-pitch spiral blade is present is conveyed beyond the axial center. Since the half-pitch spiral blades are arranged with a phase angle of approximately 180 degrees with each other, the above-described operation is alternately performed with the rotation of the half-pitch spiral blades, and thus the first pitch is conveyed from one area. And the developer conveyed by the second spiral blade from the other region are mixed at substantially the same ratio, and the developers in the left and right regions are made uniform. In this way, the first
The developer transported to the central portion in the axial direction of the stirring and transporting member of
It is transferred to the second stirring and conveying member side through a developer transfer port provided in the central portion of the partition wall, and from the central portion to both ends by the first spiral blade and the second spiral blade of the second stirring and conveying member. It is transported toward.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a developer agitating / conveying device constructed according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an electrostatic latent image developing device provided with a developer agitating / conveying device constructed according to the present invention together with a part of a rotary drum constituting an electrostatic copying machine.
The rotating drum 2 having an appropriate electrostatic photosensitive member arranged on the peripheral surface is rotated in the direction indicated by an arrow 4 to move to the developing area 6
Is configured to pass through. On the upstream side of the developing area 6, an electrostatic latent image is formed on the peripheral surface of the rotary drum 2 by an appropriate method known per se. In the developing zone 6, an electrostatic latent image developing device, generally designated by reference numeral 8, provided with a developer stirring and conveying device 7 constructed according to the present invention converts the electrostatic latent image on the peripheral surface of the rotary drum 2 into a toner image. To be developed. Such a toner image is transferred to a transfer member such as plain paper on the downstream side of the developing area 6 and fixed there, thus obtaining a copy or a printed matter.

Continuing the description with reference to FIGS. 1 and 2,
The electrostatic latent image developing device 8 includes a developing housing 10. A developer housing 10, which may be molded from any suitable synthetic resin, includes a bottom wall 12 and a rear wall 16 extending substantially vertically upward from a rear edge of the bottom wall 12 as well as a front end wall 18 and a rear end wall 20. There is. An upper wall 22 is connected to the rear wall 16 so as to project substantially horizontally from the upper end of the rear wall 16, and a cover wall 24 is further connected to the upper wall 22.

A developer applying means 26 is disposed at the frontmost portion (the leftmost portion in FIG. 1 and the uppermost portion in FIG. 2) of the developing housing 10. The developer applying means 26 is composed of a sleeve member 28 extending substantially horizontally in the width direction and a permanent magnet member 30 arranged in the sleeve member 28. The sleeve member 28 is made of a non-magnetic material such as aluminum and is rotatably mounted.
The permanent magnet member 30 is fixed at a predetermined position. As shown in FIG. 2, the rotary shaft 31 to which the sleeve member 28 is fixed penetrates the rear end wall 20 of the developing housing 10 and projects rearward, and the projecting end portion thereof has the input gear 3
2 is fixed. The input gear 32 is drivingly connected to a rotary drive source (not shown), which may be an electric motor, through an input gear (not shown) of the rotary drum 2, and is driven to rotate in a direction indicated by an arrow 34. To be Free edge 35 of cover wall 24 of developer housing 10
Is located in the vicinity of the peripheral surface of the sleeve member 28 of the developer applying means 26, and as will be described in more detail later, is held on the peripheral surface of the sleeve member 28 and conveyed to the developing area 6. It functions as a so-called panning means for controlling the amount of the agent.

Behind the developer applying means 26, a developer stirring and conveying device 7 constructed according to the present invention is arranged. In the illustrated embodiment, the developer agitating / conveying device 7 is provided with an upstream side partition wall 38 which is disposed in parallel with the developing housing 10 in the front-rear direction (left-right direction in FIG. 1, up-down direction in FIG. 2) at a predetermined interval. And a downstream side partition wall 40. The upstream partition 38 is the bottom wall 1 of the developing housing 8.
2 is defined by upstanding walls 42 and 44 which project substantially vertically upwards from 2. Similarly, the downstream-side partition wall means 40 also has the upright walls 46 and 4 projecting substantially vertically from the bottom wall 12 of the developing housing 8.
8 is defined. As can be clearly understood from FIG. 1, the lower end side surfaces of each of the upright walls 42, 44, 46 and 48 are concave arc-shaped. As is clearly understood by referring to FIG. 2, the width direction (direction perpendicular to the paper surface in FIG. 1, left-right direction in FIG. 2)
Upright walls 42 and 4 at the center and both ends in the width direction
4 does not exist, and the developer transfer ports 50, 52 and 5 are provided at the widthwise central portion and both widthwise end portions of the upstream partition 38, respectively.
4 are provided. Similarly, the upright walls 46 and 48 do not exist at the widthwise central portion and both widthwise end portions, and the developer transfer ports 56, 58 and 60 are provided at the widthwise central portion and the widthwise both ends of the downstream partition 40, respectively. Is provided. The widthwise dimension W2 of the developer transfer port 56 provided in the widthwise central portion of the downstream partition 40 is the widthwise dimension of the developer transfer port 50 provided in the widthwise central portion of the upstream partition 38. It is set to be larger than W1, and the relationship between the widthwise dimensions W2 and W1 is set depending on various factors such as the size of the apparatus and the copying speed. W2 is 1. of the widthwise dimension W1.
It is preferably 3 to 4.0 times, preferably 1.5 to 2.5 times. The widthwise direction of the developer transfer ports 52 and 54 provided at both widthwise ends of the upstream partition 38 and the widthwise direction of the developer transfer ports 58 and 60 provided at both widthwise ends of the downstream partition 40. All dimensions may be substantially the same,
It is preferable that it is substantially the same as the widthwise dimension W2 of the developer transfer port 56 provided in the widthwise central portion of the downstream side partition wall 40.

The developer agitating / conveying device 7 shown in the figure has a first agitating / conveying member 62 disposed between the upstream partition 38 and the downstream partition 40, and a downstream side of the downstream partition 40 ( That is, the second side disposed along the downstream partition 40 on the front side)
Of the agitating and conveying member 64 and the third partitioning member disposed on the upstream side (ie, the rear side) of the upstream partition wall 38 along the upstream partition wall 38.
The agitating and conveying member 66 is provided. The first agitating and conveying member 62, the second agitating and conveying member 64, and the third agitating and conveying member 66 are arranged on the same plane in the illustrated embodiment.

The first agitating / conveying member 62 has a rotary shaft 68 rotatably mounted between both end walls 18 and 20 of the developing housing 10. A pair of a first spiral blade 70 and a second spiral blade 72 are formed on the rotary shaft 68 at intervals in the axial direction. The outer diameters of the first spiral blade 70 and the second spiral blade 72 are the same,
The spiral winding directions are opposite to each other. As clearly shown in FIG. 3, the first spiral blade 70 and the second spiral blade 70
The inner end portion of the spiral blade 72 is composed of half-pitch spiral blades 702 and 722. It is important that the half pitch spiral blades 702 and 722 are arranged with a phase angle of approximately 180 degrees with respect to each other. The inner ends of the first spiral blade 70 and the second spiral blade 72, that is, the inner ends of the half-pitch spiral blades 702 and 722 are both spaced from the axial center of the first stirring and conveying member 62 by a predetermined distance. Therefore, the mixing portion 210 is provided between the inner end of the first spiral blade 70 and the inner end of the second spiral blade 72 at the central portion in the axial direction of the first stirring and conveying member 62. Has been formed. The first developer agitating / conveying member 62 configured as described above is
It is rotated in the direction shown by the arrow 108 in FIG.
The developer is conveyed from both ends toward the center while stirring.

The second agitating / conveying member 64 also has a rotary shaft 74 rotatably mounted between the end walls 18 and 20 of the developing housing 10. A pair of a first spiral blade 76 and a second spiral blade 78 are formed on the rotary shaft 74 at intervals in the axial direction. This first spiral blade 76
The second spiral blade 78 and the second spiral blade 78 have the same outer diameter, and the spiral winding directions are opposite to each other. First
The inner end of the spiral blade 76 and the inner end 2 of the second spiral blade 78 are respectively arranged at a predetermined distance from the axial center of the second stirring and conveying member 64, and therefore, Second
A mixing portion 220 is formed between the inner end of the first spiral blade 76 and the inner end of the second spiral blade 78 at the axial center of the stirring and conveying member 64. The first end is provided on both ends of the rotary shaft 74.
The first auxiliary spiral blade 80 and the second auxiliary spiral blade 82 are formed to face the spiral blade 76 and the second spiral blade 78, respectively. The outer diameters of the first auxiliary spiral blade 80 and the second auxiliary spiral blade 82 may be the same as the outer diameters of the first spiral blade 76 and the second spiral blade 78. The winding directions of the first auxiliary spiral blade 80 and the second auxiliary spiral blade 82 extending over an angle range of approximately 360 degrees are the winding directions of the first spiral blade 76 and the second spiral blade 78 facing each other. And in the opposite direction. The second developer agitating / conveying member 64 thus configured is rotated in the direction indicated by an arrow 110 in FIG. 1, and conveys the developer from the central portion toward both ends while stirring.

Continuing the description with reference to FIG.
The agitating and conveying member 66 also has a rotating shaft 84 rotatably mounted between the both end walls 18 and 20 of the developing housing 10. A pair of a first spiral blade 86 and a second spiral blade 88 are formed on the rotary shaft 84 at intervals in the axial direction. The first spiral blade 86 and the second spiral blade 88
And have the same outer diameter, and the winding directions of the spiral are opposite to each other. The inner ends of the first spiral blade 86 and the second spiral blade 88 are constituted by half-pitch spiral blades 862 and 882. It is important that the half pitch spiral blades 862 and 882 are arranged with a phase angle of approximately 180 degrees with respect to each other. First spiral blade 8
6 and the inner ends of the second spiral blades 88, that is, the inner ends of the half-pitch spiral blades 862 and 882, are arranged at predetermined intervals from the axial center of the third stirring and conveying member 66. Therefore, the inner end of the first spiral blade 86 and the second spiral blade 8 are provided at the central portion in the axial direction of the first stirring and conveying member 66.
A mixing section 230 is formed between the inner end of the inner part 8 and the inner end of the part 8. First
The outer ends of the spiral blade 86 and the second spiral blade 88 in the axial direction correspond to the widthwise intermediate portions of the developer transfer ports 52 and 54 arranged at both ends in the width direction of the upstream partition means 38. Conveniently located. A first auxiliary spiral blade 90 and a second auxiliary spiral blade 92 are formed at both ends of the rotary shaft 84 so as to face the first spiral blade 86 and the second spiral blade 88, respectively. First auxiliary spiral blade 90
And the outer diameter of the second auxiliary spiral blade 92 is equal to that of the first spiral blade 8
6 and the outer diameter of the second spiral blade 88 may be the same. About 36
First auxiliary spiral blade 90 extending over an angle range of 0 degrees
The winding direction of the second auxiliary spiral blade 92 is opposite to the winding direction of the opposing first spiral blade 86 and second spiral blade 88. The third developer agitating / conveying member 66 thus configured is rotated in the direction indicated by the arrow 106 in FIG. 1, and conveys the developer from the central portion toward both ends while stirring.

Referring to FIG. 2 and FIG. 5, the first description will be made.
Each of the rotating shaft 68 of the stirring and conveying member 62, the rotating shaft 74 of the second stirring and conveying member 64, and the rotating shaft 84 of the third stirring and conveying member 66 penetrates the rear end wall 20 of the developing housing 10 to the rear. These rotating shafts 68 are projected,
At the rear ends of 74 and 84 are input gears 98, 100, respectively.
102 is fixed. The input gear 102 is the input gear 9
8 and the input gear 98 is the input gear 1
00, and the input gear 100 is engaged with the input gear 32 of the developer applying means 26 via the transmission gear 104 rotatably mounted on the rear end wall 20. Accordingly, when the sleeve member 28 of the developer applying means 26 is rotated in the direction indicated by the arrow 34 by the above-mentioned rotary drive source (not shown), the first stirring and conveying member 62 is indicated by the arrow 108 as shown in FIG. The second agitating / conveying member 64 is rotated in the direction indicated by the arrow, and the third agitating / conveying member 66 is rotated in the direction indicated by the arrow 106.

As shown in FIG. 1, the developing housing 10
A developer 112 composed of toner and carrier particles is contained therein. The developer 112 is provided on the upstream side (the right side in FIG. 1, the lower side in FIG. 2) of the upstream partition 38, between the upstream partition 38 and the downstream partition 40, and the downstream partition 40.
Are appropriately dispersed and accommodated on the downstream side (left side in FIG. 1, upper side in FIG. 2). The third agitating / conveying member 66 rotated in the direction indicated by the arrow 106 conveys the developer from the central portion in the axial direction toward both ends in the axial direction while stirring the developer on the upstream side of the upstream partition wall 38. That is, the first spiral blade 86 of the third stirring / conveying member 66 conveys the developer from the central portion in the axial direction to the one end portion in the axial direction (the left end portion in FIG. 2) while stirring the developer, and the third stirring / conveying member. The second spiral blade 88 of the member 66 conveys the developer from the central portion in the axial direction to the other end portion in the width direction (the right end portion in FIG. 2) while stirring the developer. Third
The first auxiliary spiral blade 90 of the agitating / conveying member 66 forcibly forces the developer axially inward at one end in the width direction, and the first auxiliary spiral blade 92 axially injects the developer at the other axial end. Force one. The first agitating / conveying member 62 rotated in the direction indicated by the arrow 108 conveys the developer from both axial end portions toward the axial central portion while agitating the developer between the upstream partition wall 38 and the downstream partition wall 40. To do. That is, the first spiral blade 70 of the first stirring / conveying member 62 conveys the developer while stirring the developer from one axial end (the left end in FIG. 2) toward the axial central portion, and the first stirring / conveyance is performed. The second spiral blade 72 of the member 62 conveys the developer while stirring. Arrow 1
Second agitating / conveying member 64 rotated in the direction 10
Conveys the developer from the central portion in the axial direction toward both ends in the axial direction while stirring the developer on the downstream side of the downstream partition wall 40.
That is, the first spiral blade 76 of the second stirring / transporting member 64 transports the developer while stirring the developer from the central portion in the axial direction toward one end portion (the left end portion in FIG. 2) in the axial direction, and the second stirring / transporting member. The second spiral blade 78 of the member 64 conveys the developer from the central portion in the axial direction to the other end portion in the axial direction (the right end portion in FIG. 2) while stirring the developer. First of the second stirring and conveying member 64
The auxiliary spiral blade 80 of FIG. 2 forces the developer axially inward at one end in the axial direction, and the second auxiliary spiral blade 82 forces the developer axially inward at the other end of the axial direction.

The carrying capacity of the first agitating and carrying member 62 for carrying the developer from both axial end portions toward the axial central portion is as follows.
The second stirring and conveying member 64 and the third stirring and conveying member 66 which convey the developer from the central portion in the axial direction toward both end portions in the axial direction.
It is important that they are set to be larger than their respective carrying capacities. Substantially balance the transport of the developer from both axial ends to the axial center and the transport of the developer from the axial center to both axial ends to make the developer sufficiently uniform throughout the axial direction. In order to exist, the carrying capacity of the first stirring and carrying member 62 is made to substantially match the sum of the carrying capacity of the second stirring and carrying member 64 and the carrying capacity of the third stirring and carrying member 66. Is preferred. Further, it is preferable that the carrying capacity of the second agitating / conveying member 64 is set to be larger than the carrying capacity of the third agitating / conveying member 66, and the carrying capacity of the second agitating / conveying member 64 is the third. It is expediently about 1.2 to 2.5 times the carrying capacity of the agitating and carrying member 66 (the reason for which will be further mentioned later). The transport capacities of the first agitating / conveying member 62, the second agitating / conveying member 64, and the third agitating / conveying member 66 are the same as those of the first and the second.
The spiral blades 70 and 72, 76 and 78, and 86 and 88 can be set as required by appropriately setting the rotation speed, pitch, and outer diameter. In the illustrated embodiment, the number of revolutions of the second stirring / conveying member 64 per unit time is the same as the number of revolutions of the third stirring / conveying member 66 per unit time. The number of rotations of the agitating and conveying member 62 per unit time is set to be large. The pitch of the first and second spiral blades 76 and 78 of the second stirring and conveying member 64 is set to the third stirring and conveying member 66.
Is larger than the pitch of the first and second spiral blades 86 and 88, and the pitch of the first and second spiral blades 70 and 72 of the first stirring and conveying member 62 is the same as that of the first and second spiral conveying members 64. It is even larger than the second spiral vanes 76 and 78.
The first and second spiral blades 86 of the third stirring and conveying member 66
And 88 and the outer diameters of the first and second spiral blades 76 and 78 of the second stirring and conveying member 64 are the same, but the first stirring and conveying member 62 first and second are larger than these outer diameters. The outer diameter of the second spiral blades 70 and 72 is large.

Continuing the description with reference to FIGS. 1 and 2,
A circular opening 114 is formed in the bottom wall 12 of the developing housing 10 between the upstream partition wall 38 and the downstream partition wall 40 and in the center portion in the width direction. Then, the detector 114 for detecting the toner concentration in the developer 112 is provided in the opening 114.
16 are provided. This detector 116 has an aperture 11
The toner concentration in the developer 112 can be detected by detecting the magnetic permeability of the developer 112 existing on the upper surface exposed in the developing housing 10 through the structure 4 in itself. The electrostatic latent image developing device 8 further includes the developer 11 detected by the detector 116.
There is also provided a toner supply means which is operated depending on the toner concentration in the toner. The toner supply unit includes a feeding pipe 118 arranged on the upper wall 22 of the developing housing 10. One end of this feed pipe 118 is
The third agitating / conveying member 66 is located above the central portion in the axial direction, and a delivery port 120 communicating with the inside of the developing housing 10 is formed on the lower surface thereof. The other end of the feeding pipe 118 extending from the one end to the front end in the width direction is communicated with a toner container (not shown).
A toner conveying means (not shown), which can be constituted by a spiral blade, is arranged in the unit 18. When the toner concentration in the developer 112 detected by the detector 116 becomes a predetermined value or less, the toner conveying means in the feeding pipe 118 is operated to convey the toner from the toner container through the feeding pipe 118 and feed it. From the outlet 120 to the development housing 1
It is made to fall on the central part of the third stirring and conveying member 66 within 0. When the toner density detected by the detector 116 becomes equal to or higher than a predetermined value, the operation of the toner conveying means in the feeding pipe 118 is stopped, and the toner supply to the developing housing 10 is stopped.

Next, the operation and effect of the electrostatic latent image developing device 8 provided with the developer agitating and conveying device 7 as described above will be summarized and described as follows. As shown by the arrow in FIG. 2, the toner dropped from the delivery port 120 formed in the delivery pipe 118 of the toner supply means is mixed with the developer 112 in the development housing 10. The developer 112 existing on the upstream side (on the right side in FIG. 1) of the upstream partition wall 38 is agitated by the action of the first and second spiral blades 86 and 88 of the third agitating / conveying member 66, and the central portion in the axial direction. Is conveyed to both sides in the axial direction. Since the carrying capacity of the third agitating / conveying member 66 is set to be relatively small, the developer 112 is carried by the third agitating / conveying member 66 from the central portion in the width direction to both side portions in the width direction at a relatively low speed. At this time, it can be sufficiently stirred. The developer 11 that has been conveyed to both sides in the axial direction by the third stirring and conveying member 66.
2 is transferred to the front through the developer transfer ports 52 and 54 provided on both sides in the width direction of the upstream partition 38,
It is introduced between the upstream partition 38 and the downstream partition 40.

Next, the upstream partition 38 and the downstream partition 40
Between the developer 112 and the first stirring and conveying member 6
While being agitated by the action of the first and second spiral blades 70 and 72, the second spiral blades 70 are conveyed from both axial side portions to the axial central portion. First spiral blade 70 of first stirring and conveying member 62
Developer conveyed toward the central portion in the axial direction by the
When the developer conveyed toward the central portion in the axial direction by the second spiral blade 72 of the first agitating / conveying member 62 reaches the inner end portion where the half-pitch spiral blades 702 and 722 are present,
It is conveyed on the half-pitch spiral blade, but is not conveyed on the part without the half-pitch spiral blade. Therefore, as shown in FIG. 3, in the portion where the half-pitch spiral blade 702 or 722 is located, the developer conveyed by the spiral blade on the side where the half-pitch spiral blade 702 or 722 is present exceeds the axial center. It is conveyed to the mixing unit 201. Since the half-pitch spiral blades 702 and 722 are arranged with a phase angle of approximately 180 degrees with respect to each other, the above-mentioned operation is achieved.
02 and 722 are alternately performed, so that the developer carried by the first spiral blade 70 from one area and the developer carried by the second spiral blade 72 from the other area are mixed. In the portion 201, they are mixed at substantially the same ratio, and the developers in the left and right regions are made uniform. In this way, the developer conveyed to the mixing chamber 201 is transferred to the mixing section 202 of the second stirring and conveying member 64 through the developer transfer port 56 provided in the central portion of the downstream partition 40,
Further, a part of the developer is transferred to the mixing section 203 of the third stirring / transporting member 66 through the developer transfer port 56 provided at the center of the upstream partition wall 38. Since the widthwise dimension W2 of the developer transfer port 56 formed in the downstream side partition means 40 is set to be relatively large, a relatively large amount of the developer 112 passes through the developer transfer port 56 and the downstream partition means. It is made to enter the downstream side of 40. Since the width W1 of the developer transfer port 56 formed in the upstream partition means 38 is set to be relatively small, the developer 112 returned to the upstream side of the upstream partition means 38 through the developer transfer port 56 is A relatively small amount of toner, and also the toner dropped from the above-mentioned toner outlet 120,
It is surely avoided that the third agitating / conveying member 66 directly introduces the developer through the developer transfer port 50 between the upstream side partition 38 and the downstream side partition 40 without being agitated and conveyed. To be done.

The developer transferred to the front from the developer transfer port 56 provided in the widthwise central portion of the downstream side partition wall 40 has the first spiral blade 76 and the second spiral blade 76 of the second agitating and conveying member 64. While being agitated by the action of the spiral blade 78, it is conveyed from the central portion in the axial direction to both side portions in the axial direction. Then, the developer 112 conveyed to the both side portions in the axial direction receives the downstream partition 40.
Is transferred rearward through the developer transfer ports 58 and 60 disposed on both sides in the width direction of the sheet, and is returned between the upstream partition wall 38 and the downstream partition wall 40, and then the first stirring and conveying member 62. First spiral blade 70 and second spiral blade 72 of
While being agitated by the action of, the toner is conveyed from both axial side portions to the axial central portion.

Continuing the description with reference to FIGS. 1 and 2,
The downstream side of the third stirring and conveying member 64 (the left side in FIG. 1,
2, the sleeve member 28 of the developer applying unit 26 is rotated in the direction indicated by the arrow 34. In the developer scooping area indicated by the reference numeral 122 in FIG. 1, both sides in the axial direction from the central portion in the axial direction while being stirred by the action of the first spiral blade 76 and the second spiral blade 78 of the second stirring and conveying member 64. Part of the developer 112 conveyed to the portion is pumped up to the peripheral surface of the sleeve member 28 due to the magnetic field formed by the stationary permanent magnet member 30. The developer 112 pumped up to the peripheral surface of the sleeve member 28 is accompanied by the rotation of the sleeve member 28 and the arrow 34.
It is conveyed in the direction indicated by and is conveyed to the developing area 6. At this time, the free edge 3 of the cover wall 24 of the developing housing 10
By the action of 5, the excess developer 112 is removed from the peripheral surface of the sleeve member 28. In the developing area 6, as described above, the toner in the developer 112 is selectively adhered to the electrostatic latent image formed on the peripheral surface of the rotary drum 4, so that the electrostatic latent image becomes a toner image. It is developed. In the developer peeling area 124 located downstream of the developing area 6, the magnetic field formed by the permanent magnet member 30 is reduced, and so on.
12 is released. The toner density of the developer 112 is reduced due to the consumption of toner in the developing area 6. The developer 112 separated from the peripheral surface of the sleeve member 28 is mixed with the developer 112 in the developing housing 10 and is acted by the action of the first spiral blade 76 and the second spiral blade 78 of the second stirring and conveying member 64. It is conveyed to both sides in the axial direction while being stirred. Since the carrying capacity of the second stirring and carrying member 64 is set to be larger than the carrying capacity of the third stirring and carrying member 66, the developer peeling area 1
At 24, the developer 112 is satisfactorily separated from the peripheral surface of the sleeve member 28, and the developer 112 is mixed into the developer 112 in the developing housing 10 sufficiently quickly and stirred.

The present invention has been described above based on the illustrated embodiments, but the present invention is not limited to the embodiments, and various modifications can be made within the scope of the technical idea of the present invention. In the above embodiment, an example in which three stirring / conveying members are used has been shown, but two or more stirring / conveying members may be used.

[0027]

The developer agitating / conveying device according to the present invention is constructed as described above, and the inner ends of the first spiral blade and the second spiral blade provided on the first agitating / conveying member are mutually opposite. Since the half-pitch spiral blade is formed with a phase angle of about 180 degrees, the developer conveyed by the spiral blade on the side where the half-pitch spiral blade is present is axial in the portion where the half-pitch spiral blade is located. Transported over the center. Since this action is alternately performed with the rotation of the half-pitch spiral blade, the developer conveyed by the first spiral blade from one area and the developer conveyed by the second spiral blade from the other area. Are mixed in a substantially equal ratio, and the developers in the left and right regions are made uniform. Therefore, even when the electrostatic latent image in which the toner adhesion region is unevenly distributed on one side in the width direction is developed, it is possible to sufficiently suppress the non-uniform mixing ratio of the toner and the carrier particles in the developer, and tentatively the toner and the carrier particle. Even if the mixing ratio with the particles becomes uneven in the width direction, such unevenness can be quickly eliminated. Moreover, the action of transporting the developer in one region beyond the center in the axial direction by the half-pitch spiral blade of the first spiral blade of the first stirring and conveying member and the half-pitch spiral blade on the side of the second spiral blade The action of transporting the other area developer beyond the center in the axial direction is performed by the phase difference between the half-pitch spiral blades, and therefore promotes the deterioration of the developer, especially the carrier, as in the conventional inclined elliptical plate. But also
The developer transferred from the central portion in the axial direction of the first stirring / transporting member to the second stirring / transporting member (and the third stirring / transporting member) is forced to change its direction like the conventional inclined elliptical plate. The second agitating / conveying member (and the third agitating / conveying member) smoothly conveys it as it is from the central portion in the axial direction to both ends in the axial direction, so that deterioration of the carrier is suppressed and the carrier is excellent for a long time. Can be made to function.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an electrostatic latent image developing device equipped with a developer stirring and conveying device configured according to the present invention.

FIG. 2 is a plan view showing an electrostatic latent image developing device equipped with a developer agitating / conveying device configured according to the present invention shown in FIG. 1 while omitting an upper wall of a developing housing, a cover member and the like.

FIG. 3 is a plan view of a main portion of a first stirring / conveying member in the developer stirring / conveying device shown in FIG.

FIG. 4 is a simplified diagram showing a drive connecting gear in the electrostatic latent image developing device shown in FIG.

[Explanation of symbols]

 2: rotating drum 6: developing area 7: developer stirring and conveying device 8: electrostatic latent image developing device 10: developing housing 26: developer applying means 28: sleeve member 30: permanent magnet member 38: upstream partition wall 40: downstream Side wall 42: Upright wall 44: Upright wall 46: Upright wall 48: Upright wall 50: Developer transfer port 52: Developer transfer port 54: Developer transfer port 56: Developer transfer port 58: Developer transfer port 60: Developer transfer port 62: First stirring and conveying member 64: Second stirring and conveying means 66: Third stirring and conveying means 68: Rotating shaft 70: First spiral blade 72: Second spiral blade 74: Rotating shaft 76: 1st spiral blade 78: 2nd spiral blade 80: 1st auxiliary spiral blade 82: 2nd auxiliary spiral blade 84: rotating shaft 86: 1st spiral blade 88: 2nd spiral blade 90: First auxiliary spiral blade 92: Second Auxiliary spiral blade 112: Developer 116: Detector (toner concentration detector) 118: Toner supply means delivery pipe 120: Outlet 702: Half-pitch spiral blade 722: Half-pitch spiral blade 862: Half-pitch spiral blade 882: Half Pitch spiral blade

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Motoyuki Fukuda 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (72) Mitsuhiro Kashihara 1-228 Tamatsukuri, Chuo-ku, Osaka Within Mita Engineering Co., Ltd.

Claims (6)

[Claims] 1. At least one partition wall provided in the housing and provided with a developer transfer port in the central portion, and one partition wall along one of the partition walls along which the developer is loaded from both end portions to the central portion. A first stirring / transporting member having a first spiral blade and a second spiral blade for transporting the developer toward the other side; and a developer disposed on the other side of the partition along the partition to direct the developer from the center to both ends. A second agitating / conveying member having a first spiral blade and a second spiral blade for conveying, wherein the first spiral blade and the second spiral blade provided on the first agitating / conveying member respectively include A developer agitating / conveying device, wherein inner end portions are constituted by half-pitch spiral blades having a phase angle of approximately 180 degrees with each other. 2. An upstream-side partition wall and a downstream-side partition wall, which are arranged in parallel in a housing at intervals and each of which has a developer transfer port in the center, and are arranged between the upstream-side partition wall and the downstream-side partition wall. And the first spiral blade and the second spiral blade that convey the developer from both ends toward the center.
A first agitating / conveying member having a spiral blade; a first spiral blade disposed downstream of the downstream partition wall along the downstream partition wall and transporting the developer from the central portion toward both ends; A second agitating and conveying member having a second spiral blade; a first spiral arranged upstream of the upstream partition wall along the upstream partition wall and transporting the developer from the central portion to both end portions; A third agitating / conveying member having a blade and a second spiral conveying member, wherein the first spiral blade and the second spiral blade provided on the first agitating / conveying member have inner ends thereof mutually A developer agitating / conveying device comprising a half-pitch spiral blade having a phase angle of about 180 degrees. 3. The carrying capacity of the first stirring and carrying member is:
The developer stirring / conveying apparatus according to claim 2, wherein the conveying capacity of the second stirring / conveying means and the conveying capacity of the third stirring / conveying member are set to be larger than those of the third stirring / conveying member. 4. The carrying capacity of the first stirring and carrying member is:
4. The developer stirring and conveying device according to claim 3, wherein the sum of the conveying ability of the second stirring and conveying means and the conveying ability of the third stirring and conveying member is substantially matched. 5. The carrying capacity of the second stirring and carrying member is:
The developer agitating / conveying device according to claim 2, wherein the developer agitating / conveying device is set to have a larger capacity than that of the third agitating and conveying member. 6. The widthwise dimension of the developer transfer port provided in the downstream partition is set to be larger than the widthwise dimension of the developer transfer port provided in the upstream partition. The developer stirring and conveying device described.