JPH05204235A - Developing device - Google Patents

Abstract

PURPOSE:To provide a developing device in which the defect of image quality caused in the case that a foreign matter is mixed in toner carried to a developing area is prevented and an excellent image is obtained as a developing device where toner cloud is formed in a developing area in which an electrostatic latent image holding body and a toner carrier are opposed and the toner is stuck to an electrostatic latent image on the electrostatic latent image holding body so as to visualize the electrostatic latent image. CONSTITUTION:A control electrode 3 consisting of plural wires stretched separately from the electrostatic latent image holding body 5 and the toner carrier 1 is provided at the position where the holding body 5 and the carrier 1 are opposed, and the wire has a resin layer 11 on its surface. Thus, discharge under bias voltage is prevented from being caused through the foreign matter. It is also good to provide a control electrode in which plural wires are stretched in nearly parallel with a vertical direction to the axial line of the toner carrier. Thus, the discharge under the bias voltage which occurs because the foreign matter gets entangled in the electrode 3 or abnormality in forming the toner cloud is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device which is used in an image forming apparatus such as an electrophotographic copying machine or a printer and which visualizes an electrostatic latent image due to a difference in charging potential by adhesion of toner. In regard to the developing device, a cloud of non-magnetic toner is generated to perform development.

[0002]

2. Description of the Related Art Conventionally, various types of developing devices for developing an electrostatic latent image due to a difference in charging potential to form a visible image have been proposed according to the type of developer used. Among them, as a developing device that uses a two-component developer in which a non-magnetic toner and a magnetic carrier are mixed to generate a toner cloud in a developing region to perform development, JP-A-1-304477 and JP-A-3-113474 are used. Some are disclosed in the official gazette.

FIG. 8 is a schematic diagram showing the developing device disclosed in Japanese Patent Laid-Open No. 3-113474. This developing device 1
Reference numeral 20 denotes a toner carrier 101, which faces the electrostatic latent image carrier 105 and which conveys non-magnetic toner on the surface thereof, in a housing 115 which houses a two-component developer, and is in proximity to the toner carrier 101. And a developer agitating member 113 for agitating the developer and supplying the developer to the developer carrying member 102. Have

The toner carrier 101 has a cylindrical shape,
It is supported so as to be rotatable about its axis. By rotating the toner carrier 101, a thin layer of toner formed on the surface is conveyed to a developing area facing the electrostatic latent image carrier 105. The electrostatic latent image holding member 105 is a belt-shaped photosensitive member capable of forming an electrostatic latent image due to a difference in charging potential on the surface thereof by irradiation of image light after being uniformly charged. Body 10
In the gap between the toner carrier 5 and the toner carrier 101, the toner carrier 1
A control electrode 111, in which a plurality of wires are stretched substantially parallel to each other in the axial direction of 01, is arranged in the vicinity of the toner carrier 101 at a distance. The developer carrying member 102 has a plurality of magnetic poles arranged at fixed positions inside, and can form a magnetic brush on the surface of which magnetic carriers accompanied by non-magnetic toner are connected in a spike shape.

In such a developing device, the magnetic brush of the developer formed on the developer carrying member 102 is conveyed by the rotation of the surface of the developer carrying member and the toner carrying member 101.
Rubbed against the surface of. An electrostatic field is formed between the developer carrier 102 and the toner carrier 101 by the DC power supplies 106 and 107, and the toner attached to the magnetic carrier is transferred to the surface of the toner carrier 101, and Form a thin layer. On the other hand, the magnetic carrier remains magnetically adsorbed on the developer carrier. The thin layer of toner formed on the toner carrier 101 is conveyed to the developing area, and the alternating electric field formed between the toner carrier 101 and the control electrode 111 causes the toner to cloud and adhere to the electrostatic latent image. Development is performed.

Such a developing device can be mainly used in a multicolor image forming apparatus using a plurality of developing devices containing toners of different colors. In particular, image formation of a system in which the electrostatic latent image carrier is rotated once to repeat the charging, exposing, and developing steps a plurality of times to form toner images of multiple colors on the electrostatic latent image carrier. In the apparatus, there is an advantage that the toner layer and the electrostatic latent image carrier can be developed without contacting each other without disturbing the toner image formed in the previous step.

[0007]

However, in the developing device as described above, the control electrode 111 made of a wire is arranged in the axial direction of the toner carrying member 101 in the vicinity of the toner carrying member 101, and therefore, as shown in FIG. As shown in FIG. 3, when a foreign substance such as a magnetic carrier or a fragment of a member used is mixed in the toner layer on the toner carrier 101, the foreign substance C is clogged in the gap between the control electrode 111 and the developing area. May stay. When the foreign matter C is conductive, a bias voltage applied to the control electrode 111 is discharged to the electrostatic latent image holder 105 via the foreign matter C, so-called a leak of a bias voltage occurs, which disturbs the electrostatic latent image. There is a problem that the image quality is deteriorated and the surface of the electrostatic latent image carrier is damaged when the discharge amount is large. Further, the leak of the bias voltage also occurs between the control electrode and the toner carrier, which may disturb the thin layer of toner or damage the surface of the toner carrier.

In addition to this, the toner layer is disturbed due to the clogging of the foreign matter, and the toner cloud is abnormally generated, and the toner adheres to the portion where there is no electrostatic latent image to form a belt-shaped toner image. There is also a problem that band-shaped defects occur. Further, when the control electrode is lifted up by a foreign substance and the electric field between the toner carrier and the control electrode is weakened, a stable toner cloud is not formed and a white spot is locally generated in the image.

The present invention has been made in view of the above problems, and an object thereof is to provide a control electrode and a toner carrier even when foreign matter is mixed in a toner layer conveyed to a developing area. It is an object of the present invention to provide a developing device capable of preventing a leak of a bias voltage between a control electrode and an electrostatic latent image holding member and obtaining a good image. Alternatively, in addition to the above, it is an object of the present invention to provide a developing device that does not cause band-shaped defects or white spots in a developed image due to the presence of foreign matter.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is arranged in close proximity to an electrostatic latent image holder on which an electrostatic latent image is formed by exposure. A toner carrier that is disposed so as to face each other and that moves non-magnetic toner on its surface to move around; and a gap is provided at a position where the electrostatic latent image carrier and the toner carrier face each other.
A control electrode for controlling the flight of the non-magnetic toner,
In a developing device for visualizing the non-magnetic toner on the toner carrier by adhering it to the electrostatic latent image, the control electrode is arranged in non-contact with the toner carrier and has a resin layer on the surface.

According to a second aspect of the present invention, it is arranged so as to closely face and oppose an electrostatic latent image holding member on which an electrostatic latent image is formed by exposure, and a non-magnetic toner is attached to the surface. And a control electrode which is disposed in a gap at a position where the electrostatic latent image carrier and the toner carrier face each other, and which controls the flying of the non-magnetic toner. In a developing device that visualizes the non-magnetic toner on the body by attaching it to the electrostatic latent image,
It is assumed that the control electrode is stretched in a direction substantially perpendicular to the axis of the toner carrier and is composed of a plurality of wires that come into contact with or come close to and away from the surface of the toner carrier.

In the developing device according to the first aspect, the resin layer having a certain degree of conductivity is used, and it is desirable that the volume resistance value is within the range of 10 ² to 10 ¹² Ω · cm. In the developing device according to the second aspect, it is desirable that the interval between the plurality of parallel wires of the control electrode is 3 mm or less. When the control electrode is arranged so as to come into contact with the toner carrier, the control electrode or the toner carrier has an insulating layer or a high electric resistance layer on the surface thereof.

[0013]

In the developing device according to the present invention, the control electrode is provided in the vicinity of the toner carrier, and the resin layer having a high electric resistance is formed on the surface of the control electrode. Even if the conductive foreign material mixed in the toner layer may enter the development area due to the rotation of the toner carrier and get caught by the control electrode, it may occur between the control electrode and the electrostatic latent image carrier or between the control electrode and the toner carrier. Bias voltage does not leak between the bodies, and deterioration of image quality is prevented. Also, without damaging the surface of the electrostatic latent image carrier or the surface of the toner carrier,
Good development is performed. Further, by setting the volume resistance value of the resin layer within the range of 10 ² to 10 ¹² Ω · cm, it is possible to prevent a decrease in electric field strength and form a stable toner cloud.

In the developing device according to the second aspect of the present invention, since the control electrode formed by stretching a plurality of wires substantially parallel to each other in the direction substantially perpendicular to the axis of the toner carrier is provided.
The flow of the toner layer on the toner carrier and the direction in which the control electrode is stretched are substantially the same, and even if foreign matter is mixed in, the toner passes through the stretched wires and is conveyed without staying in the developing area. Therefore, the leakage of the bias voltage due to the foreign matter does not occur and the deterioration of the image quality is prevented. In addition to this, it is possible to prevent the toner cloud from abnormally occurring due to the presence of foreign matter, and an image without band defects can be obtained. In addition, the occurrence of local white spots due to the floating control electrodes is also prevented. By setting the distance between the plurality of wires of the control electrode to 3 mm or less, the toner cloud required for development can be generated almost uniformly in the axial direction of the toner carrier, and a uniform density can be obtained in the width direction of the formed image. Can be maintained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a developing device which is an embodiment of the invention described in claim 1. This developing device is provided so as to face an electrostatic latent image holder 5 capable of holding an electrostatic latent image due to a difference in charging potential, and is a two-component developer including a non-magnetic toner 10 and a magnetic carrier 9. A developer carrier 2 that magnetically adsorbs a two-component developer to form a magnetic brush on the surface of the housing 15 that accommodates the developer, and the amount of the developer adsorbed on the developer carrier 2 is regulated. The developer regulating member 12, the developer carrying member 2, and the electrostatic latent image holding member 5 are arranged so as to come close to each other at different positions,
The toner carrier 1 has a cylindrical toner carrier 1 to which the non-magnetic toner 10 is attached and rotates. At the position where the toner carrier 1 and the electrostatic latent image carrier 5 face each other, the non-magnetic toner 10 is prevented from flying. A control electrode 3 for controlling is provided. A first developer stirring chamber 16 is provided in the housing 15 at a position adjacent to the developer carrying member 2, and a second developer is separated from the first developer stirring chamber 16 by a partition wall 18. A stirring chamber 17 is provided.

The first developer agitating chamber 16 and the second developer agitating chamber 17 communicate with each other at both ends in the axial direction of the toner supply member 2, and the developer is agitated and the developer is axially communicated with each other. There is provided a first screw auger 13 and a second screw auger 14 for carrying the developer. The rotation directions of these two screw augers 13 and 14 are set so as to convey the developer in mutually opposite directions, and the developer circulates in the first developer stirring chamber and the second developer stirring chamber 17. It is supposed to do.

The developer carrying member 2 has a rotatable cylindrical sleeve 21 arranged on the outer circumference of a magnet 22 supported so that its position is immovable. Two-component development is carried out on the surface of the sleeve 21. The agent can be magnetically attracted to form a magnetic brush, and the sleeve 21 can rotate to convey the developer. As the toner carrier 1, an aluminum cylinder whose surface is anodized, a cylinder made of phenolic resin, or a cylinder of aluminum having a resin layer formed on the surface thereof is used. The rotation direction is set so that both facing surfaces move in the same direction at the facing position. The toner carrier 1 and the electrostatic latent image carrier 5 are 200 to 500 μm.
Of the toner carrier 1 and the moving direction of the electrostatic latent image carrier 5 are set to be in the same direction at the facing position.
In addition, you may set so that both movement directions may become an opposite direction in the said opposing position.

Between the developer carrying member 2 and the toner carrying member 1, bias power supplies 6 and 7 are used for DC superimposed AC voltage (AC component peak-to-peak voltage is preferably 50V to 500V, DC component voltage is -100V to-). 600 V is preferable), and an oscillating electric field is generated at a position where these are close and face each other.

The control electrode 3 is composed of four thin wires stretched in the axial direction of the toner carrier 1 while maintaining a gap of about 10 to 100 μm so as not to contact the surface of the toner carrier. And these four wires are 0.5-1m
They are arranged so as to be parallel to each other at m intervals. In this embodiment, the number is four, but it can be set to an appropriate number in order to form a stable toner cloud according to the size of the toner carrier or the electrostatic latent image carrier. Further, a resin layer 11 is formed on the surface of the control electrode 3, and the resin layer 11 is provided with a certain degree of conductivity in order to prevent a decrease in electric field strength and charge-up on the wire surface. The resin layer usually has a volume resistance value of 10
² to 10 ¹² Ω · cm, preferably 10 ² to 10 ⁷ Ω ·
It is preferably in the range of 10 cm, and in this embodiment, it is set to 10 ⁴ Ω · cm. Further, as the material of the resin layer, an epoxy resin mixed with carbon black was used in the present embodiment, but other acrylic resin, melanin resin, phenol resin, urethane resin or the like can be used as the matrix resin. As the conductive filler, nickel-plated copper powder, zinc powder, iron powder, silver powder, conductive zinc oxide, tin oxide, reduced titanium oxide powder, graphite or the like may be used.

A DC voltage (-100V to -40V) is applied to the toner carrier 1 and the control electrode 3 from the bias power supplies 7 and 8.
0 V is preferable) or DC superimposed AC voltage (AC peak-to-peak voltage is preferably 200 V to 1000 V)
Is applied and an electric field is applied between the control electrode 3 and the toner carrier 1, between the control electrode 3 and the electrostatic latent image carrier 5, and between the toner carrier 1 and the electrostatic latent image carrier 5. Occurs, and these opposing portions are development areas.

In such a developing device, the non-magnetic toner 10 and the magnetic carrier 9 are conveyed in the first developer stirring chamber 16 and the second developer stirring chamber 17 and stirred so as to be uniform. .. As a result, the distribution of the non-magnetic toner 10 in the developer is maintained constant, and sufficient charge is applied to the non-magnetic toner by frictional charging between the non-magnetic toner 10 and the magnetic carrier 9. The stirred developer is supplied to the developer carrier 2 by the first screw auger 13. The developer carrier 2 magnetically adsorbs the developer to form a magnetic brush of the developer, and conveys the developer to a position facing the toner carrier 1 by rotation. A DC superposed AC voltage is applied between the toner carrier 1 and the developer carrier 2, and the charged toner is transferred to the toner carrier 1 by Coulomb force, and 0.2 m on the surface of the toner carrier.
g / cm ² to form a ~2.5mg / cm ² about a thin layer having a uniform toner. On the other hand, the magnetic carrier is the developer carrier 2
Remains magnetically adsorbed on and not transferred.

The toner layer on the toner carrier 1 is conveyed to the developing area as the toner carrier 1 rotates, passes through the position close to the control electrode 3, and the DC superimposed AC voltage applied to the control electrode 3 causes the toner layer to move. Toner cloud is generated in the developing area. The clouded toner flies in the electric field and adheres to the electrostatic latent image on the electrostatic latent image holder 5 to be developed.

At this time, in the developing area, the conductive foreign material A mixed in the toner layer may be caught by the control electrode 3 and clogged as shown in FIG. Although the conductive foreign material A may enter from the outside, it is often generated by scraping a part in the developing device. Even if such a conductive foreign substance A is mixed, the resin layer 11 is formed on the surface of the control electrode 3.
Is provided, the control electrode 3 and the electrostatic latent image holder 5 are provided.
Bias voltage does not leak between the control electrode 3 and the toner carrier 1, and a good image without deterioration of image quality can be obtained. Further, the electrostatic latent image carrier 5 and the toner carrier 1 are not damaged.

FIG. 3 is a schematic structural view showing a developing device which is an embodiment of the invention described in claim 2. In FIG. FIG. 4 is a schematic front view showing a control electrode used in this developing device, and is a view showing a state in which a wire of the control electrode 31 is stretched. This developing device is replaced with the control electrode 3 stretched in the axial direction of the toner carrier 1 in the developing device shown in FIG.
A control electrode 31 having a plurality of wires stretched in a direction substantially perpendicular to the axis of the toner carrier 1 is provided.

The control electrode 31 is stretched between two control electrode support members 32 and 33 fixed to the housing 15. The control electrode support members 32 and 33 are located above and below the toner carrier 1. And are supported so as to have edges parallel to the axis of the toner carrier. The wire having a diameter of 89 μm is used, and is supported at the edge parallel to the axis of the toner carrier 1.
They are arranged at intervals of 1 mm. In addition, each of the plurality of wires has a length of about 6 mm and is provided so as to be in contact with the peripheral surface of the toner carrier 1 via the toner layer. The bias power source 2 is used for the control electrode 31.
8 to DC superimposed AC voltage (AC component peak-to-peak voltage is preferably 200V to 1000V, DC component is -100
(V to -400V is preferable) is applied, and the toner is separated from the surface of the toner carrier 1 in the alternating electric field generated thereby, and a toner cloud is formed in the developing area. Other configurations such as the toner carrier 1, the developer carrier 2, the developer regulating member 12, the screw augers 13 and 14, the bias power sources 6 and 7 are the same as those of the developing device shown in FIG.

In such a developing device, when the foreign matter B is conveyed to the developing area as shown in FIG. 5, the direction in which the control electrode 31 is stretched is the flow of the toner layer on the toner carrier 1. The foreign matter B can pass through between the wires of the control electrode 31 because it is in the same direction. for that reason,
It is collected without staying in the developing region, and the leak of the bias voltage is prevented. Also, it is possible to prevent abnormalities in toner cloud formation due to the presence of foreign matter,
The occurrence of image quality defects is prevented.

In the developing device as shown in FIG. 1 or FIG. 3, the toner carrying member and the electrostatic latent image holding member are not in contact with each other, and the developing can be carried out without generating a strong alternating electric field between them. Therefore, it can be used in an image forming apparatus that forms toner images by superimposing them on an electrostatic latent image holder.

FIG. 6 is a schematic block diagram showing an example of a color image forming apparatus using a plurality of the developing devices of the above embodiment.
In this color image forming apparatus, the first charging device 51a, the first exposing device 52a, the first exposing device 52a, and the first exposing device 52a are arranged so that the steps of charging, exposing, and developing can be repeated a plurality of times around the electrostatic latent image carrier 5.
Developing device 53a, second charger 51b, second exposure device 52b
-The second developing device 53b and four sets of chargers, exposing devices, and developing devices are arranged in this order. The four developing devices respectively use black, red, green and blue toners. Around the electrostatic latent image holding member 5, a transfer charger 54, a peeling charger 55, and a cleaning device 5 are provided downstream of a position where four chargers, an exposure device, and a developing device are arranged.
6 are arranged. A paper tray 6 is provided between the transfer charger 54 and the peeling charger 55 and the electrostatic latent image holder 5.
Paper is carried in from 0 through the paper carry-in path 57, and after the toner image is transferred onto the paper, it is conveyed to the fixing device 59 through the paper carry-out path 58.

FIG. 7 is a diagram showing the transition of the charging potential on the surface of the electrostatic latent image holding member 5 when the color image forming apparatus as described above is operated. In this color image forming apparatus, the electrostatic latent image carrier 5 is charged to about -400 V by the first charger 51a as the electrostatic latent image carrier 5 is rotated [Fig. 7].
(A)], the image portion is about −10 by the first exposure device 52a.
It is exposed to 0 V [FIG. 7 (b)] and reverse-developed by the first developing device 53 a using black toner [FIG.
(C)]. Next, the electrostatic latent image carrier 5 is charged to about −500V by the second charger 51b [FIG. 7 (d)], and the image portion is exposed to about −100V by the second exposure unit 52b [FIG. 7 (e). )], Second developing device 53 using red toner
Reverse development is carried out by b [FIG. 7 (f)]. Then the third
The electrostatic latent image holder 5 is about -550V by the charger 51c.
7 (g), the image portion is exposed to about -140 V by the third exposing device 52 c [FIG. 7 (h)], and reverse development is performed by the third developing device 53 c using green toner [FIG. 7 (i)]. Further, the electrostatic latent image holder 5 is charged to about -600 V by the fourth charger 51d [Fig.
(J)], the image portion is about −18 by the fourth exposure unit 52d.
It is exposed to 0 V [FIG. 7 (k)] and is reverse-developed by the fourth developing device 53d having blue toner [FIG.
(L)]. Depending on the performance of the charger, the potential of the portion exposed in the previous step may be lowered, and in order to make the potential of the electrostatic latent image carrier 5 uniform by recharging, it is higher than the charged potential in the previous step. There is a need to. Therefore, the recharging potential of the electrostatic latent image holding member 5 is increased as the charging, exposing and developing steps are repeated. The four-color toner images formed on the electrostatic latent image holder through these steps are transferred onto the paper by the transfer charger 54, and then fixed by the fixing device 59 to form a color image. .

Such an image forming apparatus uses the developing device of the embodiment shown in FIG. 1 or the developing device of the embodiment shown in FIG. 3 to obtain a toner image already developed on the electrostatic latent image carrier. Even if there is, the toner images can be developed without being disturbed, and the formed four-color toner image can be obtained as a clear color image in which toners are not mixed. 40000 color image formation
As a result of the test continuously performed for about one sheet, the occurrence of image defects due to the clogging of foreign matter as in the conventional developing device was not recognized. In each of the above examples, a two-component developer is used, and only the toner is transferred from the developer carrier to the toner carrier to form a toner layer on the toner carrier, which has been conventionally proposed. The same effect can be obtained by applying the invention according to claim 1 or the invention according to claim 2 to the non-magnetic one-component developing device.

[0031]

As described above, in the developing device according to the first aspect of the invention, since the control electrode having the resin layer formed on the surface thereof is provided in the vicinity of the toner carrier, the toner layer is formed on the toner layer. Even if conductive foreign matter is mixed and conveyed to the development area, the bias voltage does not leak, image quality is prevented from deteriorating, and the surface of the electrostatic latent image holder or toner carrier is damaged. In addition, a good image can be obtained. According to the second aspect of the present invention, since the control electrode formed by stretching a plurality of wires substantially parallel to each other is provided in the direction substantially perpendicular to the axis of the toner carrier, the toner layer conveyed to the developing area. Even if a foreign substance is mixed in, the wire can pass between the stretched wires, and the leak of the bias voltage can be prevented. In addition to this, the occurrence of band-shaped defects and white spots in the image due to clogging of foreign matter is prevented, and a good image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a developing device which is an embodiment of the invention described in claim 1. FIG.

FIG. 2 is an enlarged view showing a state when foreign matter is conveyed to a developing area in the developing device of the embodiment.

FIG. 3 is a schematic configuration diagram showing a developing device which is an embodiment of the invention described in claim 2.

4 is a schematic front view of a control electrode used in the developing device shown in FIG.

FIG. 5 is a diagram showing a state when foreign matter is conveyed to a developing area in the developing device shown in FIG. 3;

6 is a schematic configuration diagram showing an example of a color image forming apparatus using a plurality of the developing devices shown in FIG. 1 or FIG.

7 is a diagram showing changes in the potential on the surface of the electrostatic latent image carrier in the image forming apparatus shown in FIG.

FIG. 8 is a schematic configuration diagram showing a conventional developing device.

FIG. 9 is a diagram showing a state in which foreign matter is conveyed to a developing area in the conventional developing device.

[Explanation of symbols]

 1 toner carrier 2 developer carrier 3 control electrode 5 electrostatic latent image carrier 6, 7, 8 bias power supply 9 magnetic carrier 10 non-magnetic toner 11 resin layer 12 developer regulating member 13 first screw auger 14 second Screw auger 15 Housing 16 First developer stirring chamber 17 Second developer stirring chamber 18 Partition wall 28 Bias power source 31 Control electrode 32, 33 Control electrode support member A, B, C Foreign matter

Claims (2)

[Claims] 1. A toner carrier, which is disposed so as to closely face and oppose an electrostatic latent image holding member on which an electrostatic latent image is formed by exposure, and which non-magnetic toner adheres to the surface to move around. And a control electrode disposed in a gap between the electrostatic latent image holding member and the toner carrying member facing each other for controlling the flight of the non-magnetic toner. In a developing device that visualizes an electrostatic latent image by attaching the control electrode to the toner carrier in a non-contact manner,
A developing device having a resin layer on its surface. 2. A toner carrier which is disposed so as to closely face and oppose an electrostatic latent image holding member on which an electrostatic latent image is formed by exposure, and which non-magnetic toner adheres to the surface and moves in a circular manner. And a control electrode disposed in a gap between the electrostatic latent image holding member and the toner carrying member facing each other for controlling the flight of the non-magnetic toner. In a developing device for visualizing by attaching to a latent image, the control electrode is stretched in a direction substantially perpendicular to the axis of the toner carrier, and comprises a plurality of wires that come into contact with or separate from the surface of the toner carrier. Characteristic developing device.