JPH1031351A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing costs and to make a developing device sufficiently compact by reducing ear cutting torque. SOLUTION: The developing device is provided with a first sleeve member 28 and a second sleeve member 40. An ear cutting member 120 having a leading end edge near the surface of the second sleeve member 40 is arranged on the upstream side of a developing area 6 and in a part nearer to the upstream side than the nearest part 122 of the second sleeve member 40 and the first sleeve member 28, when viewed in the rotational direction 48 of the second sleeve member 40. Further, a developer stirring/carrying means 74 including a first rotary helical blade means 80 extended along the second sleeve member 40 is disposed on the upstream side of the ear cutting member 120, when viewed in the rotational direction 48 of the second sleeve member 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing an electrostatic latent image into a toner image in an image forming machine such as an electrostatic copying machine and a laser printer, and more particularly, to a developing device for developing two electrostatic latent images. The present invention relates to a developing device provided with an agent applying unit.

[0002]

2. Description of the Related Art In an image forming machine such as an electrostatic copying machine and a laser printer, as is well known, an electrostatic latent image is formed on an image bearing member, and then the electrostatic latent image is converted into a toner image. Developing. Such development is accomplished by applying a developer on the image bearing member as the image bearing member is moved through the development zone. Japanese Patent Application Laid-Open No. Sho 60-115972 discloses a developing device which applies a developer to an image bearing member to develop an electrostatic latent image into a toner image. There is disclosed an embodiment provided with two developer application units, that is, a second developer application unit. Such a developing device is configured such that when the image bearing member (rotary drum) is moved downward through the developing area, the first developer applying means and the second developer applying means apply carrier particles on the image bearing member. The electrostatic latent image is developed into a toner image by applying a developer consisting of a toner and a toner.

More specifically, the first developer applying means in the developing device comprises a first sleeve member which is driven to rotate, and a first magnet means disposed in the first sleeve member. Have been. Similarly to the first developer applying means, the second developer applying means also includes a second sleeve member which is driven to rotate and a second magnet means provided in the second sleeve member. ing. In the development area, the image bearing member is moved downward, and the second sleeve member is disposed below the first sleeve member. The surfaces of the first sleeve member and the second sleeve member are moved in the forward direction with respect to the movement of the image bearing member in the development area.

[0004] The developing device is also provided with a developer stirring and conveying means. The developer stirred and conveyed by the developer stirring and conveying means is magnetically attracted and held on the surface of the second sleeve member. Next, the developer sucked and held on the surface of the second sleeve member is located on the upstream side of the developing area when viewed in the rotation direction of the second sleeve member and at the closest distance between the second sleeve member and the first sleeve member. Upstream from the site, it is transferred to the surface of the first sleeve member, magnetically attracted and held there, and applied on the image bearing member in the development zone.
Next, the developer that has been suction-held on the surface of the first sleeve member is transferred to the surface of the second sleeve member, is suction-held there, and is applied onto the image bearing member in the development area.

In the second sleeve member, the magnetic attraction force for attracting the developer to the surface of the second sleeve member is reduced or significantly reduced downstream of the developing area when viewed in the rotation direction of the second sleeve member. A developer peeling area is generated. The developer sucked and held on the surface of the second sleeve member,
The developer is separated from the surface in the developer peeling area, and is mixed with the developer which has been stirred and transported by the action of the developer stirring and transporting means.

[0006] The developing device described above is provided with a cutting member for regulating the amount of developer sucked and held on the surface of the first sleeve member. The ear cutting member has a leading edge close to the surface of the first sleeve member on the upstream side of the developing area when viewed in the rotation direction of the first sleeve member. The ear-cutting member acts on the developer which is magnetically held and moved on the surface of the first sleeve member to remove excess developer from the first sleeve member and remove the excess developer from the surface of the first sleeve member. The developer held thereon is regulated to an appropriate layer thickness. Therefore, the layer thickness of the developer transferred from the surface of the first sleeve member to the second sleeve member and held on the surface by suction is substantially the same as that of the developer held on the surface of the first sleeve member. The thickness is regulated.

[0007]

In the developing device of the above-described embodiment, the developer is applied on the image bearing member without excessively increasing the diameters of the first and second sleeve members of the developer applying means. The length of the developing region (the length in the moving direction of the image carrying member) can be considerably increased, and therefore, there is an advantage that good development can be realized despite its relatively compact size. .

However, the above-described developing device still has the following problems to be solved. That is, as described above, the ear cutting member acts on the developer that is magnetically held and moved on the surface of the first sleeve member,
Excess developer is removed from the first sleeve member, and the developer retained on the surface of the first sleeve member is regulated to an appropriate layer thickness. Therefore, the developer magnetically held and moved on the surface of the first sleeve member is forcibly dammed except for the layer thickness portion by the front cutting member. A pool of agent is created.
As a result, the cutting torque (rotation torque) of the first sleeve member increases, and the size of a rotation drive source including an electric motor or the like for driving the rotation member including the first sleeve member increases. Also, accompanying the increase in the size of the rotary drive source, it is necessary to increase the strength of the drive system. Therefore, the manufacturing cost of the apparatus becomes relatively expensive, and further, the downsizing of the apparatus is limited, and there is a possibility that the sufficient downsizing, which is an advantage of the developing device of the above-described embodiment, may not be achieved.

The present invention has been made based on the above-mentioned facts, and a main object of the present invention is to reduce the production cost by lowering the head-cutting torque and to make the developing device sufficiently compact. It is to provide.

[0010]

According to the present invention, an electrostatic latent image formed on an image bearing member that is moved through a developing area is transferred to the image bearing member on the image bearing member in the developing area by using carrier particles and toner. A developing device for developing a toner image by applying a developer consisting of a first sleeve member that is driven to rotate and a first magnet unit that is disposed inside the first sleeve member. One developer applying unit, a second developer applying unit including a second sleeve member driven to rotate and a second magnet unit disposed in the second sleeve member, and a developer. Stirring and conveying means,
In the development zone, the image bearing member is moved downward, the second sleeve member is disposed below the first sleeve member, and the first sleeve member and the second sleeve member are Each surface is moved forward in the development zone with respect to the movement of the image bearing member, developer is magnetically attracted to the surface of the second sleeve member, and then the second sleeve member The developer sucked and held on the surface is located on the upstream side of the developing area when viewed in the rotation direction of the second sleeve member and at a position closer to the closest position between the second sleeve member and the first sleeve member. On the upstream side, transferred to the surface of the first sleeve member and magnetically attracted and held there, applied on the image bearing member in the development zone;
Next, the developer continuously sucked and held on the surface of the first sleeve member is transferred to the surface of the second sleeve member, sucked and held there, and developed on the image bearing member in the developing area. In the apparatus, the second sleeve member is located on the upstream side of the developing region as viewed in the rotation direction of the second sleeve member and on the upstream side of the closest portion between the second sleeve member and the first sleeve member. A first edge cutting member having a leading edge close to the surface of the sleeve member and regulating the amount of developer sucked and held on the surface of the second sleeve member; A first rotating helical blade means adjacent to and extending along the second sleeve member upstream of the first cutting member as viewed in the direction of rotation of the second sleeve member; One rotating spiral blade means Ri, the developer dammed upstream of said first ear switching member, allowed to flow along said second sleeve member, a developing device, characterized in that, is provided.

The first cutting member acts on the developer magnetically held and moved on the surface of the second sleeve member to remove excess developer from the second sleeve member, The developer held on the surface of the sleeve member is regulated to an appropriate layer thickness. Therefore, the developer that is magnetically held and moved on the surface of the second sleeve member is forcibly blocked by the first cutting member except for the layer thickness portion. A pool of developer is about to be created upstream of the member. However, in the above invention, the first rotary spiral blade means is adjacent to and extends along the second sleeve member on the upstream side of the first cutting member in the rotation direction of the second sleeve member. The first rotating spiral blade means is arranged to cause the developer blocked upstream of the first ear cutting member to flow along the second sleeve member by the stirring / transporting action. It is configured. Since the cutting torque of the second sleeve member is reduced due to the flow of the developer, a rotation drive source including an electric motor for driving a rotation member including the second sleeve member is provided. Is downsized. Then, it is not necessary to increase the strength of the drive system accompanying the downsizing of the rotary drive source. Therefore, the manufacturing cost of the apparatus is reduced, and the apparatus is downsized, so that the developing apparatus of the above-described embodiment is sufficiently compacted.

According to the present invention, in addition to the above configuration,
An upstream end of the developing area as viewed in the rotation direction of the first sleeve member has a leading edge close to the surface of the first sleeve member, and is suction-held on the surface of the first sleeve member. A second cutting member for regulating the amount of developer is provided, and a gap between the leading edge of the first cutting member and the surface of the second sleeve member is formed by the second cutting member. A developing device is provided, wherein the gap is set larger than a gap between the leading edge and the surface of the first sleeve member.

In the present invention, a relatively coarse amount of developer is regulated with respect to the second sleeve member by the first ear cutting member, and is regulated by the second ear cutting member with respect to the first sleeve member. The final regulation of the amount of developer is performed. The cutting torque of the second sleeve member is reduced for the reasons described above, but the restriction of the amount of the developer by the second cutting member with respect to the first sleeve member causes the cutting torque of the first sleeve member to decrease. Is to be increased. However, since the developer that is magnetically held and moved on the surface of the first sleeve member has already been regulated to some extent by the first cutting member, the first sleeve member The increase in the head cutting torque is significantly reduced as compared with the related art. Therefore, it is possible to achieve a reduction in the manufacturing cost and a sufficiently compact apparatus as described above.

According to the present invention, in addition to the first and second constitutions, the developer stirring and conveying means further comprises:
A second rotating spiral blade means extending along the first rotating spiral blade means on an opposite side of the second sleeve member, wherein the first rotating spiral blade means and the second rotating spiral blade means A developing device is provided in which at least the first rotating spiral blade means is rotated in a direction in which an upper half part moves away from the second sleeve member.

In the present invention, since an excessive amount of the developer is prevented from being conveyed toward the second sleeve member and the first sleeve member, the developer is restricted by the first cutting member. It is sufficiently reliably avoided that the first sleeve member is sucked and held directly on the surface of the first sleeve member without being affected. If an excessive amount of the developer is sucked and held on the surface of the first sleeve member, in the first configuration, the excess developer is held on the surface of the first sleeve member, and And the good development of the electrostatic latent image is impaired, and a sufficiently good image cannot be obtained. In the first configuration,
The amount of developer blocked by the second cutting member increases, and thus the cutting torque of the first sleeve member increases. If both the first rotating spiral blade means and the second rotating spiral blade means are rotated in a direction in which the upper half is moved away from the second sleeve member, the above-mentioned effect becomes more remarkable. .

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a developing device according to a preferred embodiment of the present invention.

FIG. 1 shows a preferred embodiment of a developing device constructed according to the present invention, together with a part of a rotary drum 2 constituting an image bearing member. The rotating drum 2 on which a suitable electrostatic photoreceptor is disposed on the peripheral surface is rotated in the direction indicated by the arrow 4 to pass through the developing area 6. The developing area 6 extends in the vertical direction in the direction of movement of the surface of the rotating drum 2 (therefore, the direction of movement of the image bearing member), and the peripheral surface of the rotating drum 2 extends from above to below in the developing area. 6 can be moved. On the upstream side of the developing area 6, an electrostatic latent image is formed on the peripheral surface of the rotating drum 2 by an appropriate method known per se. In the developing zone 6, the electrostatic latent image on the peripheral surface of the rotary drum 2 is developed into a toner image by a developing device generally designated by reference numeral 8 according to the present invention. The toner image is transferred to a transfer member such as plain paper on the downstream side of the development area 6 and fixed thereon, so that a copy or printed matter is obtained.

Referring to FIG. 2 together with FIG. 1, the developing device 8 includes a developing housing 10. The synthetic resin developing housing 10 includes a front end wall 18 together with a bottom wall 12 and a rear wall 16 extending substantially vertically upward from a rear edge of the bottom wall 12.
And a rear end wall 20. Further, the developing housing 1
An upper wall 22 covering the upper surface of the “0” is also provided.

At the forefront (the leftmost part in FIG. 1 and the uppermost part in FIG. 2) of the developing housing 10, a first developer applying means 24 and a lower part of the first developer applying means 24 are disposed. Second developer applying means 26 is provided. The first developer applying unit 24 includes a first sleeve member 28 extending substantially horizontally in a width direction (a direction perpendicular to the paper surface in FIG. 1 and a horizontal direction in FIG. 2). And the first magnet means 30 disposed therein. A first sleeve member 28, which can be formed from aluminum or the like, is rotatably mounted,
The first magnet means 30 comprises a stationary permanent magnet fixed at a predetermined position. The stationary permanent magnet extending within the first sleeve member 28 has a circular cross-sectional shape. On the peripheral surface of the stationary permanent magnet, as clearly shown in FIG.
S pole, N pole, S pole,
An S pole and an N pole are formed.

As shown in FIG. 2, the rotating shaft 36 to which the first sleeve member 28 is fixed is projected rearward through the rear end wall 20 of the developing housing 10. An input gear (not shown) is fixed to the protruding end of the rotating shaft 36, and the input gear is a rotary drive source (not shown) which may be an electric motor via a suitable transmission gear (not shown). ). Thus, the first sleeve member 28 is driven to rotate in the direction indicated by the arrow 38 (FIG. 1).

Similarly to the first developer applying means 24, the second developer applying means 26 includes a second sleeve member 40 extending substantially horizontally in the width direction, and a second sleeve member 40.
And the second magnet means 42 disposed therein. A second sleeve member 40, which can be made of aluminum or the like, is rotatably mounted, and the second magnet means 42 is composed of a stationary permanent magnet fixed at a predetermined position. The cross-sectional shape of the stationary permanent magnet extending inside the second sleeve member 40 is not circular, but has a fan-shaped missing portion 43 on the lower side in FIG. As clearly shown in FIG. 1, an N pole, an S pole, an N pole, and an N pole are sequentially formed on the peripheral surface of the stationary permanent magnet from a position immediately upstream of the developing zone 6. Due to the presence of the missing portion 43, the magnetic attraction force for sucking the developer on the surface of the second sleeve member 40 is substantially at the lower side of the second sleeve member 40 in FIG. There is a developer absent area 44 that is absent or if present at all.

As shown in FIG. 2, the rotating shaft 46 to which the second sleeve member 40 is fixed is connected to the developing housing 1.
0 and protrudes rearward through the rear end wall 20.
An input gear (not shown) is provided at the protruding end of the rotating shaft 46.
And the input gear is connected to an input gear (not shown) fixed to the rotating shaft 36 of the first developer applying unit 24. As a result, the second sleeve member 40 is driven to rotate in the direction indicated by the arrow 48 (FIG. 1).

Behind the second developer applying means 26, upstream partition means 50 and downstream partition means are provided at predetermined intervals in the front-rear direction (the left-right direction in FIG. 1 and the vertical direction in FIG. 2). 52 are provided. The upstream partition means 50 is connected to the bottom wall 12 of the developing housing 8.
Upright wall 54 projecting substantially vertically upward from the
And 56. Similarly, the downstream bulkhead means 52 is also defined by upright walls 58 and 60 projecting substantially vertically upward from the bottom wall 12 of the developer housing 8. As shown in FIG.
6, 58 and 60 have concave arc shapes on both side surfaces at the lower end. As shown in FIG. 2, the upright walls 54 and 56 do not exist in the center portion in the width direction (the direction perpendicular to the paper surface in FIG. 1 and the left and right direction in FIG. 2) and both ends in the width direction. Developer transfer ports 62, 64, and 66 are provided at the center in the direction and at both ends in the width direction, respectively. Similarly, the upright walls 58 and 60 are not present at the widthwise center portion and at both widthwise ends, but are also provided at the widthwise center portion and at both widthwise end portions of the downstream partition wall means 52, respectively. Are arranged.

A developer agitating / conveying means 74 is also provided in the developing housing 10. Developer stirring and conveying means 74
The upstream agitating / conveying means 76 disposed on the upstream side (that is, the rear side) of the upstream bulkhead means 50, the upstream bulkhead means 5
0 and the downstream partitioning means 52, and a downstream stirring and transporting means 78 disposed downstream (ie, in front of) the downstream partitioning means 52. In the developing device 8 configured according to the present invention, the downstream stirring / conveying means 80 constituting the downstream portion of the developer stirring / conveying means 74 is constituted by a rotating spiral blade means (constituting a first rotating spiral blade means). Is important. In the illustrated embodiment, not only the downstream stirring / conveying means 80 but also the midstream stirring / conveying means 78 are constituted by rotating spiral blade means (constituting the second rotating spiral blade means), and the upstream stirring / conveying means 76 is also rotated. It is composed of spiral blade means.

The upstream stirring and conveying means 76 has a rotating shaft 82 rotatably mounted between both end walls 18 and 20 of the developing housing 10. A pair of spiral blades 84 and 86 are spaced apart in the axial direction,
Are formed. The spiral blade 84 and the spiral blade 86 are wound in opposite directions. The outer diameter of the spiral blade 84 and the outer diameter of the spiral blade 86 are the same. Spiral blade 84
The inner ends in the width direction of each of the spiral blades 84 and 86 are located slightly outside the developer transfer port 62 disposed at the center in the width direction of the upstream partitioning means 50.
It is preferable that each of the widthwise outer ends is located substantially corresponding to the widthwise middle of the developer transfer ports 64 and 66 provided at both widthwise ends of the upstream partition means 50.

At both ends of the rotating shaft 82, auxiliary spiral blades 88 and 90 located opposite to the spiral blades 84 and 86, respectively.
Are formed. The outer diameter of the auxiliary spiral blades 88 and 90 may be the same as the outer diameter of the spiral blades 84 and 86. The winding direction of the auxiliary spiral blades 88 and 90 extending over an angle range of approximately 360 degrees is opposite to the winding direction of the opposing spiral blades 84 and 86. The rotating shaft 82 is further formed with an inclined elliptical plate 92 at the center in the width direction. The width dimension of the inclined elliptical plate 92 is preferably substantially the same as the width dimension of the developer transfer port 62 formed at the center of the upstream partition means 50 in the width direction. The inclined elliptical plate 92 has a circular shape in a side view.
And 86 are preferably substantially the same.

The midstream stirring and conveying means 78 also has a rotating shaft 94 rotatably mounted between both end walls 18 and 20 of the developing housing 10. The rotating shaft 94 has a pair of spiral blades 96 and 98 spaced apart in the axial direction, that is, the width direction.
Are formed. The spiral blade 96 and the spiral blade 98 are wound in opposite directions. The outer diameter of the spiral blade 96 and the outer diameter of the spiral blade 98 may be the same, and may also be substantially the same as the outer diameter of the spiral blades 84 and 86 of the upstream stirring and conveying means 76 described above. The inner ends of the spiral blades 96 and 98 in the width direction are located slightly outside the developer transfer port 68 disposed at the center in the width direction of the downstream partitioning means 52, and are spirally mounted. The outer ends in the width direction of each of 96 and 98 correspond to substantially the middle in the width direction of developer transfer ports 70 and 72 disposed at both ends in the width direction of the downstream partition wall means 52 or somewhat outwardly therefrom. It is preferably located. The rotating shaft 94 is further provided with a slanted elliptical plate 10 at its center in the width direction.
0 is formed. The width dimension of the inclined elliptical plate 100 is preferably substantially the same as the width dimension of the developer transfer port 68 formed at the center of the downstream partition means 52 in the width direction. Although the inclined elliptical plate 100 has a circular shape in a side view, the diameter of the circular shape is preferably substantially the same as the outer diameter of the spiral blades 96 and 98.

Continuing with reference to FIG. 2, the downstream stirring and conveying means 80 also has a rotating shaft 102 rotatably mounted between both end walls 18 and 20 of the developing housing 10. A pair of spiral blades 104 and 106 are formed on the rotating shaft 102 at intervals in the axial direction, that is, in the width direction. The spiral blades 104 and the spiral blades 106 are wound in opposite directions. The outer diameter of the spiral blade 104 and the outer diameter of the spiral blade 106 are the same. 1, the outer diameters of the spiral blades 104 and 106 are somewhat smaller than the outer diameters of the spiral blades 84 and 86 of the upstream stirring and conveying means 76 and the spiral blades 96 and 98 of the midstream stirring and conveying means 78. . The widthwise interval between the spiral blade 104 and the spiral blade 106 is sufficiently small, and the widthwise inner end of each of the spiral blades 104 and 106 has a developer transfer port disposed at the center in the widthwise direction of the downstream partitioning means 52. Preferably, it is located substantially corresponding to the center of 68. It is preferable that the widthwise outer ends of the spiral blades 104 and 106 are positioned substantially corresponding to the widthwise middles of the developer transfer ports 70 and 72 provided at the widthwise ends of the downstream partitioning means 52. . Auxiliary spiral blades 108 and 110 are formed at both ends of the rotating shaft 102 so as to be opposed to the spiral blades 104 and 106, respectively. The outer diameter of the auxiliary spiral blades 108 and 110 may be the same as the outer diameter of the spiral blades 104 and 106. The winding direction of the auxiliary spiral blades 108 and 110 extending over an angle range of approximately 360 degrees is opposite to the winding direction of the opposing spiral blades 104 and 106.

The rotating shaft 82 of the upstream stirring and conveying means 76, the rotating shaft 94 of the midstream stirring and conveying means 78, and the downstream stirring and conveying means 8
Each of the 0 rotation shafts 102 extends rearward through the rear end wall 20 of the developing housing 10. Input gears (not shown) are fixed to the rear ends of these rotating shafts 82, 94 and 102, respectively, and such input gears are fixed to the rotating shaft 36 of the first developer applying unit 24. Input gear (not shown). As a result, the upstream stirring and conveying means 76 and the middle flow stirring and conveying means 78
1 and arrows 112 and 114 in FIG.
And 115 are rotationally driven. In the developing device 8 configured according to the present invention, at least the downstream stirring / conveying means 80 of the downstream stirring / conveying means 80 and the middle flow stirring / conveying means 78, preferably both of the rotation directions are:
It is important that the upper half be rotated away from the second sleeve member 40 of the second developer application means 26, as indicated by arrows 115 and 114 (the reasons for which will be described later).

Continuing the description with reference to FIG. 1, the developing device 8 is further provided with an ear cutting member 120 (constituting a first ear cutting member). The ear-cutting member 120, which can be formed from non-magnetic stainless steel, is arranged to extend in the width direction along the second developer applying unit 26. As viewed in the rotational direction 48 of the second sleeve member 40, the ear-cutting member 120 is located on the upstream side of the developing region 6 and at the closest part 1 between the second sleeve member 40 and the first sleeve member 28.
On the upstream side of the second sleeve member 40, it has a leading edge close to the surface of the second sleeve member 40. The amount of the developer sucked and held on the surface of the second sleeve member 40 is regulated by the leading edge, and an appropriate layer thickness is formed on the surface.
It is preferable that the distance G1 between the leading edge of the ear cutting member 120 and the surface of the second sleeve member 40 is about 0.8 to 1.5 mm.

In the developing device 8 as described above,
As shown in FIG. 1, a developer 124 including carrier particles and toner is stored in the developing housing 10. The developer 124 is provided on the upstream side of the upstream partition means 50,
0 and the downstream partition means 52, and are appropriately dispersed and accommodated on the downstream side of the downstream partition means 52. The first developer applying means 24 and 26 apply the developer 124 to the peripheral surface of the rotating drum 2 in the developing zone 6, but basically apply the developer 12.
4 is selectively adhered to the peripheral surface of the rotating drum 2, and the electrostatic latent image on the peripheral surface of the rotating drum 2 is developed into a toner image. Therefore, the toner in the developer 124 is consumed as the development is performed. The upper wall 22 of the developing housing 10 is provided on the upper wall 22 of the developing housing 10 in correspondence with the central portion in the width direction of the upstream stirring / conveying means 76 disposed on the upstream side of the upstream partition means 50, that is, the portion where the inclined elliptical plate 92 is disposed. When a toner supply opening (not shown) is formed and a toner supply mechanism (not shown) is operated,
Through such a toner supply opening, the developing housing 10
Is supplied with toner.

Referring to FIGS. 1 and 2, the stirring and conveying of the developer 124 by the developer stirring and conveying means 74 will be described.
The toner dropped into the developer is evenly distributed to both sides from the center in the width direction by the action of the inclined elliptical plate 92 of the upstream stirring and conveying means 76, and the developer 12 in the developing housing 10 is
4 mixed. The developer 124 existing on the upstream side of the upstream partition means 50 is conveyed from the center in the width direction to both sides in the width direction while being stirred by the action of the spiral blades 84 and 86 of the upstream stirring and conveying means 76. The developer 124 conveyed to both sides in the width direction is transferred forward through developer transfer ports 64 and 66 provided on both sides in the width direction of the upstream partition means 50, and the upstream partition means 50 and the downstream partition means 5
2 and introduced. Next, between the upstream partition means 50 and the downstream partition means 52, the developer 124 is conveyed from both sides in the width direction to the center in the width direction while being stirred by the action of the spiral blades 96 and 98 of the middle flow stirring and conveying means 78. .

At the center in the width direction of the midstream stirring and conveying means 78, a part of the developer 124 is transferred forward through the developer transfer port 68 provided at the center in the width direction of the downstream partition means 52. A developer transfer port 62 in which a part of the developer 124 is disposed at the center in the width direction of the upstream partition means 50.
Transported backward through At this time, the developer 124 conveyed from one side in the width direction is appropriately distributed to both sides in the width direction and the developer 124 conveyed from the other side in the width direction by the action of the inclined elliptical plate 100 in the middle flow stirring and conveying means 78. It is appropriately distributed on both sides in the width direction. The developer transferred forward from the developer transfer port 68 disposed at the center in the width direction of the downstream partitioning means 52 is agitated by the action of the spiral blades 104 and 106 of the downstream stirring and transporting means 80 while the center in the width direction. Is conveyed to both sides in the width direction.
The developer 124 conveyed to both sides in the width direction is transported rearward through the developer transfer ports 70 and 72 provided on both sides in the width direction of the downstream partition means 52, and is connected to the upstream partition means 50 and the downstream. It is returned to the space between the partitioning means 52 and then conveyed from the center in the width direction to both sides in the width direction while being stirred by the action of the spiral blades 96 and 98 of the midstream stirring and conveying means 78.

Continuing the description with reference to FIG. 1, on the downstream side of the downstream agitating and conveying means 80, the second sleeve member 40 of the second developer applying means 26 is rotated in the direction indicated by the arrow 48. . In the developer pumping area indicated by reference numeral 126 in FIG. 1, a part of the developer 124 conveyed to both widthwise sides while being stirred by the action of the downstream stirring and conveying means 80 is formed by the second magnet means 42. The magnetic field is pumped to the surface of the second sleeve member 40. The developer 124 pumped to the surface of the second sleeve member 40 is moved in the direction indicated by the arrow 48 accompanying the rotation of the second sleeve member 40. Hot cutting member 120
Acts on the developer 124 that is magnetically held and moved on the surface of the second sleeve member 40 to remove excess developer 124 from the second sleeve member 40 and The layer thickness of the developer 124 held on the surface is made appropriate.

As described above, the ear-cutting member 120 acts on the developer 124 which is magnetically held and moved on the surface of the second sleeve member 40, and the excess developer 124
Is removed from the second sleeve member 40 to regulate the developer 124 held on the surface of the second sleeve member 40 to an appropriate layer thickness. Accordingly, the developer 124 that is magnetically held and moved on the surface of the second sleeve member 40
The forehead is forcibly dammed except for the layer thickness portion by the ear-cutting member 120, so that a pool of the developer 124 tends to be generated on the upstream side of the ear-cutting member 120. However,
In the present invention, the downstream stirring / conveying means 80 constituted by the first rotating spiral blade means is used for the second sleeve member 4.
The developer is disposed adjacent to and extends along the second sleeve member 40 on the upstream side of the ear cutting member 120 when viewed in the rotation direction 48 of 0, and is blocked by the upstream of the ear cutting member 120. Reference numeral 124 denotes the stirring and stirring of the downstream stirring and conveying means
Due to the transport action, the fluid flows along the second sleeve member 40. That is, since the developer existing on the upstream side of the ear cutting member 120 is caused to flow along the second sleeve member 40, the ear cutting torque of the second sleeve member 40 is reduced.

The developer having the appropriate layer thickness by the ear cutting member 120 and adsorbed and held on the surface of the second sleeve member 40 is applied to the first magnet means 3 of the first developer applying means 24.
0, the second sleeve member 40
As seen in the rotational direction 48 of the first sleeve member 28, it is transferred to the surface of the first sleeve member 28 on the upstream side of the closest part 122 between the first sleeve member 28 and the second sleeve member 40. The developer 124 transferred to the surface of the first sleeve member 28 and magnetically attracted and held there by the first sleeve member 28
8 along with the rotation in the direction indicated by arrow 38, and therefore through the upstream half (upper half in FIG. 1) of development zone 6. Thus, the developing area 6
In the upstream half, the developer 124 held on the surface of the first sleeve member 28 rubs the surface of the rotating drum 2, and the developing action is applied to the electrostatic latent image formed on the surface of the rotating drum 2. Will be applied.

Next, the developer 124 that has been suction-held on the surface of the first sleeve member 28 is applied to the first magnet unit 30 of the first developer application unit 24 and the second magnet unit 30 of the second developer application unit 26. Due to the magnetic field formed by the magnet means 42 of
As viewed in the rotational direction 38 of the first sleeve member 28, the second sleeve member 40 is located upstream of the closest part 122 between the first sleeve member 28 and the second sleeve member 40.
Is transferred to the surface and is suction-held there. The developer 124 transferred to the surface of the second sleeve member 40 and magnetically held therein is indicated by an arrow 4 of the second sleeve member 40.
It is moved accompanying rotation in the direction indicated by 8 and therefore through the downstream half (lower half in FIG. 1) of the development zone 6. In this way, in the downstream half of the developing zone 6, the developer 124 held on the surface of the second sleeve member 40 rubs the peripheral surface of the rotary drum 2 and is formed on the peripheral surface of the rotary drum 2. The developing action is applied to the electrostatic latent image. The electrostatic latent image formed on the peripheral surface of the rotating drum 2 is subjected to the developing action of the first developer application unit 24 in the upstream half of the developing zone 6, and then is subjected to the second developing half in the downstream half of the developing zone 6. The toner is developed into a toner image by receiving the developing action of the developer applying unit 26.

The developer 124 held on the surface of the second sleeve member 40 of the second developer applying means 26 and passed through the developing area 6 is viewed in the rotation direction 48 of the second rotary sleeve member 40. In the developer stripping zone 44 located downstream of the developing zone 6, the magnetic attraction force is substantially absent or negligible. Due to the fact that the developer 124 being stirred and conveyed acts on the surface of the second sleeve member 40, the developer 124 is separated from the surface of the second sleeve member 40 and downward toward the downstream stirring and conveying means 80. Dropped. Then, by the action of the downstream stirring / conveying means 80 constituted by the rotary spiral blade means, the developer is mixed with the developer 124 being stirred and conveyed by the downstream stirring means 80, and is again returned to the second developer applying means in the developer pumping area 126. It is effectively agitated before being pumped to the surface of the second sleeve member 40.

The following facts should be noted in the developing device 8 described above. As can be clearly understood from FIG. 1, the downstream stirring / conveying means 80 of the developer stirring / conveying means 74.
In FIG. 1, the middle-flow agitating / conveying means 78 is rotated clockwise, that is, in a direction in which the upper half thereof moves away from the second sleeve member 40 of the second developer applying means 26. For this reason, it is possible to sufficiently and reliably avoid the developer 126 being directly sucked and held on the surface of the first sleeve member 28 without receiving the action of the ear cutting member 120. The downstream stirring / conveying means 80 and the midstream stirring / conveying means 78 are counterclockwise in FIG.
In the case where the developer 126 is rotated in the direction approaching the second sleeve member 40, the developer 126 is lifted upward by the action of the downstream stirring / conveying means 80 and the midstream stirring / conveying means 78, and from above the ear cutting member 120. There is a tendency that an excessive amount of the developer 124 flows to the surface of the first surviving member 28 and is magnetically attracted and held. When such a situation occurs, an excessive amount of the developer 124 is retained on the surface of the first sleeve member 28 and is carried to the development area 6, and good development of the electrostatic latent image is impaired. A sufficiently good image cannot be obtained.

Next, another embodiment of the developing device 8 configured according to the present invention will be described with reference to FIG.
In FIG. 3, the same parts as those in FIG.
Description is omitted. The developing device 8 shown in FIG. 3 includes an ear-cutting member 130 constituting a second ear-cutting member in addition to the ear-cutting member 120 as the first ear-cutting member. The ear cutting member 130, which can be made of non-magnetic stainless steel, is arranged to extend in the width direction (the direction perpendicular to the paper surface in FIG. 3) along the first developer applying unit 24. The ear cutting member 130 is provided in the rotation direction 3 of the first sleeve member 28.
As shown in FIG. 8, on the upstream side of the development area 6, the first sleeve member 28 has a leading edge close to the surface. The amount of the developer sucked and held on the surface of the first sleeve member 28 is regulated by the leading edge, and an appropriate layer thickness is formed on the surface.

In the developing device 8 thus configured, the gap G1 between the leading edge of the first cutting member 120, which is the first cutting member, and the surface of the second sleeve member 40.
It is important that the gap G2 is set to be larger than the gap G2 between the leading edge of the ear cutting member 130 as the second ear cutting member and the surface of the first sleeve member 28. The distance G2 between the leading edge of the above-described ear cutting member 130 and the surface of the first sleeve member 28 is set to about 0.5 to 1.0 mm. The distance G1 from the surface is preferably set to about 0.8 to 1.5 mm.

Since the developing device 8 is configured as described above, first, a relatively large gap G1 between the leading edge of the ear cutting member 120 and the surface of the second sleeve member 40 causes the second The first relatively coarse regulation of the amount of the developer adsorbed and held on the surface of the sleeve member 40 is performed. Next, for the developer having a relatively coarse layer thickness transferred from the surface of the second sleeve member 40 to the surface of the first sleeve member 28, the leading edge of the front cutting member 130 and the surface of the first sleeve member 28 The second and final regulation of the developer amount is performed on the developer sucked and held on the surface of the second sleeve member 40 by the relatively small gap G2 between. Although the cutting torque of the second sleeve member 40 is reduced for the reason described above, the action of controlling the amount of the developer by the cutting member 130 with respect to the first sleeve member 28 causes the ear of the first sleeve member 28 to be reduced. The cutting torque is about to be increased. However, since the developer which is magnetically held and moved on the surface of the first sleeve member 28 has already been regulated to some extent by the ear cutting member 120, the first sleeve member 28 The increase in the head cutting torque is significantly reduced as compared with the related art.

[0043]

In the developing device constructed in accordance with the present invention, since the cutting torque can be reduced as compared with the conventional one, the manufacturing cost can be reduced and the size can be sufficiently reduced. is there. Therefore, 2
The advantage of the developing device including the individual developer applying means can be sufficiently exhibited.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a developing device configured according to the present invention.

FIG. 2 is a plan view showing the developing device shown in FIG. 1 omitting an upper wall of a developing housing and a cutting member.

FIG. 3 is a cross-sectional view illustrating another embodiment of a developing device configured according to the present invention.

[Explanation of symbols]

2: rotating drum 6: developing area 8: developing device 24: first developer applying means 26: second developer applying means 28: first sleeve member 30: first magnet means 40: second sleeve Member 42: Second magnet means 44: Developer stripping area 74: Developer stirring and conveying means 76: Upstream stirring and conveying means 78: Midstream stirring and conveying means (second rotary spiral blade means) 80: Downstream stirring and conveying means (No. One rotating spiral blade means) 120: ear cutting member (first ear cutting member) 122: closest part of first sleeve member and second sleeve member 124: developer 126: developer pumping area 130: ear Cutting member (second ear cutting member)

 ──────────────────────────────────────────────────続 き Continuing the front page (72) Akihiko Ichiba, 1-2-2, Tamazo, Chuo-ku, Osaka-shi Mita Industries Co., Ltd. (72) Shinji Kikuta 1-2-28, Tamazo, Chuo-ku, Osaka-shi Mita (72) Inventor Kazuhito Takaoka 1-2-28 Tamazo, Chuo-ku, Osaka City Inside Mita Kogyo Co., Ltd.

Claims (3)

[Claims] An electrostatic latent image formed on an image bearing member moved through a developing area is applied to a toner image by applying a developer comprising carrier particles and toner on the image bearing member in the developing area. A first developer applying means including a first sleeve member driven in rotation and a first magnet means disposed in the first sleeve member; and a rotation device driven in rotation. A second developer applying unit including a second sleeve member and a second magnet unit disposed in the second sleeve member; and a developer stirring / transporting unit. The carrier member is moved downward, the second sleeve member is disposed below the first sleeve member, and the first sleeve member and the second sleeve member have respective surfaces that are in the development zone. In the transfer of the image bearing member And the developer is magnetically attracted and held on the surface of the second sleeve member, and then the developer sucked and held on the surface of the second sleeve member is moved to the second sleeve member. Transferring to the surface of the first sleeve member upstream of the development area and upstream of the closest part between the second sleeve member and the first sleeve member in the rotational direction of the sleeve member The developer applied magnetically on the image bearing member in the development zone and then continued to be attracted and held on the surface of the first sleeve member by the surface of the second sleeve member Transferred to the developing device and applied to the image bearing member in the developing area, the developing device being located upstream of the developing area and in the second direction when viewed in the rotational direction of the second sleeve member. Sleeve member and the first sleeve portion A first edge that is close to the surface of the second sleeve member and that regulates the amount of developer sucked and held on the surface of the second sleeve member, A developer cutting and conveying means, wherein the developer stirring and conveying means is adjacent to and along the second sleeve member at an upstream side of the first cutting member when viewed in the rotational direction of the second sleeve member. Extending first rotating spiral blade means, the first rotating spiral blade means comprising:
A developing device characterized in that the agitating / transporting action causes the developer dammed upstream of the first cutting member to flow along the second sleeve member. 2. A surface of the first sleeve member having a leading edge close to a surface of the first sleeve member on an upstream side of the developing area when viewed in a rotation direction of the first sleeve member. A second cutting member that regulates the amount of developer sucked and held by the first cutting member, and a gap between the leading edge of the first cutting member and the surface of the second sleeve member is formed by the second cutting member. 2. The developing device according to claim 1, wherein the gap is set to be larger than a gap between the leading edge of the cutting member and the surface of the first sleeve member. 3. 3. The developer agitating and conveying means includes a second rotating spiral blade means extending along the first rotating spiral blade means on an opposite side of the second sleeve member, wherein the first rotating spiral blade means comprises a first rotating spiral blade means. The first rotating spiral blade means of at least the first rotating spiral blade means of the spiral blade means and the second rotating spiral blade means, the upper half of which is rotated in a direction away from the second sleeve member. 3. The developing device according to 2.