JP2000351230A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a good image by a simple constitution by reducing the load applied to toner. SOLUTION: The toner supported on a toner supply brush member 2 is charged by a charging member 4 to be flown by a toner flying member 5 to be sent into the toner passing slit 13 between a developing electrode 6 and a slit electrode 7. The toner sent into the toner passing slit 13 is vibrated by the AC electric field induced by the slit electrode 7 to which AC voltage is applied from a power supply 14 and fed and discharged to a toner outlet while diffused uniformly and selectively passed through each aperture part 8a by selectively applying voltage to the control electrode of an electrode substrate 8. Since an image can be formed on a transfer body 9 by this constitution, the load applied to the toner is reduced to obtain an image by a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device using a powder developer, and more particularly, to a printer, a facsimile, an image forming apparatus using an electrophotographic system or an electrostatic recording system.
The present invention relates to a developing device applicable to a developing unit of an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art As a developer (developing agent) used in an image forming apparatus such as a copying machine or a printer using an electrophotographic system or an electrostatic recording system, a coloring pigment is contained in particles. A so-called dry development method using toner is mainly used.

[0003] The reason for this is that the dry developing method is more advantageous in handling and providing a toner charging mechanism and miniaturizing the developing device than the wet developing method which has been used before. It is possible to adjust the retention of toner on the developing sleeve that carries and conveys the toner by using magnetic force, electrostatic force, or Van der Waals force, and to control image quality improvement such as reduction of so-called ground fog. There are advantages, such as that it is easy.

US Pat. No. 368 describes the above-mentioned electrostatic recording system.
No. 9935, JP-A-57-19763, JP-B-1-503221 and the like.
S &T's NIP 13: Internationala
l Conferenceon DigitalPri
nting Technologies PP740-
No. 745 discloses a system in which a plurality of openings are electrostatically controlled to form pixels so that toner can be selectively fly on recording paper.

FIGS. 20 and 21 show the principle and structure of the above-described method of selectively flying toner on recording paper to obtain an image.
This will be described with reference to FIG.

An electrode substrate 100 having control electrodes 102 provided around a plurality of openings (toner passage holes) 101 shown in FIG. 20 is used, for example, as shown in FIG. A non-contact arrangement is provided between the transfer member 110 and the transfer member 111 as a recording medium, a voltage is applied to the back electrode 112 provided on the back surface of the transfer member 111 and the toner carrier 110, and a voltage is selectively applied to each control electrode 102. By the application, the charged toner t on the toner carrier 110 can be selectively passed through each of the openings 101, and a toner image can be obtained on the transfer body 111.

In an image forming apparatus utilizing the electrophotographic method, an electrostatic latent image is formed on a photosensitive member as an image carrier, and the electrostatic latent image is developed with toner to form a toner image. Then, the toner image is transferred onto a transfer material to obtain an image.

As a method for developing an electrostatic latent image, a one-component developing method using a one-component developer consisting of only toner is generally used.
Compared to a two-component developing method using a developer composed of magnetic particles and a toner, the structure of the developing device is simpler and maintenance is easy, so that many developing devices using this one-component developing method have been proposed. ing.

Further, a developing method using a non-magnetic one-component developing method without using a magnetic toner, as disclosed in Japanese Patent Application Laid-Open No. 58-116559, has been proposed. It has been put to practical use to meet the demands.

FIG. 22 is a schematic sectional view showing an example of a developing device using a conventional non-magnetic one-component developing system.

In FIG. 1, reference numeral 120 denotes a rotatable developing sleeve as a developer carrier, which is substantially in contact with a photosensitive drum 130 as an image carrier at a developing section. A toner supply / recovery roller 121 as a developer supply / recovery member and a regulating blade 122 as a developer regulating member abut on the developing sleeve 120.

The regulating blade 122 has a support member 122a made of phosphor bronze or the like and an elastic member 122b made of urethane rubber or the like adhered to the tip side thereof, thereby forming a thin layer of toner on the surface of the developing sleeve 120. At the same time, it has an action of giving a charge to the toner.

The toner supply / recovery roller 121 has an outer peripheral surface of a core metal 121a such as SUS covered with an elastic member 121b such as urethane foam.
3 has a function of supplying the toner (not shown) stored in the surface 3 to the surface of the developing sleeve 120 and scraping the toner that has returned without contributing to the developing process from the surface of the developing sleeve 120. Reference numeral 124 denotes a toner stirring member for stirring the toner.

With such a configuration, the developing sleeve 12
A thin layer of non-magnetic toner on the photosensitive drum 13
By developing the electrostatic latent image on 0, a toner image can be obtained.

[0015]

In the above-mentioned conventional non-magnetic one-component developing method, the toner supply / recovery roller 121 is brought into contact with the developing sleeve 120, and is rotated and rubbed to supply and recover toner. I do. In addition, the charge is mainly applied to the toner,
It is performed by the contact friction when passing through.

That is, until the toner in the developing container 123 is developed on the photosensitive drum 130, the mechanical load (stress) on the toner is extremely large, and the damage of the toner is extremely large as compared with other developing methods. It is big.

Further, the toner deteriorated by such a mechanical load is transferred to the regulating blade 122 and the developing sleeve 12.
When the toner is fused to the nip portion between zero and the surface of the developing sleeve 120, a coating defect such as a streak is generated, and at the same time, an electric charge is not applied to the toner newly supplied onto the developing sleeve 120. Therefore, since the uncharged toner is transported to the developing unit, image formation defects such as fogging and unevenness may occur.

As described above, the contact one-component development using a non-magnetic toner imposes a large load on the toner and the developing device, and has a long-term durability and stability as compared with the conventional magnetic one-component developing device and the two-component developing device. The nature is extremely poor.

In addition to the above-described developing method, a so-called cloud developing method of flying toner to form a cloud and develop the image has been conventionally known. It is difficult to send a toner having good charging characteristics to an image forming unit with high density and uniformity without applying a large load to the image forming unit, and it has been difficult to put the toner to practical use.

In recent years, especially, the resolution of an image has been increased,
There has been a demand for improved image quality, and there has been a need to make the particle size of the toner smaller, for example, 5 μm or less. Further, in order to reduce power consumption, development of toner capable of fixing at lower temperature is desired, and a low-stress developing process corresponding to the low-temperature fixing toner is expected.

However, although the image is improved by reducing the particle size of the toner, the influence of the Van der Waals force with other members and the mirroring force due to the toner charge increases. For this reason, there have been many difficulties in the related art when an appropriate charge is held in the toner and the toner is conveyed and fed to the image forming unit to form a satisfactory image.

Therefore, in the present invention, the load applied to the toner is reduced, and stable supply of the toner to the image forming section and good image formation can be achieved with a simple configuration even for a toner having a small particle diameter. It is intended to provide a device.

[0023]

According to a first aspect of the present invention, there is provided a developing device, comprising: a brush-like rotatable developer carrier having an elastic surface for taking in and holding a powdery developer; A developer flying member which comes into contact with the developer holding member to fly the charged developer, and the developer carrier provided downstream of the developer flying member of the developer carrying member, and wherein A developer passage slit formed by the first electrode and the second electrode for taking in and passing the developer;
Voltage applying means for applying an AC voltage between the first electrode and the second electrode to generate an AC electric field in the developer passage slit, and provided on a developer outlet side of the developer passage slit; An image forming unit that forms a visible image using the developer that is diffused and conveyed and released by the AC electric field in the developer passage slit; and the developer passage slit facing the image forming unit. And a third electrode for electrostatically flying the developer toward the image forming unit, wherein a third gap between the developer passage slits is provided from the developer inlet side. The present invention is characterized in that the first electrode and the second electrode are arranged so as to gradually increase toward a developer outlet side.

A brush-like rotatable developer carrier having a resilient surface for taking in and holding the powdery developer, and a charged developer which comes into contact with the developer carrier are contacted with the developer carrier. A developer flying member to be made to fly, and a first electrode and a second electrode provided on the developer carrier downstream of the developer flying member, for taking in and passing the flying developer. A developer passage slit;
A first voltage applying means for applying an AC voltage between the first electrode and the second electrode to generate an AC electric field in the developer passage slit, and provided on a developer outlet side of the developer passage slit; An image forming unit that forms a visible image using the developer that is diffused and conveyed and released by the AC electric field in the developer passage slit; and the developer passage slit facing the image forming unit. A third electrode for discharging the developer electrostatically to the image forming means side, and a third electrode provided on the downstream side in the rotation direction of the developer carrying member of the image forming means. A developer collection slit formed by a fourth electrode and a fifth electrode, for allowing the developer not contributing to image formation by the image forming unit to flow and to be collected by the developer carrier; The fourth electrode A second voltage applying means for applying an AC voltage between the fifth electrodes to generate an AC electric field in the developer collecting slit, wherein a slit gap of the developer passing slit is formed from a developer inlet side. The first electrode and the second electrode are arranged so as to gradually increase toward the developer outlet side, and the slit gap of the developer collecting slit is directed from the developer inlet side to the developer outlet side. The fourth electrode and the fifth electrode are arranged so as to increase gradually.

The image forming means is an electrode substrate provided with electrodes around the plurality of openings.
By controlling the charged developer electrostatically by selectively applying a voltage to each of the electrodes, the developer is selectively passed through each of the openings, and the recording is performed so as to face the electrode substrate. The method is characterized in that a developer image is formed by flying the developer on a medium.

The image forming means is an electrostatic latent image carrier having an electrostatic latent image formed on a surface thereof, and the charged developer is transferred to the electrostatic latent image carrier on the electrostatic latent image carrier. It is characterized in that a developer image is formed by electrostatically flying on an image.

Further, a DC voltage is applied to the developer carrier, and the first voltage applying means is charged with a normal polarity with respect to the DC voltage applied to the developer holder. A DC voltage in a direction of drawing a developer into the developer passage slit is superimposed on the AC voltage and applied between the first electrode and the second electrode.

Further, the second voltage applying means superimposes a DC voltage in a direction of drawing a developer which has not contributed to image formation by the image forming means to the developer carrier, on the AC voltage, The voltage is applied between the fourth electrode and the fifth electrode.

[0029] The image forming apparatus further includes a stirring member for stirring the developer and holding the stirred developer on the developer carrier.

Further, a contact stirring member is provided on the upstream side of the stirring member in the rotation direction of the developer carrying member so as to contact the developer carrying member.

In addition, a charging member is provided on the upstream side of the developer carrier of the developer flying member in the rotation direction of the developer carrier so as to slidably contact the developer carried on the developer carrier and charge the developer. It is characterized by:

Further, the developer flying member is characterized in that the developer flying member contacts the developer carried on the developer carrier and charges the developer to fly.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

<First Embodiment> FIGS. 1 and 2 are schematic sectional views showing a developing device according to a first embodiment of the present invention.

As shown in FIGS. 1 and 2, a rotatable toner supply brush member 2 for taking in and carrying a toner t as a developer is provided in a developing container 1. Around the toner agitating member 3, the charging member 4, the toner flying member 5, the developing electrode 6 and the slit electrode 7 forming the toner passage slit 13 along the rotation direction (counterclockwise), and the toner collecting electrode 22, A contact toner stirring member 24 is provided.

An electrode substrate 8 as an image forming means is provided at the opening of the developing container 1 where the toner exit side of the toner passage slit 13 formed by the thin plate-like developing electrode 6 and the slit electrode 7 is located. I have. On the opposite side of the electrode substrate 8 from the developing electrode 6, a transfer body 9 as a recording medium is arranged at a predetermined distance as shown in FIG. A back electrode 10 to which a power supply 11 is connected is arranged on the back surface of the transfer body 9 so as to face the same.

The toner supply brush member 2 is constructed by attaching an elastic fur brush 2a as shown in FIG. 3 to the surface of a drum-shaped core 2b made of SUS or the like.
In this embodiment, a negative voltage (for example, a voltage of −200 V) is applied from the power supply 12 to the metal core 2b.

In the present embodiment, the fibers constituting the fur brush 2a are a conductive fiber (10 ² to 10 ⁸ Ω · cm) having low-resistance electric characteristics and a high-resistance insulating fiber (10 ^8). 〜１０10 ¹⁵ Ω · cm). Nylon fibers were used as the insulating fibers. The insulating fiber is not limited to nylon,
Insulating fibers may be selected in accordance with the characteristics of charging the toner. For example, a material such as rayon may be used as a material for negatively charging the toner.

On the other hand, it is desirable that the conductive fiber satisfies the above-mentioned resistance. In many cases, the conductive fiber is spun with a conductive resin such as carbon dispersed in the insulating fiber. And the conductive resin is not always exposed on the entire yarn surface. For this reason, in consideration of the contact between the toner and its portion, it is desirable to select a material (donor property) having a property of charging the toner to a negative polarity as a basic constituent material of the conductive fiber. Fiber can be used.

Further, since the fibers constituting the fur brush 2a need elasticity for forming the toner into a cloud, in the present embodiment, the fineness of both the conductive fibers and the insulating fibers is 1 to 10%. a denier / about the filament, in a state where they are混毛1-200000 / inch ²
And the pile length was set to 1 to 10 mm.

The charging member 4 is in contact with the tip of the fur brush 2a. The charging member 4 comes into sliding contact with the toner t taken in and carried in the fur brush 2a of the rotating toner supply brush member 2. The toner t is frictionally charged (negatively charged in this embodiment).

The charging member 4 is formed of a material having a surface having a donor property to the toner. This material can be optimally formed by, for example, glass coating or nylon attachment. The charging member 4 includes a toner transport guide member 15 curved along the outer circumference of the fur brush 2a.
Is provided on the inner surface. Toner transport guide member 15
Is arranged with a predetermined gap from the outer periphery of the fur brush 2a. One end of the toner conveying guide member 15 is located near the rotation range of the toner stirring member 3, and the other end thereof is in contact with the toner flying member 5. ing.

The toner flying member 5 provided on the downstream side of the charging member 4 is in contact with the tip of the fur brush 2a.
When the tip of the fur brush 2a rotating with the toner flying member 5 comes into contact and is elastically deformed, the charged toner (hereinafter, simply referred to as toner) carried thereon is beaten out to form a cloud. The toner clouded by the toner flying member 5 flies toward a toner passage slit 13 formed between the developing electrode 6 and the slit electrode 7.

The tip of the toner flying member 5 has a thickness of 10 mm.
It is formed of a thin metal plate made of SUS, phosphor bronze, or the like having a thickness of about 0 μm to 1 mm, and its tip is in contact with the fur brush 2a.

The thin plate-like developing electrode 6 and slit electrode 7
A slit 13 is formed so that a toner passage slit 13 is formed therebetween, and an AC voltage is applied to the slit electrode 7 from a power supply 14. The developing electrode 6 has a toner passage slit 13
The developing electrode 6 at this portion is opposed to the opening 8 a of the electrode substrate 8.

In this embodiment, as shown in FIG. 4, the toner passage slit 13 is larger than the gap (gap width) on the side of the toner entrance 13a of the toner passage slit 13 into which the toner t fly by the toner flying member 5 enters. The developing electrode 6 and the slit electrode 7 are arranged such that the gap (gap) on the side of the toner outlet 13b which is conveyed and discharged after passing through the inside 13 is larger. For example, the toner inlet 13
The gap (gap) on the side a is in the range of about 100 μm to 1 mm, and the gap (gap) on the side of the toner outlet 13 b is 200 μm.
In the range of about m to 2 mm, the gap between the electrodes on the toner outlet 13b side is gradually increased from the toner inlet 13a side. Further, the toner inlet 13a of the toner passage slit 13
Transfer length from the toner outlet 13b to the toner outlet 13b
It is about 5 mm.

As shown in FIG. 5, the electrode substrate 8 has a large number of independent circular openings 8a, and a control electrode 8b is provided around each opening 8a. Is connected to a power supply 25 (see FIG. 1) via the electrode pattern 8c.

The thin plate-like toner collecting electrode 22 is arranged along the inner surface of the developing container 1 on the downstream side in the rotation direction of the toner supply brush member 2 of the developing electrode 6. The downstream side of the toner collecting electrode 22 in the rotation direction of the toner supply brush 2 is gradually approaching the fur brush 2 a of the toner supply brush 2. A power supply 23 is connected to the toner collecting electrode 22. The power supply 23 supplies the toner collection electrode 22 with the power supply 1
When a voltage of, for example, −200 V is applied to the toner supply brush member 2 from −2, a voltage of about −250 to −700 V is applied.

The contact toner stirring member 24 is disposed so as to lightly contact the fur brush 2a of the toner supply brush member 2 upstream of the rotation range of the toner supply member 3 with respect to the rotation direction of the toner supply brush member 2. Have been.

Next, the operation of the above-described developing device will be described.

The rotation of the toner stirring member 3 causes the developing container 1
Is supplied to the fur brush 2a of the toner supply brush 2 to which a negative voltage (for example, a voltage of about -200 V) is applied. As the toner t, for example, it is preferable to use spherical fine particles (for example, having a diameter of 5 μm or less) formed by polymerization with a low melting point.

The toner supplied to the fur brush 2a is
The toner is supplied to the contact area with the charging member 4 along the inner surface of the toner transport guide member 15 while being carried by the fur brush 2 a by the rotation of the toner supply brush 2,
(In this embodiment, negatively charged) due to friction caused by light contact with the substrate.

The charged toner is supplied to the contact area with the toner flying member 5 along the inner surface of the toner transport guide member 15 while being held by the fur brush 2 a by the rotation of the toner supply brush member 2.

When the rotating fur brush 2a makes light contact with the tip of the toner flying member 5, the tip of the fur brush 2a is elastically deformed, and the retained toner is beaten out to form a cloud. . The clouded toner flies to the toner inlet side 13 a of the toner passage slit 13 between the developing electrode 6 and the slit electrode 7.

In consideration of the maintenance of the charge of the toner interposed on the contact surface with the fur brush 2a, the contact surface of the toner flying member 5 with the toner is also made of a resin having a donor property, such as nylon or carbon. ^May be laminated and the resistance thereof is adjusted to about 10 ⁵ Ω · cm. With such a configuration, the charging of the toner is further stabilized.

The toner t that has entered the toner passage slit 13 is vibrated by an AC electric field generated between the developing electrode 6 and the slit electrode 7 to which an AC voltage is applied from the power source 14 as shown in FIG. The toner is conveyed and discharged to the toner exit side 13b of the toner passage slit 13 while being uniformly diffused in the width direction of the toner passage slit 13 (perpendicular to the paper surface). At this time, since the gap (gap) on the toner outlet side 13b is gradually formed larger than the gap (gap) on the toner inlet side 13a, an electric field in which the toner advances in this direction is formed. As the amplitude of the vibrated toner gradually increases, the toner is more uniformly diffused and conveyed and discharged.

From the power source 14, the developing electrode 6 and the slit electrode 7
The AC voltage applied between the peaks is 300 Vp
p to 3 KVpp, frequency is 100 Hz to 10 KHz (preferably about 1 KHz).

Further, a DC voltage component in the direction of attracting toner to the toner supply brush 2 is applied from the power source 14 to the developing electrode 6 and the slit electrode 7 in a manner superimposed on the AC voltage, so that the toner passing slit 13 is applied to the toner passing slit 13. This can further promote preferential incorporation of toner having good charging characteristics (negative charging characteristics in the present embodiment). For example, the voltage applied to the toner supply brush member 2 (the voltage of about -200 V in the present embodiment) is 0 V as the DC component here, but the voltage applied to the toner supply brush 2 (-200 V) It is appropriate to set the magnitude to about + 50V to + 500V.

The toner uniformly diffused in the toner passage slit 13 is separated from the toner exit 13b of the toner passage slit 13 and the developing electrode 6 and the electrode substrate extending from the toner exit 13b of the toner passage slit 13. 8 between the openings 8a. Then, a predetermined voltage is selectively applied to each control electrode 8b (see FIG. 5) of the control electrode 8 in accordance with an image signal, and a predetermined voltage is applied to the back electrode 10, so that the toner is selectively arbitrarily selected. And adheres onto the transfer body 9 through the opening 8a, thereby forming a toner image.

As conditions for forming the toner image by the electrode substrate 8 and the back electrode 10, the applied voltage, the distance between the developing electrode 6 and the electrode substrate 8, and the distance between the electrode substrate 8 and the back electrode 10 are set as follows, for example. did.

As the image forming conditions in the present embodiment, the distance between the developing electrode 6 and the electrode substrate 8 was 400 μm, and the distance between the electrode substrate 8 and the back electrode 10 was 500 μm.
Further, a voltage of +3 KV is applied to the back electrode 10 from the power supply 11, and a voltage pulse of +300 V is applied to the arbitrary control electrode 8 b from the power supply 25 at 1 KHz as an example of an image forming frequency corresponding to an image to be formed. Thus, the toner charged to the negative polarity is transferred to the transfer body 9 through the opening 8a, while the toner is not passed through the opening 8a by applying a voltage of -100 V to each of the control electrodes 8b. Thus, an image can be formed.

The toner (recovered toner) that has not been transferred to the transfer body 9 when the image is formed on the transfer body 9 with the toner is transferred to the toner recovery electrode 2 to which the voltage is applied.
2, the fur brush 2a of the toner supply brush member 2
Fall while being drawn to the side. Then, the toner is supplied to the fur brush 2a effectively by the rotation of the toner supply brush member 2.

The toner effectively collected by the toner collecting electrode 22 and carried by the fur brush 2 a abuts on the upstream side of the rotation range of the toner stirring member 3 with respect to the rotation direction of the toner supply brush member 2. Toner stirring member 2
It is scraped off by 4.

Thus, when toner is supplied to the fur brush 2a of the toner supply brush member 2 by rotation of the toner stirring member 3, an appropriate amount of new toner can be carried. Further, the toner (recovered toner) scraped off by the contact toner stirring member 24 is stirred and mixed with new toner by the rotation of the toner stirring member 3, and is reused.

As described above, in the present embodiment, the toner is carried by the fur brush 2a of the rotating toner supply brush member 2, and the toner flying member 5 that contacts the toner lightly after being frictionally charged by the charging member 4 that contacts the toner lightly. The mechanical load on the toner is higher than the conventional method in which the toner is carried on the developing roller and charged by rubbing the toner with a strong pressing force using a blade plate etc. Since (stress) can be greatly reduced, deterioration of the toner can be prevented.

In the present embodiment, the charging device 4, the toner flying member 5, and the toner passage slit 13 for diffusing the clouded toner are provided around the toner supply brush member 2, so that the developing device can be used. It is possible to reduce the size of the toner, and to stably convey and discharge the uniformly dispersed toner from the toner passage slit 13 to the opening 8a side of the electrode substrate 8 with a simple configuration. Even better images can be obtained.

Further, in this embodiment, the gap (gap) of the toner outlet 13b of the toner passage slit 13 is made larger than the gap (gap) of the toner inlet 13a, so that the developing electrode 6 and the slit electrode 7 are formed. As the electric field generated between the toner passing slit 13a and the toner passing side 13a, a component is generated from the toner inlet side 13a toward the toner outlet side 13b.
As the vibration amplitude of the toner entering 3 gradually increases, the toner can be more uniformly diffused and conveyed and discharged to the electrode substrate 8 side satisfactorily.

Further, in the present embodiment, the operation from the recovery of the toner (recovered toner) not contributing to the image formation (development) to the loading and supply to the fur brush 2a of the toner supply brush member 2 is also performed. Is fur brush 2
Since the contact is made under light contact with a, the mechanical load (stress) on the toner can be significantly reduced, and the deterioration of the toner can be prevented.

In the first embodiment, the charging member 4
Is provided on the upstream side of the toner flying member 5, but the toner flying member 5 also serves as a charging member so that the toner flying member 5 comes into contact with the toner carried on the toner supply brush member 2 to fly and charge the toner. May be configured.

In the first embodiment, the inner surfaces of the slit electrode 7 and the developing electrode 6 forming the toner passage slit 13 are coated with a coating material such as a fluorine-based resin, so that the slit electrode 7 and the developing electrode 6 can be prevented from adhering to the toner. In the case where Teflon or the like having an acceptor property with respect to the toner is used as the coating agent, in order to prevent the toner charging characteristics from being deteriorated by the toner vibration due to the AC electric field on the inner surfaces of the slit electrode 7 and the developing electrode 6. Also, the toner passage slit 13
Is not so long in order to transport and discharge the toner to the toner exit side 13b of the toner passage slit 13.

In the first embodiment, the tip of the portion of the developing electrode 6 extending from the toner exit side 13b of the toner passage slit 13 is formed of an insulator, and the tip is formed of the toner supply brush member 2. By holding the developing electrode 6 in such a manner as to lightly contact the fur brush 2a, the toner not transferred to the transfer member 9 drops well without adhering to the developing electrode 6, and is collected by the fur brush 2a. be able to.

Second Embodiment FIG. 6 is a schematic sectional view showing a developing device according to a second embodiment of the present invention. In addition,
Members having the same functions as those of the developing device according to the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

In this embodiment, the power source 14 is connected to the developing electrode 6.
, An AC voltage is applied to ground the slit electrode 7 side. Further, as a DC component, the toner passing slit 1
As in the first embodiment, -200 V is applied to the toner supply brush member 2 so that the inside of the toner supply member 3 has a positive polarity (+) with respect to the voltage applied to the toner supply brush member 2.

In this embodiment, a rotatable drum-shaped electrostatic latent image carrier 20 is used as an image forming means.
The developing portion of the electrostatic latent image carrier 20 is passed through the toner passage slit 13
Of the toner outlet. Other configurations and operations are the same as those in the first embodiment, and a description thereof will be omitted in the present embodiment.

The electrostatic latent image carrier 20 has a photosensitive layer 20a formed on the outer peripheral surface of a drum-shaped conductive substrate 20b. The photosensitive layer 20a of the electrostatic latent image carrier 20 is charged by a charging means (not shown). Then, an electrostatic latent image is formed by image exposure according to image information from an exposure unit (not shown) so that, for example, the image portion potential becomes -150 V and the non-image portion potential becomes -700 V.

Then, an AC voltage (for example, a peak-to-peak voltage of 1.5 KVpp, a frequency of 2 K
Hz), and the conductive base 20b of the electrostatic latent image carrier 20 is applied.
For example, by applying +350 V from the power source 21 to the toner passage slit 13 in the same manner as in the first embodiment.
The negatively charged toner, which is uniformly diffused and flies from the toner outlet of the photosensitive layer 20, moves to the electrostatic latent image carrier 20 side, and
a directly adheres to the electrostatic latent image formed on the surface.
Thus, the electrostatic latent image is developed to obtain a toner image.

As described above, in the present embodiment using the electrostatic latent image carrier 20 as the image forming means, the same effect as in the first embodiment can be obtained.

Third Embodiment FIG. 7 is a schematic sectional view showing a developing device according to a third embodiment of the present invention. In addition,
Members having the same functions as those of the developing device of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

In the present embodiment, a configuration is used in which the developing electrode 6 whose electrode surface 6a is formed in an arc shape is used. Other configurations and operations are the same as those in the first embodiment, and a description thereof will be omitted in the present embodiment.

The arc-shaped electrode surface 6 a of the developing electrode 6 is arranged so as to face the opening 8 a of the electrode substrate 8. As the developing electrode 6, for example, a vertically formed metal rod, a semi-cylindrical column made of glass or plastic, and an electrode deposited on the arc-shaped surface, or a metal plate or a metal plate formed on the arc-shaped surface is used. A copper foil formed on a printed board can be used.

The slit electrode 7 is provided on the electrode surface 6 of the developing electrode 6.
The toner supply brush member 2a is disposed to face the upstream side in the rotation direction of the toner supply brush member 2, and a toner passage slit 13 is formed at this portion. The slit electrode 7 is supported on the inner surface of the developing container 1 by a support member 7a.

In the present embodiment, as shown in FIG.
The developing electrode 6 and the slit electrode 7 are arranged such that the gap (gap) of the toner outlet 13b which is conveyed and discharged through the toner passage slit 13 is larger than the gap (gap) of the developing electrode 6 and the slit electrode 7. . For example, the gap between the toner inlet 13 a of the toner passage slit 13 and the toner
The gap between the electrodes on the toner outlet 13b side is gradually increased from the toner inlet 13a side in the range of about 00 μm to 1 mm and the gap (gap) of the toner outlet 13b in the range of about 200 μm to 2 mm. Also, a toner passage slit 1
The toner transport length from the toner inlet 13a to the toner outlet 13b of No. 3 is about 50 μm to 5 mm.

As in the first embodiment, the toner entering the toner passage slit 13 is vibrated by an alternating current applied between the developing electrode 6 and the slit electrode 7 from the power source 14 as shown in FIG. Then, the toner is conveyed and discharged to the toner exit side 13b of the toner passage slit 13 while being uniformly diffused in the width direction of the toner passage slit 13 (direction perpendicular to the paper surface). At this time, since the gap (gap) of the toner outlet 13b is larger than the gap (gap) of the toner inlet 13a, the toner passage slit 1
As the electric field in the toner outlet 3, the toner outlet 13a to the toner outlet 1
As the component toward 3b is generated and the amplitude of the vibrated toner gradually increases, the toner is more uniformly diffused and conveyed and discharged favorably.

The toner uniformly diffused in the toner passage slit 13 is discharged from the toner outlet 13b of the toner passage slit 13 between the electrode surface 6a of the developing electrode 6 and the opening 8a of the electrode substrate 8. Then, a predetermined voltage is selectively applied to each control electrode 8b (see FIG. 5) of the control electrode 8 in accordance with an image signal, and a predetermined voltage is applied to the back electrode 10, so that the toner is selectively arbitrarily selected. And adheres onto the transfer body 9 through the opening 8a, thereby forming a toner image.

As described above, in the present embodiment using the developing electrode 6 in which the electrode surface 6a is formed in an arc shape, the same effect as in the first embodiment can be obtained.

Fourth Embodiment FIG. 9 is a schematic sectional view showing a developing device according to a fourth embodiment of the present invention. In addition,
Members having the same functions as those of the developing device according to the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

In this embodiment, the toner passage slit 1
3 is formed by the slit electrode 7 and the electrode 32, and the opening 8 of the electrode substrate 8 is
This is a configuration in which a wire-like developing electrode 6 is arranged so as to face the portion a. The electrode surfaces of the slit electrode 7 and the electrode 32 are formed on support members 7a and 32a, respectively. On the toner outlet side of the toner passage slit 13 of the electrode 32, a thin insulating member 33 is held so that one end side is in light contact with the fur brush 2a. Other configurations are the same as those of the third embodiment.

Also in the present embodiment, the gap (gap) on the toner outlet side where the toner is discharged becomes gradually larger than the gap (gap) on the toner inlet side where the toner of the toner passage slit 13 is taken in. Thus, the slit electrode 7 and the electrode 32 are arranged. The developing electrode 6 is grounded (earthed).

The insulating member 33 is provided with the toner passage slit 1
The toner that falls without passing through the toner supply brush 3 is again carried on the fur brush 2a of the toner supply brush 2 and collected.

As in the first embodiment, the toner that has entered the toner passage slit 13 is made more uniform by forming the AC electric field and the gap on the toner outlet side larger than the gap on the toner inlet side. It is diffused and satisfactorily released between the opening 8 a of the electrode substrate 8 and the developing electrode 6.
Then, similarly to the first embodiment, a predetermined voltage is selectively applied to each control electrode 8b of the control board 8 according to an image signal, and a predetermined voltage is applied to a back electrode (not shown). The toner selectively passes through an arbitrary opening 8a and adheres to a transfer member (not shown), so that a toner image is formed. The following operation is the same as in the first embodiment. In the present embodiment, by applying a voltage obtained by superimposing an AC voltage on a DC voltage from the power supply 23 to the toner collecting electrode 22, the toner not contributing to the development vibrates, and the toner which has not contributed to the development vibrates. It is attracted to 2a, carried and collected.

As described above, the toner passage slit 13 is formed by the slit electrode 7 and the electrode 32, and the wire-like developing electrode 6 is arranged so as to face the opening 8a of the electrode substrate 8 in this embodiment. Thus, the same effect as in the first embodiment can be obtained.

Fifth Embodiment FIGS. 10 and 11 are schematic sectional views showing a developing device according to a fifth embodiment of the present invention. Members having the same functions as those of the developing device according to the first embodiment are denoted by the same reference numerals, and overlapping description will be omitted.

In this embodiment, the developing electrode 6 extends downstream of the toner supply brush member 2 in the rotation direction of the toner supply brush member 2 and faces the toner collection electrode 22 upstream of the toner supply brush member 2 in the rotation direction. A toner collecting slit into which toner (collected toner) that has not contributed to image formation (development) of the toner conveyed and discharged from the toner passage slit 13 by the electrode substrate 8 flows between the developed electrode 6 and the toner collecting electrode 22. 28 are formed. Further, the downstream side in the rotation direction of the toner supply brush 2 of the toner collection electrode 22 is extended and gradually approaches the fur brush 2 a of the toner supply brush 2. Other configurations and operations are the same as those of the first embodiment,
The description of this embodiment is omitted.

In the present embodiment, as shown in FIG. 12, a gap (gap) on the side of the toner inlet 28a into which the toner (recovered toner) not contributing to the image formation (development) of the toner recovery slit 28 flows. The gap (gap) on the side of the toner outlet 28b which flows out through the toner collecting slit 28 gradually becomes larger than
The developing electrode 6 and the toner collecting electrode 22 are arranged. For example, the gap (gap) between the toner inlet 28a of the toner collection slit 28 and the toner outlet 28b is in a range of about 200 μm to 2 mm, and about 300 μm to 3 mm.
In the toner outlet 2 range from the toner inlet 28a side.
The gap between the electrodes 8b is gradually increased.

A voltage obtained by superimposing a DC voltage in a direction in which toner is collected on the fur brush 2 a of the toner supply brush 2 onto an AC voltage from a power supply 23 is applied to the toner collecting electrode 22. For example, from the power source 23 to the toner collecting electrode 22,
For example, −200 is supplied from the power supply 12 to the toner supply brush member 2.
When a voltage of V is applied, a DC voltage of about -250 to -700 V is applied. The value of the AC voltage applied from the power supply 23 to the toner collecting electrode 22 is the power supply 1
4 is preferably equal to or higher than the voltage value applied to the toner passage slit 13.
pp to 5KVpp.

As in the first embodiment, the toner entering the toner passage slit 13 is vibrated by an AC voltage applied between the developing electrode 6 and the slit electrode 7 from the power source 14 as shown in FIG. The toner outlet 1 of the toner passage slit 13 while being uniformly diffused in the width direction of the toner passage slit 13 (perpendicular to the paper surface).
It is conveyed and discharged favorably to the 3b side.

The toner uniformly diffused in the toner passage slit 13 flows from the toner outlet 13b of the toner passage slit 13 to the toner exit 13b of the toner passage slit 13 between the developing electrode 6 and the opening 8a of the electrode substrate 8. Released. Then, each control electrode 8b of the control electrode 8 (FIG. 5)
2), a predetermined voltage is selectively applied in accordance with an image signal, and a predetermined voltage is applied to the back electrode 10. As a result, the toner selectively passes through an arbitrary opening 8a onto the transfer member 9. Attach and a toner image is formed.

When the toner is formed on the transfer member 9 by the toner, the toner (recovered toner) that has not passed through the opening 8a of the electrode substrate 8 and has not moved to the transfer member 9 is supplied from the power source 23 to the toner recovery electrode. The toner flows into the toner inlet 28a of the toner collecting slit 28 by the DC voltage superimposed on the toner. As shown in FIG. 12, the collected toner flowing into the toner inlet 28a of the toner collecting slit 28 is vibrated by an AC electric field generated between the developing electrode 6 to which the AC voltage is applied from the power source 23 and the toner collecting electrode 22. The toner is passed through the toner collecting slit 28 smoothly without stagnation, and flows out from the toner outlet 28b.

The collected toner flowing out of the toner outlet 28b is attracted to the toner supply brush 2 by the DC voltage superimposed and applied to the toner collection electrode 22 from the power supply 23, carried on the fur brush 2a, and collected.

As described above, in this embodiment, in addition to the effects obtained in the first embodiment, the toner (recovered toner) that has not contributed to image formation (development) can be effectively removed by the toner recovery brush by the toner recovery electrode 22. It can be collected by the fur brush 2a of the member 2.

<Sixth Embodiment> FIG. 13 is a schematic sectional view showing a developing device according to a sixth embodiment of the present invention. Members having the same functions as those of the developing device according to the fifth embodiment are denoted by the same reference numerals, and overlapping description will be omitted.

In this embodiment, the power source 14 is connected to the developing electrode 6.
, An AC voltage is applied to ground the slit electrode 7 side. Further, as a DC component, the toner passing slit 1
As in the fourth embodiment, -200 V is applied from the power supply 12 to the toner supply brush member 2 so that the inside of the toner supply member 3 has a positive polarity (+) with respect to the voltage applied to the toner supply brush member 2.

In this embodiment, a rotatable drum-shaped electrostatic latent image carrier 20 is used as an image forming means.
The developing portion of the electrostatic latent image carrier 20 is passed through the toner passage slit 13
Of the toner outlet. Other configurations are the same as those of the fifth embodiment, and a description thereof will be omitted in the present embodiment.

The electrostatic latent image carrier 20 has a photosensitive layer 20a formed on the outer peripheral surface of a drum-shaped conductive base 20b, and the photosensitive layer 20a of the electrostatic latent image carrier 20 is charged by a charging means (not shown). Then, an electrostatic latent image is formed by image exposure according to image information from an exposure unit (not shown) so that, for example, the image portion potential becomes -150 V and the non-image portion potential becomes -700 V.

Then, an AC voltage (for example, a peak-to-peak voltage of 1.5 KVpp, a frequency of 2 K
Hz), and the conductive base 20b of the electrostatic latent image carrier 20 is applied.
By applying, for example, +350 V from the power source 21 to the toner passage slit 13 in the same manner as in the fifth embodiment.
The negatively charged toner, which is uniformly diffused and flies from the toner outlet of the photosensitive layer 20, moves to the electrostatic latent image carrier 20 side, and
a directly adheres to the electrostatic latent image formed on the surface.
Thus, the electrostatic latent image is developed to obtain a toner image.

The toner (recovered toner) that has not contributed to the development of the electrostatic latent image flows into the toner inlet of the toner recovery slit 28 due to the DC voltage superimposed on the toner recovery electrode 23 from the power source 23. I do. The collected toner that has flowed into the toner inlet of the toner collecting slit 28 is vibrated by an AC electric field generated between the developing electrode 6 and the toner collecting electrode 23 to which the AC voltage is applied from the power supply 23, and the toner is collected by the toner collecting slit. The toner passes smoothly without stagnation in the toner outlet 28 and flows out from the toner outlet side. The following operation is the same as in the fifth embodiment.

As described above, in the present embodiment using the electrostatic latent image carrier 20 as the image forming means, the same effect as in the fifth embodiment can be obtained.

Seventh Embodiment FIG. 14 is a schematic sectional view showing a developing device according to a seventh embodiment of the present invention. Members having the same functions as those of the developing device according to the third embodiment are denoted by the same reference numerals, and redundant description is omitted.

In the present embodiment, the configuration is such that the developing electrode 6 in which the electrode surface 6a is formed in an arc shape is used. Other configurations and operations are the same as those of the third and fifth embodiments, and a description thereof will be omitted in the present embodiment.

In the present embodiment, too, the gap (gap) at the toner outlet which is conveyed and discharged through the toner passage slit 13 is larger than the gap (gap) at the toner entrance of the toner passage slit 13. The developing electrode 6 and the slit electrode 7 are arranged so as to increase gradually.

As in the first embodiment, the toner entering the toner passage slit 13 is generated between the developing electrode 6 and the slit electrode 7 to which an AC voltage is applied from the power source 14 as shown in FIG. Vibration is given by the alternating electric field, and the toner is conveyed and discharged to the toner outlet 13b of the toner passage slit 13 while being uniformly diffused in the width direction of the toner passage slit 13 (perpendicular to the paper). At this time, the gap (gap) of the toner outlet 13b is formed to be gradually larger than the gap (gap) of the toner inlet 13a, and is more uniformly diffused and conveyed and discharged as in the above-described embodiment. You.

Then, the toner uniformly diffused in the toner passage slit 13 flows from the toner exit 13 b of the toner passage slit 13 to the electrode surface 6 a of the developing electrode 6 and the electrode substrate 8.
Is released between the openings 8a. Then, by selectively applying a predetermined voltage to each control electrode 8b (see FIG. 5) of the electrode substrate 8 in accordance with the image signal and applying a predetermined voltage to the back electrode 10, the toner is selectively arbitrarily selected. And adheres onto the transfer body 9 through the opening 8a, thereby forming a toner image.

The toner (recovered toner) that has not contributed to the image formation (development) by the electrode substrate 8 enters the toner inlet 28 a of the toner recovery slit 28 by the DC voltage superimposed on the toner recovery electrode 22. Inflow. The collected toner flowing into the toner inlet 28a of the toner collecting slit 28 is vibrated by an AC electric field generated between the electrode surface 6a of the developing electrode 6 to which the AC voltage is applied and the toner collecting electrode 22, as shown in FIG. And smoothly passes through the toner collecting slit 28 without stagnation, and flows out from the toner outlet side 28b.
The following operation is the same as in the fifth embodiment.

As described above, in the present embodiment using the developing electrode 6 in which the electrode surface 6a is formed in an arc shape, the same effect as that of the fifth embodiment can be obtained.

<Eighth Embodiment> FIG. 16 is a schematic sectional view showing a developing device according to an eighth embodiment of the present invention. Note that members having the same functions as those of the developing devices of the above-described embodiments are denoted by the same reference numerals, and overlapping descriptions will be omitted.

In the present embodiment, in the developing device shown in FIG. 16, opposing surfaces 6a and 7a of the developing electrode 6 and the slit electrode 7 forming the toner passage slit 13 are respectively provided.
b is covered with an insulating film. Other configurations and operations are the same as those of the above-described embodiments (in the present embodiment, for example, the developing device of the fifth embodiment), and a description thereof will be omitted in the present embodiment.

The present inventor evaluated the effect of covering the opposing surfaces 6a and 7b of the developing electrode 6 and the slit electrode 7 forming the toner passage slit 13 with an insulating film using the following experimental electrode slits. did.

This experimental electrode slit is shown in FIG.
As shown in (a) and (b), spacers 52 and 53 having different thicknesses are interposed between
A wedge-shaped slit 54 was formed between the two.

The electrodes 50 and 51 are respectively connected to the glass substrate 5
Transparent conductive films (ITO) 57, 58 coated on 5, 56
The surface is covered with insulating films 59 and 60. The spacer 52 (thickness 0.3 mm) side of the slit 54 is the toner inlet side, and the spacer 53 (thickness 0.6)
mm) side is the toner outlet side, and the slit is larger at the toner outlet than at the toner inlet. The slit length (toner passage length) of the slit 54 is 6 mm, and the slit forming width is 70 mm.

Then, transparent conductive films (ITO) 57, 58
In the meantime, the peak-to-peak voltage of the AC rectangular wave is 1.5 KV from the power supply 61.
An AC voltage having a pp frequency of 2 KHz is applied, and the electrophotographic toner normally used as a negative (negatively charged) toner is negatively charged by a toner contact charging device (not shown). Then, the toner is forcibly fed into the slit 54 from the toner entrance of the slit 54, and the relative value of the charge amount of the toner after discharging from the slit 54 before taking in the toner into the slit 54 and the toner discharged from the slit 54. The state of the toner was evaluated. In this evaluation, a plurality of experimental electrode slits in which the insulating films 59 and 60 were made of silicone, 6-6 nylon, polyimide, and Teflon as shown in FIG. 18 were used. As a comparative example, an experimental electrode slit without an insulating film was also formed.

As is clear from the evaluation results shown in FIG. 18, it is effective to cover the inner surface of the slit 54 with the insulating films 59 and 60, and the insulating film to be used is generally a donor material. It has been found that a material insulating film having the following properties is preferable. In particular, the silicone hard coat material has good diffusion and release of the negatively charged toner by the slit 54. Due to the AC electric field generated by the AC voltage application, the toner hardly remains in the slit 54 and is discharged from the toner outlet side. Was observed.

In this embodiment, the toner taken into the toner entrance of the toner passage slit 13 is negatively charged as in the above-described embodiments, but forms the toner passage slit 13. By coating the respective surfaces 6a and 7b of the developing electrode 6 and the slit electrode 7 with a material insulating film having a donor property, for example, a glass coat or a nylon coat, the toner has the following characteristics. Toner passage slit 13
When the toner is discharged from the toner outlet, the negative charging characteristic is uniformly increased more than when the toner is taken into the toner inlet.

That is, the toner passes through the toner passage slit 1
3, the average charge amount of the toner is increased. This phenomenon occurs because the toner oscillating by the AC electric field in the toner passage slit 13 collides with the insulating film coated on the respective surfaces 6a and 7b of the developing electrode 6 and the slit electrode 7, thereby receiving friction. It is considered that the toner is strongly affected by the contact charging characteristics between the insulating film and the toner.

Accordingly, as a further effect, since the slit on the toner outlet side of the toner passage slit 13 is larger than the slit on the toner inlet side, the charged toner is not affected by the AC voltage regardless of its charging polarity. The toner moves from the toner inlet to the toner outlet as an effect of the AC electric field due to the application. During this movement, for example, when the desired charge polarity of the toner is negative, the so-called inverted toner (the positively charged toner in this case) becomes the toner. Even if the inverted toner is discharged from the toner outlet even if it is taken into the passage slit 13, the charging characteristic can be changed in the negative direction. Further, the uncharged toner moves in the toner passage slit 13 by the vibration of the surrounding charged toner caused by the AC electric field, so that a desired charging characteristic can be obtained.

As described above, in the present embodiment, the respective surfaces 6a and 7b of the developing electrode 6 and the slit electrode 7 forming the toner passage slit 13 are covered with the insulating film, so that the toner exit from the toner passage slit 13 The discharged toner is uniformly charged to a regular polarity (negative polarity), so that it is favorably used for image formation (development).

Further, all the toners have normal polarity (negative polarity).
The toner that has not contributed to the image formation (development) by being charged is charged to the toner collecting electrode 22 to which the voltage is applied.
Of the toner supply brush member 2, and the toner can be collected and retained by the fur brush 2 a.

In the present embodiment, the surfaces 6a and 7b of the developing electrode 6 and the slit electrode 7 forming the toner passage slit 13 of the developing device described in the fifth embodiment, respectively.
Is covered with an insulating film, but the same can be applied to other embodiments.

<Embodiment 9> FIG. 19 is a schematic structural view showing an image forming apparatus provided with the developing device of the present invention.

In this image forming apparatus, for example, four developing devices 30a, 30b, 30c, and 30d having the same configuration as that of the first embodiment are vertically arranged in an apparatus main body 31. Each developing device 30a, 30b, 30c, 30d
Is similar to that of the first embodiment, and a description thereof will be omitted in the present embodiment. Each developing device 30a, 30b, 30
In c and 30d, toners as black, cyan, magenta, and yellow developers are stored, respectively.

Developing devices 30a, 30b, 30c, 30d
An endless belt-shaped transfer member 40 is provided so as to face each of the electrode substrates 8. A roller-shaped back electrode 41 is provided on the back side of the transfer member 40 that faces each of the electrode substrates 8.
a, 41b, 41c and 41d are arranged respectively. The belt-shaped transfer member 40 is driven by driven rollers 42a and 42
b, 42c, drive roller 42d, and heating body 4 in sliding contact
3 and is rotated in the direction of the arrow by the rotation of the drive roller 42d. The transfer fixing unit T in which the heating member 43 is disposed is provided with a pressure roller 44 that is rotatable via the transfer member 40. A transfer material P such as a sheet is fed to the transfer fixing unit T by a feed roller 45.

Next, an image forming operation by the above-described image forming apparatus will be described.

First, the black toner image is transferred onto the transfer body 40 by selectively passing the black toner through the respective openings 8a of the control substrate 8 according to the black image information by the developing device 30a. The operation of forming the black toner image by the developing device 30a is performed as described in the first embodiment.

Then, the black toner image transferred onto the transfer member 40 by the rotation of the drive roller 42d moves to the position of the developing device 30b, and selectively controls the control substrate 8 according to the cyan image information as described above. After passing through each opening 8a, the cyan toner image is superimposed and transferred on the black toner image of the transfer body 40.

Thereafter, similarly, a magenta toner image is superimposed on the toner image by the developing device 30c and a yellow toner image is superposed and transferred on the toner image by the developing device 30d to form a full-color toner image.

Then, at a predetermined timing, the paper feed roller 4
5, the transfer material P such as paper is conveyed to the transfer and fixing unit T, and the full-color toner image formed on the transfer body 40 is transferred to the transfer and fixing unit T by the heat of the heating element 43 and the pressure roller 44.
Is transferred and fixed on the transfer material P at the same time.
The transfer material P on which the full-color toner image has been transferred and fixed at the same time is discharged outside by the discharge roller 46, and the full-color image formation is completed.

As described above, in the image forming apparatus according to the present embodiment, by using the developing device described above, the size of the entire device can be reduced, and the mechanical load (stress) on the toner can be reduced.
, And good image formation can be performed with a simple configuration.

[0137]

As described above, according to the present invention, a developer flying member and a developer passage slit for diffusing the flying developer by an AC electric field are provided around the brush-shaped developer carrier, The configuration in which the developer exit side of the developer passage slit is gradually larger than the developer entrance side allows the development device to be downsized, and the developer passage slit allows the developer to be more uniformly diffused with a simple configuration. From the paper to the image forming means side to obtain a good image.

Further, since the developer outlet side of the developer collecting slit for collecting the developer not contributing to the image formation (development) is made gradually larger than the developer inlet side, the developer taken into the developer collecting slit is formed. Since the developer can be diffused and released by the AC electric field, the developer can be favorably recovered.

Further, the developer is carried by a brush-like developer carrier, and the developer is made to fly by a developer flying member that comes into contact with the developer carrier to form a cloud, thereby forming an image (development).
Then, the developer not contributing to the image formation (development) is carried and collected by the brush-like developer carrier, whereby
Since the mechanical load (stress) on the toner can be significantly reduced, the deterioration of the toner can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a schematic sectional view showing a developing device according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a part of a fur brush of the toner supply brush member.

FIG. 4 is a schematic sectional view showing a toner passage slit and an electrode substrate of the developing device according to the first embodiment of the present invention.

FIG. 5 is a plan view illustrating an example of an electrode substrate.

FIG. 6 is a schematic sectional view showing a developing device according to a second embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a developing device according to a third embodiment of the present invention.

FIG. 8 is a schematic sectional view showing a toner passage slit and an electrode substrate of a developing device according to a third embodiment of the present invention.

FIG. 9 is a schematic sectional view showing a developing device according to a fourth embodiment of the present invention.

FIG. 10 is a schematic sectional view showing a developing device according to a fifth embodiment of the present invention.

FIG. 11 is a schematic sectional view showing a developing device according to a fifth embodiment of the present invention.

FIG. 12 is a schematic sectional view showing a toner passage slit and an electrode substrate of a developing device according to a fifth embodiment of the present invention.

FIG. 13 is a schematic sectional view showing a developing device according to a sixth embodiment of the present invention.

FIG. 14 is a schematic sectional view showing a developing device according to a seventh embodiment of the present invention.

FIG. 15 is a schematic sectional view showing a toner passage slit and an electrode substrate of a developing device according to a seventh embodiment of the present invention.

FIG. 16 is a schematic sectional view showing a developing device according to an eighth embodiment of the present invention.

FIG. 17A is a side view showing an experimental electrode slit used for evaluating the effect of the developing device according to the eighth embodiment;
(B) is a plan view showing an experimental electrode slit used for evaluating the effect of the developing device in the eighth embodiment.

FIG. 18 is a diagram showing an evaluation result by an experimental electrode slit according to the eighth embodiment.

FIG. 19 is a schematic sectional view showing an image forming apparatus according to Embodiment 9 of the present invention.

FIG. 20 is a plan view illustrating an example of an electrode substrate.

FIG. 21 is a schematic configuration diagram illustrating an example of a developing device in a conventional example.

FIG. 22 is a schematic configuration diagram illustrating an example of a developing device in a conventional example.

[Explanation of symbols]

 Reference Signs List 1 developing container 2 toner supply brush member (developer holding member) 2a fur brush 2b cored bar 3 toner stirring member (stirring member) 4 charging member 5 toner flying member (developer flying member) 6 developing electrode (first electrode, Third electrode 7 Slit electrode (second electrode) 8 Electrode substrate (image forming means) 8a Opening 8b Control electrode (electrode) 9 Transfer member (recording medium) 10 Back electrode 13 Toner passage slit (developer passage slit) 14) Power supply (voltage applying means, first voltage applying means) 20 Electrostatic latent image carrier 20a Photosensitive layer 20b Conductive substrate 22 Toner collecting electrode (fourth electrode) 23 Power supply (second voltage applying means) 24 Contact toner stirring member (contact stirring member) 26 Toner collision member (developer collision member) 28 Toner recovery slit (developer recovery slit) 30a, 30b, 30c 30d a developing device 32 electrode 33 insulating member 40 transcript 43 heater

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Yamaji 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Osamu Iwasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Takeshi Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) 2C162 AE25 AE31 AE74 AE84 AJ25 AJ26 CA03 CA12 CA24 2H029 DB04 2H073 BA03 BA13 BA15 CA13 CA14 2H077 AB03 AD02 AD05 AD23 AE03

Claims (10)

[Claims] 1. A brush-like rotatable developer carrier having a resilient surface for taking in and holding a powdery developer, and contacting the developer carrier to fly the charged developer. A developer flying member that is provided downstream of the developer flying member of the developer carrying member, and is formed by a first electrode and a second electrode that receive and pass the flying developer. A developer passage slit; a voltage application unit for applying an AC voltage between the first electrode and the second electrode to generate an AC electric field in the developer passage slit; and a developer outlet of the developer passage slit. Provided on the side, an image forming unit that forms a visible image using the developer that is diffused and conveyed and released by the AC electric field in the developer passage slit, and faces the image forming unit. The developer passage A third electrode disposed on the developer outlet side of the slit and configured to electrostatically fly the developer toward the image forming unit; and a third gap between the developer passage slit and the developer inlet side. Wherein the first electrode and the second electrode are arranged such that the first electrode and the second electrode gradually increase in size toward the developer outlet side. 2. A brush-like rotatable developer carrier having a resilient surface for taking in and holding a powdery developer, and contacting the developer carrier with the charged developer. A developer flying member to be made to fly, and a first electrode and a second electrode provided at the downstream side of the developer flying member of the developer carrier to take in and pass the flying developer. A developer passage slit; first voltage applying means for applying an AC voltage between the first electrode and the second electrode to generate an AC electric field in the developer passage slit; and the developer passage slit. An image forming unit that is provided on the developer outlet side of the developer and forms a visible image using the developer that is diffused by the AC electric field and conveyed and discharged in the developer passage slit; So that A third electrode disposed on the developer outlet side of the image agent passage slit for causing the developer to electrostatically fly toward the image forming unit; and a rotation direction of the developer carrier of the image forming unit. A developing device formed on the downstream side, the developing device being formed by the fourth electrode and the fifth electrode for allowing a developer not contributing to image formation by the image forming means to flow therein and to be recovered by the developer carrier; A developer collection slit; and a second voltage applying unit configured to apply an AC voltage between the fourth electrode and the fifth electrode to generate an AC electric field in the developer collection slit. The first electrode and the second electrode are arranged so that the slit gap of the passage slit gradually increases from the developer inlet side to the developer outlet side, and the slit gap of the developer collection slit is From the developer inlet side Agent so that gradually increases toward the outlet side, and arranging the fifth electrode and the fourth electrode, that developing device is characterized in. 3. The image forming means is an electrode substrate provided with electrodes around a plurality of formed openings, and the charged developer is electrostatically applied by selectively applying a voltage to each of the electrodes. The developer is selectively passed through each of the openings to form a developer image by causing the developer to fly onto a recording medium disposed to face the electrode substrate. The developing device according to claim 1 or 2, wherein 4. The image forming means is an electrostatic latent image carrier having a surface on which an electrostatic latent image is formed, and the charged developer is transferred to the electrostatic latent image carrier on the electrostatic latent image carrier. The developing device according to claim 1, wherein a developer image is formed by electrostatically flying the image. 5. A DC voltage is applied to the developer carrier,
The first voltage applying unit is configured to generate a DC voltage in a direction of drawing the developer charged to a regular polarity into the developer passage slit with respect to the DC voltage applied to the developer holding member. 5. The developing device according to claim 1, wherein the developing device is superimposed on an AC voltage and is applied between the first electrode and the second electrode. 6. The second voltage applying unit superimposes a DC voltage in a direction of drawing a developer that has not contributed to image formation in the image forming unit toward the developer carrier, on the AC voltage, The developing device according to claim 2, wherein the voltage is applied between the fourth electrode and the fifth electrode. 7. The stirring device according to claim 1, further comprising a stirring member for stirring the developer and holding the stirred developer on the developer carrier. The developing device as described in the above. 8. The contact stirring member provided on the upstream side of the stirring member in the rotation direction of the developer carrying member so as to contact the developer carrying member. Developing device. 9. A charging member for slidingly contacting the developer carried on the developer carrying member and charging the developer is provided upstream of the developer flying member in the rotation direction of the developer carrying member. The developing device according to claim 1, 2, 3, 4, 5, 6, 7, or 8. 10. The developer flying member according to claim 1, wherein the developer flying member contacts the developer carried on the developer carrier to charge and fly the developer. 9. The developing device according to 4, 5, 6, 7, or 8.