JP2001051567A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide a low-stress coat capable of coping with low-temperature fixing toner by significantly reducing the load on non-magnetic toner during development when forming a color image by development using a plurality of developing devices. And a toner layer containing no reversal toner or the like on the developing roller, and a cleaner-less image forming process can be realized. A developing device installed in each of a plurality of image forming units of an image forming apparatus includes a developing container, a non-magnetic toner, a developing roller, a toner supply brush, a toner flow control member. 5, a toner regulating blade 7, a toner collecting roller 8, a scraper 9, and a toner stirring member 10. A predetermined voltage is applied to the developing roller 1 by a power supply 2, a power supply 6 to the toner supply brush 4, and a power supply 11 to the collection roller 8. The collection roller 8 electrostatically removes the residual toner on the developing roller 1 and the residual toner on the photosensitive drum 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an image forming process such as an electrophotographic system or an electrostatic recording system, and more particularly to a method for transferring a visible image formed on a plurality of image carriers by multiple transfer. The present invention relates to an image forming apparatus for obtaining a multicolor image. The image forming apparatus of the present invention can be embodied not only in a copying apparatus but also in various printers and facsimile machines.

[0002]

2. Description of the Related Art With the spread of digital color copying machines, demands for higher speed and higher image quality have been increasing.
An image forming apparatus as shown in FIG. 13 has been proposed.

In this image forming apparatus, an image forming unit (image forming unit) is provided for each of four developers.
In each image forming section, an image forming process is performed on a photosensitive drum as an image carrier to form a visible image for each color, and the visible images are sequentially transferred to a transfer material supplied from the outside.
This is an electrophotographic digital color image forming apparatus which collectively fixes and obtains a color image on a transfer material. The greatest advantage of this method is that high speed can be achieved.

The image forming apparatus includes first, second, third, and fourth four image forming units PM, PC, PY, and PK in a main body of the apparatus. The fixing unit 15 is disposed on the left side opposite to the unit 14. An endless transfer material transporting means for transporting the transfer material, in this example, a transport belt 13 is suspended between a plurality of rollers below the path from the paper feed unit 14 to the fixing device 15 in the apparatus main body. Are located. This transport belt 13
Is rotated in the direction of the arrow in the figure, carries the transfer material fed through the paper feeding unit 14, and sequentially moves to each of the image forming units PM, PC, PY, and PK arranged above the conveyor belt 13. Transport.

Each of the image forming units PM, PC, PY, and PK has substantially the same configuration, and is usually a photosensitive drum 21M, 21C, 2C, which is an image carrier that is driven to rotate in the direction of the arrow in FIG.
1Y, 21K, and each photosensitive drum 21 (21M, 21K).
C, 21Y, 21K), a primary charger 22 (22M, 22C, 22Y, 22) for uniformly charging the photosensitive drum.
K), an image exposure device 23 for forming an electrostatic latent image on a photosensitive drum
(23M, 23C, 23Y, 23K) and developing units 24 (24M, 24K) for developing the electrostatic latent images formed on the photosensitive drums.
C, 24Y, 24K), and a corona charger 26 (26M, 2K) which transfers a toner image of a visible image obtained by development to a transfer material.
6C, 26Y, 26K) and a drum cleaner 25 (25M, 2M) for removing transfer residual toner remaining on the photosensitive drum.
5C, 25Y, and 25K) are sequentially arranged in the drum rotation direction.

The developing device 24M contains magenta toner.
The developing device 24C stores cyan toner, the developing device 24Y stores yellow toner, and the developing device 24K stores black toner.

The above-mentioned image exposure unit 23 (23M to 23K)
In this example, is an LED head in which LED light emitting elements are arranged in the generatrix direction of the drum, and is separated into a number of pixels by an image pickup element such as a color CCD, read, and converted into digital signals for each color. Upon receiving a digital pixel signal input for an image, the primary charger 22
(22M to 22K) and the developing device 24 (24M to 24K), the surface of the photosensitive drum 21 is exposed to form an electrostatic latent image of a corresponding color.

A pixel signal corresponding to the magenta component image of the color image is supplied to the image exposure device 23M, a pixel signal corresponding to the cyan component image of the color image is supplied to the image exposure device 23C, and the color signal of the color image is supplied to the image exposure device 23Y. A pixel signal corresponding to a yellow component image is input to the image exposure device 23K, and a pixel signal corresponding to a black component image of a color image is input to the image exposure device 23K.

A pair of adsorption chargers (not shown) for adsorbing the transfer material is disposed between the first image forming unit PM and the paper supply unit 14 with the conveyance belt 13 interposed therebetween. I have.
Between the fourth image forming section PK and the fixing device 15, a charge removing charger (not shown) for separating the transfer material adsorbed on the transport belt 13 is provided. An AC voltage is applied to the charger from a power supply (not shown).

In the above image forming apparatus,
The transfer material fed from the printer is electrostatically attracted onto the transport belt 13 and transported as the transport belt 13 moves. Each of the photosensitive drums 21M to 21K corresponds to the transfer of the transfer material.
Charging by primary chargers 2M to 2K, image exposure device 23M to
An electrostatic latent image is formed by 23K, and a latent image is developed by developing units 24M to 24K. A magenta toner image is formed on the photosensitive drum 21M of the first image forming unit PM, and a photosensitive drum of the second image forming unit PC is formed. A cyan toner image is formed on the photosensitive drum 21Y of the third image forming portion PY, and a black toner image is formed on the photosensitive drum 21K of the fourth image forming portion PK.

In general, an electrostatic latent image developing method employs a two-component developing method using a two-component developer in which a toner and a magnetic carrier are mixed, from the viewpoint of image quality stability. In order to stabilize the charge amount of the toner, it is necessary to constantly control the mixing ratio with the magnetic carrier, and the configuration of the developing device becomes complicated as compared with the one-component developing method without using the magnetic carrier. There is.

For this reason, in recent years, a full-color image forming apparatus adopting a developing method using a non-magnetic one-component developer (non-magnetic toner) and having a simple configuration of a developing device and the like has been proposed and put into practical use.

In this embodiment, the non-magnetic one-component developing method is adopted for the developing units 24M to 24K. FIG. 14 shows the outline. The developing device 24 (24M to 24K) includes a developing roller 1 which is driven to rotate in the direction of an arrow as a developer carrier in an opening of a developing container 3 containing a non-magnetic toner (non-magnetic one-component developer). A toner supply / recovery roller 17 as a developer supply / recovery member and a regulating blade 18 as a developer regulating member are provided in contact with the developing roller 1.

The toner supply / recovery roller 17 is provided with an elastic member 1 such as urethane foam on the outer peripheral surface of a core metal 17a such as SUS.
7b, the non-magnetic toner stored in the developing container 3 is supplied to the surface of the developing roller 1 by rotating while being elastically contacted with the surface of the developing roller 1 by the elastic member 17b. The developing roller 1 has a function of scraping off the developing residual toner that has returned to the developing container 3 without being used in the development with the rotation of the developing roller 1 from the surface of the developing roller 1.

The regulating blade 18 is formed by bonding an elastic member 18b such as urethane rubber to a supporting member 18a made of phosphor bronze or the like.
By elastically abutting against the surface of the developing roller 1 to regulate the toner carried on the developing roller 1, the toner is formed in a thin layer of toner and acts to impart electric charge to the toner.

Each toner image formed on the photosensitive drum 21 by the development by the developing unit 24 is transferred to the transfer charging unit while the transfer material sequentially passes below the photosensitive drum 21 by being transported by the transport belt 13. By the operation of 26, the toner image is sequentially transferred onto the transfer material in a superimposed manner, and is formed into a composite color image in which four color toner images are superimposed on the transfer material.

After passing through the fourth image forming portion PK, the transfer material is discharged by a discharging charger to which an AC voltage is applied, and is separated from the transport belt 13. The separated transfer material is sent to a fixing device 15, where the transferred toner image is fixed, and then discharged to a tray 16 of an image forming apparatus as a full-color print image.

On the other hand, the transfer residual toner adheres to the photosensitive drum 21 after the transfer of the toner image, and when the toner enters the transfer process at the time of the next image formation, it appears as a stain on the transferred image. To prevent this, each photosensitive drum 21
The upper transfer residual toner is removed by the drum cleaner 25. In this embodiment, an elastic blade that contacts the photosensitive drum 21 and scrapes off the toner is used as the cleaner 25. The removed toner is stored in a waste toner box provided in parallel with each cleaner.

[0019]

In recent years, the image forming apparatus using the non-magnetic one-component developing method has been required to be further reduced in size and cost, and the image forming process has been shortened.
(Including some steps omitted) have been studied.

Conventionally, there has been proposed a cleaner-less image forming apparatus in which the cleaning step is omitted in the above image forming step. However, if the drum cleaner 25 is simply omitted, the following problems occur.

If there is no cleaning means for cleaning the surface of the photosensitive drum 21, untransferred toner, paper dust and the like accumulate on the photosensitive drum, thereby blocking uniform charging and image exposure for forming an electrostatic latent image. Therefore, potential unevenness occurs in the electrostatic latent image, and density unevenness of the output image occurs.

The developing device 24 supplies and collects the toner to and from the developing roller 1 by rotating the toner supplying and collecting roller 17 in contact with the developing roller 1 and rubbing it. Since the application is performed by the contact friction when the toner passes through the regulating blade 18, the mechanical load applied to the toner in the developing container 3 until it is used for development on the photosensitive drum 21M is extremely large. The damage of the toner is very large as compared with other developing methods.

Further, depending on the arrangement position and the rotation direction of the toner supply / recovery roller 17, the toner that did not contribute to the development could not be completely recovered, and the toner sometimes remained on the developing roller 1. The toner remaining on the developing roller 1 passes through the regulating blade 18 again and is conveyed to the developing area. If such a process is continuously repeated, the charge amount and fluidity of the toner are reduced. The controlled external additive or the like is embedded in the toner due to the mechanical friction and heat accumulation received each time, and the deteriorated toner cannot obtain the desired charging characteristics and fluidity.

This deteriorated toner causes many problems during the image forming process. For example, when the deteriorated toner contributes to the development, an insufficient development characteristic may not be obtained, which may cause a development failure, or may cause a transfer failure such as a defective image. Further, the supply of new toner onto the developing roller 1 is hindered, and the toner coating amount (coating amount) decreases, which may cause a density defect or the like. Further, if the deteriorated toner is fused to the nip portion of the regulating blade 18 or the surface of the developing roller 1, coating defects such as streaks will occur, and the charge application to the toner newly supplied on the developing roller will be hindered. For this reason, the uncharged toner is conveyed to the developing unit, and image defects such as fog and unevenness may occur.

In the above-described non-magnetic one-component developing method, not only a large load is applied to the toner but also a large load is applied to the developing device 24 itself, and the sponge-type roller as described above is used for the toner supply / recovery roller 17. In this case, when the rubbing of the developing roller 1 is performed for a long time, the friction of the developing roller itself,
Due to damage, toner clogging, and the like, the role of the toner supply / recovery roller may be insufficient, and good toner supply and recovery may not be achieved.

As described above, the one-component developing method using a non-magnetic toner has a simple structure of a developing device and enables good development. However, the load on the toner and the developing device is large, and the conventional one-component developing method using a magnetic material. And long-term stability and durability are remarkably poor as compared with the two-component developing method. Therefore, the non-magnetic one-component developing method is mainly used in a cartridge type developing device in which a whole developing device is exchanged at the time of toner supply, and a type in which a developer used in a copying machine is supplied. Currently, it is not widely used in some developing devices.

Further, in recent years, development of toner capable of fixing at a lower temperature has been promoted for the purpose of reducing power consumption, and accordingly, a low-stress developing process corresponding to low-temperature fixing toner is expected. However, a non-magnetic one-component developing method having such characteristics has not yet been developed.

Accordingly, an object of the present invention is to significantly reduce the load on the toner during development, particularly the load on the toner when applying a charge and supplying the toner to the developing roller when forming a color image by developing with a plurality of developing units. As a result, a low-stress coat compatible with low-temperature fixing toner can be realized, and a toner layer that does not contain reversal toner or uncharged toner can be formed on the developing roller, and a cleaner-less image forming process can be realized. It is an object of the present invention to provide an image forming apparatus capable of obtaining a high-quality color image over a long period of time and realizing a small size and low cost.

[0029]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
A plurality of image forming units are provided along the transfer material conveying means,
Each of the image forming units includes an image carrier on which an electrostatic latent image is formed, and a developing device that develops the electrostatic latent image formed on the image carrier using a non-magnetic one-component developer. In an image forming apparatus for sequentially transferring a visible image obtained by the development in each of the image forming units onto a transfer material and transferring the same, the developing device includes: a developing container containing a non-magnetic one-component developer; With respect to the rotating developer carrier that is provided opposite to the image carrier at the opening of the container, a power supply that applies a voltage to the developer carrier, and a rotation direction of the developer carrier,
On the upstream side of the developing section where the developer carrier and the image carrier are opposed, a rotating developer supply member that is arranged in non-contact with the developer carrier, and with respect to the rotation direction of the developer supply member, A developer flow path control member arranged at one end in contact with the developer supply member at an upstream side of an opposing portion between the developer carrier and the developer supply member; and a developer supply member and a developer flow member. A power source for applying a voltage to the path control member, and a rotation direction of the developer carrier, the upstream of the developing unit and the downstream of the developer flow path control member, and the developer carrier. Developer regulating means arranged in contact with the developer carrying means, with respect to the rotation direction of the developer carrying member, downstream of the developing section, developer collecting means arranged facing the developer carrying body and the image carrying body; A power supply for applying a voltage to the developer collecting means; An image forming apparatus configured to remove and collect the remaining developer remaining on the developer carrier and the remaining developer transferred on the image carrier by electrostatically collecting the developer; It is.

According to the present invention, the developer collecting means includes:
A developer collecting roller for electrostatically removing and collecting the developer remaining after development and the developer remaining after transfer; The developer collecting roller includes a metal roller, and is disposed so as to be in non-contact with the developer carrier and the image carrier. Alternatively, the developer collecting roller is formed of an elastic roller, and is disposed so as to contact at least one of the developer carrier and the image carrier. Further, the developer carrying member is formed of a metal roller, and is disposed to face the image carrying member in a non-contact manner. Alternatively, the developer carrying member is formed of an elastic roller, and is arranged in contact with and opposed to the image carrying member. The developer collecting means may include a scraper that contacts the surface of the developer collecting roller and removes the developer collected in the developer collecting row.

[0031]

Embodiments of the present invention will be described below in more detail with reference to the drawings.

Embodiment 1 FIG. 1 is a schematic structural view showing an embodiment of the image forming apparatus of the present invention.

The color image forming apparatus of this embodiment shown in FIG. 1 is similar to the conventional color image forming apparatus shown in FIG.
A first, second, third, and fourth four image forming units PM, PC, PY, and PK are provided in the apparatus main body, and a sheet feeding unit 14 is provided at one end, that is, on the left side of FIG. A fixing device 15 is provided on the right side. Further, in the present embodiment, an endless transfer material transporting means (transfer material transport belt) 13 for transporting the transfer material is provided between a plurality of rollers above the path from the paper supply unit 14 to the fixing device 15 in the apparatus main body. It is arranged suspended. The transport belt 13 is rotatably driven in the direction of the arrow in the figure, carries the transfer material fed through the paper feed unit 14, and has the image forming units PM, PC, and PY arranged below the transport belt 13. , PK sequentially.

Each of the image forming units PM, PC, PY, and PK has substantially the same structure, and is generally a photosensitive drum 21M, 21C, or 2C, which is an image carrier that is driven to rotate in the direction of the arrow in FIG.
1Y, 21K, and each photosensitive drum 21 (21M, 21K).
C, 21Y, 21K), primary chargers 22M, 22C, 22Y, 22K for uniformly charging the photosensitive drum, and an image exposing device 23 (23) for forming an electrostatic latent image on the photosensitive drum.
M, 23C, 23Y, and 23K), and a developing device 24 (24M, 24C, 2C) for developing the electrostatic latent image formed on the photosensitive drum.
4Y, 24K), a corona charger 26 (26M, 26C, which transfers a toner image of a visible image obtained by development to a transfer material).
26Y, 26K) are sequentially arranged in the drum rotation direction.

In the present invention, the image forming apparatus is cleaner-less, and a drum cleaner for removing transfer residual toner remaining on the photosensitive drum is not provided.

The developing device 24M contains magenta toner.
The developing device 24C stores cyan toner, the developing device 24Y stores yellow toner, and the developing device 24K stores black toner.

The above-mentioned image exposure unit 23 (23M to 23K)
Is an LED head in which LED light emitting elements are arranged in the generatrix direction of the drum in the present embodiment, and exposes the surface of the photosensitive drum 21 (21M to 21K) in accordance with a desired image signal, and An electrostatic latent image is formed. That is, a pixel signal corresponding to the magenta component image of the color image is supplied to the image exposure device 23M, a pixel signal corresponding to the cyan component image of the color image is supplied to the image exposure device 23C, and the yellow component of the color image is supplied to the image exposure device 23Y. A pixel signal corresponding to the image is input to the image exposure device 23K, and a pixel signal corresponding to the black component image of the color image is input to the image exposure device 23K.

A pair of adsorption chargers (not shown) for adsorbing the transfer material is disposed between the first image forming unit PM and the paper feeding unit 14 with the conveyance belt 13 interposed therebetween. I have.
Between the fourth image forming section PK and the fixing device 15, a charge removing charger (not shown) for separating the transfer material adsorbed on the transport belt 13 is provided. An AC voltage is applied to the charger from a power supply (not shown).

The image forming process and the cleaning mechanism in the above image forming apparatus will be briefly described. Image forming unit PM
This is basically the same in PK.

In the first image forming section PM, the photosensitive drum 21M is rotated in the direction of the arrow in the figure, and during the rotation process, the surface of the photosensitive drum is uniformly charged to a desired polarity and potential by the charger 22M. The exposure unit 23M performs image exposure according to desired image data to form an electrostatic latent image on the surface of the photosensitive drum. Next, in a developing unit where the photosensitive drum 21M and the developing roller 1 of the developing device 24M are opposed to each other, the electrostatic latent image on the photosensitive drum is developed with the non-magnetic toner on the developing roller 1, and the electrostatic latent image is formed on the photosensitive drum. To form a magenta toner image corresponding to.

The magenta toner image formed on the photosensitive drum 21M is transferred to a photosensitive drum and a transfer charger (corona charger).
A transfer bias is applied to the transfer charger 26M to transfer the transfer material conveyed to the transfer unit facing the transfer unit 26M.

The transfer material on which the magenta toner image has been transferred in this manner is sent to the second image forming unit PC, and the photosensitive drum 2 is subjected to the same image forming process as the image forming unit PM.
The yellow toner image formed on 1C is transferred onto the transfer material from the magenta toner image in a superimposed manner. Similarly, the transfer material is sequentially sent to the third and fourth image forming units PY and PK, where the same process is repeated to form a full-color image in which four color toner images are superimposed and transferred on the transfer material. . Then, the transfer material is introduced into the fixing device 14, and the toner image is heated and fixed on the transfer material, whereby a full-color image is obtained on the transfer material, and a series of image forming steps is completed.

On the other hand, at the time of the above-described development, each developing device 24 (2
4M to 24K), the remaining toner not contributing to the development on the developing roller 1 is formed by the developing bias applied to the developing roller 1 and the collecting bias applied to the toner collecting roller 8 of the developing device 24. Due to the applied electric field, the toner adheres to and is collected by the toner collecting roller 8, and is returned into the developing device 24.

At the time of the above-described transfer, the transfer residual toner remaining on the photosensitive drums 21 (21M to 21K) without being transferred to the transfer material is again charged and exposed while being carried on the photosensitive drums 21. After proceeding to the next step, the electric potential formed by the electrostatic latent image newly formed on the photosensitive drum 21 and the electric field formed by the bias applied to the toner collecting roller 8 at the portion facing the toner collecting roller 8 The toner adheres to and collects on the toner collecting roller 8 and is returned into the developing device 24.

As described above, according to the present invention, the untransferred toner on the photosensitive drum 21 is a non-image portion of a new electrostatic latent image.
Only the untransferred toner present in the (non-exposed portion) is removed and collected on the toner collecting roller 8 side. Other transfer residual toner present in the image portion (exposure portion) of the new electrostatic latent image is used for development in the next development process, and is introduced into the development process while being carried on the photosensitive drum 21. Has no effect.

Thereafter, similar development, transfer and fixing steps are performed on the new electrostatic latent image, and such image formation is repeated.

Hereinafter, the developing device used in the present invention and a cleanerless mechanism using the developing device will be described in detail. The developing units 24M to 24K are basically the same.

As shown in FIG. 2, in the present invention, the developing device 24 (24M to 24K) has a developing container 3 containing a non-magnetic toner (non-magnetic one-component developer).
The developing device 1 includes a developing roller 1, a toner supply brush 4, a toner flow control member 5, a toner regulating blade 7, the toner collecting roller 8, a scraper 9 for removing toner, and a toner stirring member 10. The inside of the developing container 3 is partitioned by a partition member 12 extending to a position short of the opening, and a communication port 12 a is provided below the partition member 12.

The developing roller 1 is opposed to the photosensitive drum 21 in the opening of the developing container 3 at a predetermined interval, and is driven to rotate in the direction of the arrow in the figure. In this embodiment, a metal roller such as SUS or aluminum is used as the developing roller 1. The developing roller 1 is connected to a power source 2 for applying a predetermined developing bias.

In this embodiment, the developing bias power supply 2
The peak-to-peak voltage Vpp is about 2 kV, the frequency f is about 1.8 kHz, and the CD offset value Vdc is -450 V
AC + DC bias is set.

The toner supply brush 4 is for taking in the non-magnetic toner in the developing container 3 and supplying it to the developing roller 1. The toner supplying brush 4 rotates the developing roller 1 at a distance of about 100 μm to 1 mm from the developing roller 1. It is arranged so as to be rotatable in the same direction as the direction (in the opposite direction at the nearest part). The core of the toner supply brush 4 is supplied with a desired D
A voltage on which the C voltage = Vf is superimposed is applied, and the developing roller 1
And a desired electric field is formed between them.

The fibers of the toner supply brush 4 may be conductive fibers only, but in this embodiment, the fibers are as shown in FIG.
As shown in (b), a brush member in which two types of conductive fibers 30 having low resistance of about 10 ² to 10 ⁸ Ωcm and insulating fibers 31 having high resistance of about 10 ⁸ to 10 ¹⁵ Ωcm are mixed,
A fur brush wound around a metal core such as SUS is used.

In this embodiment, since the toner having a negative charge polarity is used as the developer, the above-mentioned insulating fiber 31 preferably has a positive charge polarity. As nylon fiber (10 ⁸ -10 ¹⁵
Ωcm). Of course, it is not limited to nylon, and the type of insulating fiber may be selected according to the characteristics of the toner. In the case of this embodiment, a fiber such as rayon may be used.

The first condition is that the conductive fiber 30 satisfies the resistance value in the above range. However, most of the conductive fiber has a conductive agent such as carbon dispersed in an insulating resin as a raw material of the insulating fiber. In many cases, the dispersion method varies depending on the fiber manufacturer, and the conductive agent is not always exposed on the entire surface of a single fiber (monofilament). That is, as shown in FIG. 4 showing a cross section of a single fiber of the conductive fiber 30, the surface of the single fiber has a conductive portion 30a.
In addition, there is an insulating part 30b. Therefore, the insulating part 3
In consideration of the contact of the toner with Ob, it is preferable to select an insulating resin for the conductive fiber that is positively charged with respect to the toner. In this embodiment, a nylon resin is used.

In this embodiment, the toner is formed into a cloud by the toner supply brush 4 and the toner is supplied to the developing roller 1. For this reason, both the conductive fiber 30 and the insulating fiber 31 of the brush 4 need elasticity, and their fineness is about 1 to 10 denier / filament.
200,000 / inch ² planting density have, and the pile length is 1
It was set to be 〜１０10 mm.

The toner flow path control member 5 serves to cloud the toner from the toner supply brush 4 and strike the toner toward the developing roller 1, and is arranged so as to be in contact with the toner supply brush 4. Have been. In the present embodiment, as the toner flow path control member 5, a thin plate having a thickness of about 100 μm to 1 mm made of a metal such as SUS or phosphor bronze is used. Although the toner flow path control member 5 has a straight shape made of a thin plate, the shape is not limited to this. Depending on the direction in which the toner is clouded, the toner flow path control member 5 can be formed into a shape suitable for this.

On the contact surface of the toner flow path control member 5 with the toner supply brush 4, in consideration of the charge application to the toner interposed therebetween, a resin having a high charge providing ability to the toner, for example, carbon to nylon is used. Disperse and increase the resistance to 10
Those adjusted to about ⁵ Ωcm may be laminated. Thereby, the charge application to the toner by the toner flow path control member 5 is added, and the charge application to the toner is further stabilized.

Control blade 7 as toner control means
Is for regulating the layer thickness of the toner coated on the developing roller 1. In this embodiment, a urethane having a JISA hardness of 50 ° to 70 ° is attached to the tip of a thin metal plate having a thickness of about 0.1 mm. Elastic body 7 made of rubber such as rubber or silicone rubber
a is arranged so as to be in contact with the developing roller 1 using a blade in which a is laminated.

The toner collecting roller 8 electrostatically collects the transfer residual toner remaining on the photosensitive drum 21 in the transfer section and the development residual toner remaining on the developing roller 1 without contributing to the development in the developing section. With an interval of about 100 μm to 1 mm from the developing roller 1 and an interval of about 100 μm to 1 mm with the photosensitive drum 21, as shown by an arrow in the drawing, the direction opposite to the rotation direction of the developing roller 1 and the photosensitive drum 21 (recently). So that it can rotate in the same direction at the contact part)
They are installed facing each other. The toner collection roller 8 has a power source 1
1 applies a desired DC voltage Vc, and a desired electric field is formed between the developing roller 1 and the photosensitive drum 21.

In this embodiment, the toner collecting roller 8 is formed by processing the surface of the metal roller into a mirror surface. However, in consideration of the toner collecting efficiency, the surface of the metal roller is processed with a fluorine resin such as Teflon. May be performed. For example, the surface of a metal roller is obtained by rapidly plating nickel, chrome, etc. on a metal roller surface and dissolving a fluorine-based resin into cracks on the plating surface formed at that time. Resin (insulation part) and plating part
Due to the electric field concentration effect of the (conductive portion), the undeveloped toner becomes easier to collect. By performing such surface processing, the wear resistance of the roller surface is also improved.

Scraper 9 as toner stripping means
Is for removing the toner collected and adhered to the toner collecting roller 8 from the surface of the roller 8 and returning the toner to the toner storage section A as shown in FIG. 5. In this embodiment, the scraper 9 is made of urethane. It is made of a rubber member such as rubber, silicone rubber, or the like, and is arranged so that the front end of the rubber member comes into edge contact with the surface of the toner collecting roller 8.

The rubber member forming the scraper 9 preferably has a rubber hardness of 50 ° to 70 ° in JISA hardness so that the toner can be mechanically scraped off from the toner collecting roller 8. The edge position of the scraper 9 is set so that the scraped toner is surely returned to the toner storage section A.
The toner collection roller 8 is set at the lower half circumference position.

The partition member 12 is provided to a position below the portion of the developing roller 1 opposed to the toner collecting roller 8, and separates the toner storing section A and the toner supplying section B from the toner collecting roller 8. The scraped toner is prevented from scattering to the toner supply section B side. Therefore, it is possible to more reliably return the undeveloped toner to the toner storage section A.

The partition member 12 transfers the toner, which does not have a desired charge, of the toner clouded by the toner supply unit B to the outside of the developing device through the gap between the developing roller 1 and the collecting roller 8. It is also effective in preventing scattering.

In this embodiment, the non-magnetic toner is formed by mixing and dispersing a colorant and a negative charge control agent in a polystyrene or polyester-based thermoplastic resin, and pulverizing the mixture. The weight average particle size is 5 μm or more. Was used. Further, an OPC photosensitive member was used for the photosensitive drum 21M, and a reversal developing method in which a negative non-magnetic toner was attached to an image exposure portion was adopted as an image developing method.

As shown in FIG. 5, the inside of the developing container 3 is
Conceptually, area A as a toner storage section, area B as a toner supply section, and area C as a toner recovery section
Can be divided into two. The toner in the developing container 3 is always circulated in the direction of the area A → B → C → A.

The toner stored in the toner storage section A is
The toner is fed to the toner supply brush 4 of the toner supply unit B through the communication port 12a below the partition member 12 by the conveyance by the stirring member 10. The toner sent to the toner supply brush 4 adheres to the spaces between the fibers of the brush 4 and the surface of the fibers by the mirror force or the like, and is conveyed toward the toner flow path control member 5 with the rotation of the brush 4. And a stable charge is applied. As shown in FIG. 6, after the toner T passes through the toner flow path control member 5, the toner T is repelled in the rotation direction of the brush 4 by the elastic force when the fibers of the toner supply brush 4 come off the flow path control member 5. Then, it flies in the direction of arrow A in the form of a cloud.

Since the toner supply brush 4 is brought into contact with the toner flow path control member 5 to eject the toner in the brush 4, uncharged toner and inverted toner remaining between the brush fibers are also discharged. And the clogging of the fibers by these toners can be prevented.

An electric field is formed between the toner supply brush 4 and the development roller 1 by the development bias applied to the development roller 1 and the bias applied to the toner supply brush 4 by the power source 6, The cloud-shaped toner flying in the direction A is attracted to the developing roller 1 by the electric field as shown by the arrow B, and is carried on the surface of the developing roller 1.

For example, as shown in FIG. 7A, when the DC component of the developing bias is set to Vdc = −450 V,
A bias in which a DC voltage of about Vf = −750 V is superimposed on the developing bias, that is, Vpp and Vf are the same as the developing bias, and the DC component is −1.2 kV (Vdc + Vf). A
If a C + DC bias (AC is omitted in the figure) is set, the negatively charged toner is attracted from the toner supply brush 4 to the developing roller 1 by the action of the electric field due to the DC voltage difference (-750 V). It is being done.

The toner supplied on the developing roller 1 in this way is carried on the developing roller 1 by the mirror force, and is then conveyed to the regulating blade 7, where the toner layer thickness is adjusted by the regulation by the blade 7. At the same time, a further triboelectric charge is applied to form a dense toner layer having a uniform charge amount distribution.

As described above, the charged toner is once clouded, and the toner is supplied to the developing roller 1 in a non-contact manner by the electric field, so that the mechanical stress on the toner can be significantly reduced, and the charged toner can be sufficiently charged. By supplying only the toner thus obtained onto the developing roller 1, a very sharp toner layer with little deviation in the charge amount distribution can be formed.

The toner formed on the toner layer on the developing roller 1 is uniformly charged by a charger 2 at VD = about -700 V, and a photosensitive drum 21 on which an electrostatic latent image is formed by image exposure by an image exposing unit 3. FIG. 7 (b)
As shown in FIG. 3, the latent image potential on the photosensitive drum 21 (the exposed portion V
L = −100 V, unexposed portion VD = −700 V) and the developing bias applied to the developing roller 1 (Vpp = about 2 kV,
f = about 1.8kHz, Vdc = -450V)
The toner image adheres to the exposed portion due to the electric field (not shown), and a toner image corresponding to the latent image is formed on the photosensitive drum 21.

As shown in FIG. 8A, the residual toner that has returned to the developing container 3 while being carried on the developing roller 21 without contributing to the development is applied to the DC applied to the toner collecting roller 8 as shown in FIG. The toner collection roller is driven by an AC + DC electric field caused by a bias Vc of +500 V and a developing bias (Vpp = about 2 kV, f = about 1.8 kHz, Vdc = −450 V) applied to the developing roller 1 (AC is omitted in the figure). 8 is electrostatically attached to the surface of the substrate 8 and collected. The collected toner is transferred to the developing device 3 by the rotation of the toner collecting roller 8.
And is scraped off by the scraper 9 and stored in the toner storage section A.

As described above, if the scraper 9 is used for the toner collecting roller 8, the surface of the collecting roller 8 can be always maintained at a fresh electrode surface with respect to the developing roller 1, and the gap between the collecting roller 8 and the developing roller 1 can be maintained. Therefore, a stable electric field can be always formed.

As described above, the toner remaining after development is completely separated from the developing roller 1 and is reliably collected in the toner storage section A, so that the area A → B in FIG.
A toner circulation path in the direction of → C → A can be formed, and without applying a continuous load to the toner, heat generation of the toner itself can be prevented, and deterioration of the toner can be suppressed to a minimum. As a result, the life of the toner is significantly extended, and a good image can be formed over a long period of time.

The toner image formed on the photosensitive drum 21 is conveyed in the direction of the transfer charger 26, and is transferred by a transfer bias (applied to the transfer charger 26) at a transfer section (opposite to the transfer charger 26). The toner image transferred thereon and then transferred by the fixing device 14 is fixed on the transfer material. The photosensitive drum 2 is not transferred to the transfer material in the transfer section.
The transfer residual toner remaining on the 1M is carried on again to the next step of charging and exposure while being carried on the photosensitive drum 21.

The untransferred toner often includes an uncharged toner or an inverted polarity toner that has been included during development, or an uncharged toner or an inverted polarity toner whose charge polarity has been changed by charge injection or discharge during transfer. I have. When the photosensitive drum 21 carrying these transfer residual toners is charged again to VD = -700 V by the charger 2, the transfer residual toner on the photosensitive drum 21 is also uniformly recharged to a desired negative polarity at the same time. .

A new electrostatic latent image is formed on the photosensitive drum 21 by the image exposing device 3, and the electrostatic latent image is conveyed to a portion facing the toner collecting roller 8 while carrying the untransferred toner on the surface. Will be done. As shown in FIG.
Since a DC bias of Vc = + 500 V is applied to the toner collecting roller 8, the potential of the non-image portion (unexposed portion) (VD = −700 V) of the new electrostatic latent image is
An electric field is generated in which the transfer residual toner on the photosensitive drum 21 is attracted to the collection roller 8 side. On the other hand, with respect to the potential of the image portion (exposure portion) (VL = −100 V) of the new electrostatic latent image, an electric field for attracting the transfer residual toner remaining in that portion to the collection roller 8 is formed. However, the recovery contrast is smaller than that of the non-image portion (VD = −700 V), so that depending on the toner, the recovery contrast may remain as it is.

The voltage Vc applied to the toner collecting roller 8 is not limited to the value described in the present embodiment, but includes the distance between the developing roller 1 and the photosensitive drum 3 (3M to 3K), the charge amount of the toner, and the like. The DC and AC bias may be applied in some cases.

Embodiment 2 FIG. 9 is a sectional view showing a developing device according to another embodiment of the present invention.

In the first embodiment, as shown in FIG. 2, the toner collecting roller 8 composed of a metal roller of the developing unit 24 is used in a non-contact manner with the photosensitive drum 21 and the developing roller 1, and the transfer residual toner on the photosensitive drum 21 is used. And the toner remaining after development on the developing roller 1 were collected.

In this embodiment, as shown in FIG. 9, a toner collecting roller 8A composed of an elastic roller is used for the developing device 24, and the transfer residual toner is collected in a contact manner.
The toner collecting roller 8A was used in contact with the photosensitive drum 21. The toner collecting roller 8A was used in contact with the developing roller 1 as in Example 1. Other configurations of the present embodiment are basically the same as those of the first embodiment. In FIG. 9, the same reference numerals as those shown in FIG. 2 denote the same members.

The toner collecting roller 8A of this embodiment is composed of an elastic roller having a single layer or a plurality of elastic layers on a cored bar. The elastic layer is made of silicone rubber, NBR rubber, EPDM rubber, or the like. A general rubber material such as urethane rubber can be used. Although the surface of the elastic layer may be left as it is, the surface may be coated with a conductive resin obtained by dispersing carbon or the like in a resin such as nylon. The rubber hardness of the elastic layer is measured according to JIS, including the conductive resin film on the surface.
A value of about 20 to 70 [deg.] Measured by a rubber hardness meter is appropriate. The surface of the elastic layer preferably has a surface roughness Rz of 10 or less in consideration of the releasability of the toner, and can be set according to the particle size and shape of the toner to be used.
The resistance value of the toner collecting roller 8A is preferably set to a volume resistivity of about 10 ³ to 10 ⁹ Ωcm including the conductive resin film.

When the toner collecting roller 8A in contact with the photosensitive drum 21 is used as in this embodiment, the collecting roller 8
Since the voltage applied to A is smaller than that of the non-contact type toner collecting roller, the voltage applied to the collecting roller 8A by the power supply 11 is set to about V = + 200V.

The transfer residual toner (toner on the unexposed portion) on the photosensitive drum 21 is an electrostatic latent image (exposed portion potential VL = −100 V, unexposed portion potential VD = −) on the photosensitive drum.
Due to the action of a DC electric field formed by the bias applied to the collecting roller 8A and the toner collecting roller 8A, the toner adheres to the toner collecting roller 8A contacted from the photosensitive drum 21 and is collected. Of course, the transfer residual toner on the photosensitive drum 21 can be sufficiently collected simply by electrically grounding the collection roller 8A.

As described above, by using the toner collecting roller 8A made of an elastic roller and making contact with the photosensitive drum 21M, the collection efficiency of the transfer residual toner on the photosensitive drum 21 is improved.

On the other hand, the residual toner on the developing roller 1 is applied to the developing bias (Vpp = about 2 kV, f = about 1.8 kHz, Vdc = −450 V) applied to the developing roller 1 and the bias applied to the toner collecting roller 8A. Of the developing roller 1 by the action of the AC + DC electric field formed by the potential difference
To the non-contact toner collecting roller 8A,
Collected without contact.

In the above description, an elastic roller made of a rubber material is used as the toner collecting roller.
A sponge-like elastic layer having a low hardness of about 30 to 60 ° in SA hardness is formed, and a high hardness silicone rubber, NBR rubber, EPDM rubber, urethane rubber or the like having a high JISA hardness of 50 to 80 ° C. is formed thereon. An elastic roller provided with a rubber-like elastic layer may be used, and a sufficient effect is achieved.

Embodiment 3 FIG. 10 is a sectional view showing a developing device according to another embodiment of the present invention.

In the second embodiment, a toner collecting roller 8A made of an elastic roller made of a rubber material is used in contact with the photosensitive drum 21 and is used in a non-contact manner with the developing roller 1, so that the transfer residual toner on the photosensitive drum 21 is removed. The collection was carried out by a contact method, and the collection of the residual toner on the developing roller 1 was carried out by a non-contact method. However, in the present embodiment, this was reversed as shown in FIG.

That is, the toner collecting roller 8A is used in contact with the developing roller 1 and is used in a non-contact manner with the photosensitive drum 21, and the remaining toner remaining on the developing roller 1 is collected in a contact manner. The above-mentioned transfer residual toner was collected in a non-contact manner.

In this embodiment, the desired DC voltage Vc is applied to the developing bias by the power supply 11 on the toner collecting roller 8A.
Is applied, and DC with the developing roller 1 is applied.
The residual toner on the developing roller 1 is collected based on the voltage difference. That is, the DC component of the developing bias is Vdc
If the power supply 11 is set to apply a DC voltage of about Vc = + 450 V to the toner collecting roller 8A, the remaining toner in the developing roller is set to the developing roller 1 by the action of an electric field due to the DC voltage difference of 450 V. The toner adheres to the toner collecting roller 8A, which comes into contact therefrom, and is collected by contact.

On the other hand, the transfer residual toner on the photosensitive drum 21 is replaced with a new electrostatic latent image (exposure portion potential VL =
-100 V, unexposed portion potential VD = -700 V) and a bias applied to toner collection roller 8A (a voltage obtained by superimposing a desired DC voltage Vc on a developing bias), causing photosensitive drum 21 to be exposed to light. The toner is transferred to and adheres to the toner collecting roller 8A, which comes into contact therewith, and is collected in a non-contact manner.

As described above, by using the toner collecting roller 8A made of an elastic roller and bringing it into contact with the developing roller 1, the collecting efficiency of the developing residual toner on the developing roller 1 is improved.

Embodiment 4 FIG. 11 is a sectional view showing a developing unit according to still another embodiment of the present invention.

In the first to third embodiments, the developing roller 1 of the developing device 4 is made of metal. However, in this embodiment, as shown in FIG. The contact developing method of contacting the photosensitive drum 21 is employed. The present invention is also applicable to a case where the developing device 4 is an image forming apparatus employing such a contact developing method.

In this embodiment, the developing roller 1A is an elastic roller having a single or a plurality of elastic layers on a cored bar. As the material of the elastic layer, general rubber materials such as silicone rubber, NBR rubber, EPDM rubber, urethane rubber and the like can be used. Although the surface of the elastic layer may be left as it is, the surface may be coated with a conductive resin obtained by dispersing carbon or the like in a resin such as nylon. The rubber hardness of the elastic layer is measured by JI including the conductive resin film on the surface.
It is suitably about 20 to 70 ° as measured by a SA rubber hardness meter.

The surface of the elastic layer preferably has a surface roughness Rz of 1 to 20 in consideration of the releasability of the toner.
It can be set according to the particle size and shape of the toner used. The resistance value of the developing roller 1A is preferably set to a volume resistivity of about 10 ³ to 10 ⁹ Ωcm including the conductive resin film.

When the developing roller 1A is an elastic roller,
It is preferable to use a metal thin plate having a thickness of about 0.1 mm for the toner regulating blade 7. In this case, the developing roller 1A is positioned at a position about 2 mm from the tip.
It is preferable that the bent portion be contacted so as to bite into the developing roller 1A with a linear pressure of about 20 g / cm.

According to this embodiment, since the contact developing method is used, the developing bias applied to the developing roller 1A is DC.
The voltage can be sufficiently developed by using only the voltage. Considering the leakage with the photosensitive drum, the contact developing method using only the DC voltage (contact D
C developing method) may be rather preferable.

Therefore, in this embodiment, a DC voltage of about -450 V is developed from the power supply 2 with respect to the electrostatic latent image (exposed portion potential VL = -100 V, unexposed portion potential VD = -700 V) on the photosensitive drum. The development was performed by applying the voltage to the roller 1A.

As for the toner collecting member, a metal toner collecting roller 8 was used in the same manner as in Example 1, and was used without contact with the developing roller 1A and the photosensitive drum 21. The voltage applied to the developing roller 1A is -450 V, and the DC component of the toner collecting roller 8 is 0 V, and f = 1.8 kHz.
By applying an AC bias of about z, Vpp = 2 kV,
The undeveloped toner on the developing roller 1A can be collected by the toner collecting roller 8 without contact.

The transfer residual toner on the photosensitive drum 21 is also replaced with a new electrostatic latent image (exposure portion potential VL = −10) on the photosensitive drum.
(0 V, unexposed portion potential VD = −700 V) and the electric field formed by the bias applied to the toner collecting roller 8 allow the toner to be collected by the toner collecting roller 8 in a non-contact manner.

As described above, even in the case of the contact developing method in which the developing roller is brought into contact with the photosensitive drum, it is possible to collect the toner remaining on the developing roller and the transfer residual toner on the photosensitive drum.

In the above description, the developing roller is a rubber elastic roller, but the developing roller is a JISA
A low-hardness sponge-like elastic layer having a hardness of about 30 to 60 ° is formed, and a general rubber such as silicone rubber, NBR rubber, EPDM rubber, and urethane rubber having a high JISA hardness of 50 to 80 ° is formed thereon. An elastic roller provided with an elastic layer is also possible, and a sufficient effect is achieved.

Embodiment 5 FIG. 12 is a sectional view showing a developing unit according to still another embodiment of the present invention.

In the present embodiment, as in the case of the fourth embodiment, the developing roller 1A made of an elastic roller was brought into contact with the photosensitive drum, and development was performed by the contact developing method. The transfer residual toner on the photosensitive drum is collected in a contact manner by contacting a toner collecting roller 8A made of an elastic roller with the photosensitive drum, as in the second embodiment.
The collection of the residual toner on the developing roller 1A is performed in the third embodiment.
In the same manner as described above, the toner collecting roller 8A was brought into contact with the developing roller 1A to perform the contact-type operation.

Also in this embodiment, since the contact developing method is used, Vdc = Vdc =
Only −450 V is applied, while a DC voltage of about Vc = + 200 V is applied from the power supply 11 to the toner collecting roller 8A, and the residual toner on the developing roller 1A is removed by an electric field formed by these potential differences. The toner was collected by the toner collecting roller 8A in a contact manner.

Further, a new electrostatic latent image on the photosensitive drum (exposed portion potential VL = −100 V, unexposed portion potential VD = −700)
By the action of an electric field formed by the potential V) and the potential of the bias applied to the toner collecting roller 8A, the transfer residual toner on the photosensitive drum 1 was collected by the toner collecting roller 8A in a contact manner.

Needless to say, the transfer residual toner on the photosensitive drum can be sufficiently collected only by electrically grounding the toner collecting roller 8A.

In this embodiment, as in Embodiment 4, in the case of the contact developing method in which the developing roller is brought into contact with the photosensitive drum, the toner with the developing residue on the developing roller and the transfer residue on the photosensitive drum are transferred by the toner collecting roller. The toner can be collected.

[0113]

As described above, according to the present invention,
A plurality of image forming units each having an image carrier and a non-magnetic one-component developing unit are installed along the transfer material conveying means, and the toner images obtained on the image carriers of each image forming unit are sequentially superimposed on the transfer material. In an image forming apparatus that performs transfer together, toner is taken in by a toner supply brush arranged in contact with one end of a toner flow path control member of each developing device, and when the supply brush is detached from the toner flow path control member by rotation of the supply brush. By elastic force,
The toner is ejected from the supply brush to form a cloud, and an electric field formed between the developing roller and the supply brush causes only the toner having a desired charge amount to be supplied to the development roller from the clouded toner. Since there is no toner supply due to contact with the developing roller and rubbing as in the case of the conventional toner supply roller arranged in contact with the developing roller, the toner stress accompanying the toner supply to the developing roller is reduced. It can be significantly reduced. In addition, since the toner having an appropriate charge amount is selectively supplied from the clouded toner, not only is it difficult to supply the uncharged toner or the inverted toner, but also the charge applied to the toner by the regulating blade is reduced. As a result, the contact pressure of the regulating blade can be reduced,
The load on the toner was further reduced.

Further, the undeveloped toner that has returned to the developing container without contributing to the development is electrostatically peeled off by the toner collecting roller disposed in non-contact with the developing roller, and is reliably returned to the toner storage section. Since the toner circulation path is formed in the developing container, it is possible to prevent the residual toner from repeatedly passing through the nip portion of the regulating blade, thereby preventing a continuous load from being applied to the toner. , The embedding of the external additive into the toner due to the toner was significantly suppressed, and the deterioration of the toner was prevented.

Further, the toner collecting roller can also collect the transfer residual toner on the photosensitive drum at a portion facing the photosensitive drum, so that a conventional dedicated cleaning mechanism for the photosensitive drum can be omitted. The size and cost of the entire forming apparatus can be reduced.

Therefore, according to the present invention, the load on the toner can be remarkably reduced, and a high-quality color image free from fog can be obtained for a long period of time. Further, the size and cost of the entire apparatus can be reduced. Became possible.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an image forming apparatus of the present invention.

FIG. 2 is a cross-sectional view illustrating a developing device in the image forming apparatus of FIG.

FIG. 3 is an explanatory diagram showing a toner supply brush installed in the developing device of FIG. 2 and fibers thereof.

FIG. 4 is a cross-sectional view showing an example of a state of a cross section of a conductive fiber among the fibers of FIG.

FIG. 5 is a conceptual diagram showing a direction in which toner circulates in the developing device of FIG. 2;

FIG. 6 is an explanatory diagram illustrating a method of supplying toner to a developing roller by a toner supply brush in the developing device of FIG. 2;

7 is an explanatory diagram illustrating a configuration example of a bias used for toner supply and development in the image forming apparatus in FIG. 1;

8 is an explanatory diagram illustrating a configuration example of a bias used for collecting the remaining toner after development and collecting the remaining toner after transfer in the image forming apparatus of FIG. 1;

FIG. 9 is a cross-sectional view illustrating a developing device according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a developing device according to still another embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a developing device according to still another embodiment of the present invention.

FIG. 12 is a cross-sectional view illustrating a developing device according to still another embodiment of the present invention.

FIG. 13 is a schematic view showing a conventional image forming apparatus.

14 is a cross-sectional view illustrating a developing device in the image forming apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1A Developing roller 2 Power supply for developing bias 3 Developing container 4 Toner supply brush 5 Toner flow path control member 6 Power supply for toner supply brush 7 Restriction blade 8 Toner collection roller 9 Scraper 10 Stirring member 11 Photosensitive drum 12 Partition member 24 Developing device

Claims (7)

[Claims] A plurality of image forming units are provided along a transfer material conveying unit. Each of the image forming units includes an image carrier on which an electrostatic latent image is formed, and a static image formed on the image carrier. A developing device that develops the electrostatic latent image using a non-magnetic one-component developer,
An image forming apparatus for sequentially transferring and superimposing a visible image obtained by the development in each of the image forming units on a transfer material, wherein the developing device includes: a developing container containing a non-magnetic one-component developer; A rotating developer carrier that is disposed opposite to the image carrier at the opening of the container, a power source that applies a voltage to the developer carrier, and a developer carrier that rotates with respect to the rotation direction of the developer carrier. An upstream side of a developing unit in which a body and an image carrier are opposed to each other, a rotating developer supply member disposed in non-contact with the developer carrier, and A developer flow path control member arranged at one end thereof in contact with the developer supply member, and a developer flow path control member disposed at an upstream side of a facing portion between the developer supply member and the developer supply member. A power supply for applying voltage,
With respect to the rotation direction of the developer carrier, a developer regulating unit disposed in contact with the developer carrier upstream of the developing unit and downstream of an arrangement position of the developer flow path control member, A developer collection unit disposed on the downstream side of the developing unit with respect to the rotation direction of the developer carrier and opposed to the developer carrier and the image carrier; and a power supply for applying a voltage to the developer collection unit. Wherein the developer collecting means electrostatically removes and collects the undeveloped developer on the developer carrier and the untransferred developer on the image carrier. Forming equipment. 2. The image forming apparatus according to claim 1, wherein the developer collecting unit includes a developer collecting roller that electrostatically removes and collects the remaining developer and the remaining transfer developer. 3. The image forming apparatus according to claim 2, wherein the developer collection roller is a metal roller, and is disposed so as to face the developer carrier and the image carrier in a non-contact manner. 4. The image forming apparatus according to claim 2, wherein said developer collecting roller is formed of an elastic roller, and is disposed in contact with and opposed to at least one of said developer carrier and said image carrier. 5. The image forming apparatus according to claim 3, wherein said developer carrier is made of a metal roller, and is arranged so as to face said image carrier in a non-contact manner. 6. The image forming apparatus according to claim 3, wherein said developer carrying member comprises an elastic roller, and is arranged so as to be in contact with and opposed to said image carrying member. 7. The developer collection device according to claim 2, wherein the developer collection unit includes a scraper that contacts a surface of the developer collection roller and removes the developer collected in the developer collection row. An image forming apparatus according to claim 1.