JP2000089550A - Developing device and image forming device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device which stirs toner supplied into a developer container, sufficiently mixes the toner and developer, and enables the efficient contact of the toner with carrier, thereby preventing partial transfer omission, white fog on an image, and toner scatter in the device, and an image forming device provided with the developing device. SOLUTION: In this developing device 9 where the non-magnetic toner is supplied into the developer container 8 via a supply port 16 provided in the developer container 8 for storing the developer containing the non-magnetic toner and the magnetic carrier and a second stirring screw 12, as a freely rotating screw body, for stirring the developer in the developer container 8 and carrying it to a specific position is provided, a magnet 17 which is disposed near the second screw 12 and generates a magnetic field is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device in which a non-magnetic toner is supplied into a developer container containing a developer containing a non-magnetic toner and a magnetic carrier, and an image forming apparatus having the developing device. Things.

[0002]

2. Description of the Related Art With respect to a conventional example of such an image forming apparatus,
This will be described with reference to FIGS.

In such an image forming apparatus, a primary charger 121 uniformly charges a photosensitive drum 104, which is a rotatable rotatable latent image carrier, and a light emitting element 122 such as a laser emits image information. The photosensitive drum 104 is exposed by irradiating light modulated according to a signal onto the photosensitive drum 104 to form an electrostatic latent image according to the image information. The electrostatic latent image is provided with a non-magnetic toner by the developing device 109 and is visualized as a toner image. Next, the transfer charger 123 transfers the visible image to the transfer paper 124 transported by the transfer paper transport sheet 127, and the fixing device 125 fixes the visible image to the transfer paper 124 to which the visible image has been transferred. A permanent image is obtained by performing the processing. The transfer residual toner on the photosensitive drum 104 is removed by the cleaning device 126.

Next, the developing device 109 will be described.

[0005] As shown in FIG. 5, the developing device 109 is disposed to face the photosensitive drum 104 as a latent image carrier, and includes a developer container 108, a developing sleeve 103 for carrying a developer, and a developing sleeve 103. The image forming apparatus includes a developer return member 101 that regulates the amount of developer in the developer reservoir 105 and a blade 102 that regulates the height of the developer on the developing sleeve 103.

The developer container 108 is divided into a developing chamber 113 and a stirring chamber 114 by a partition 106 whose inside extends in a vertical direction.
It is divided into and. The developing chamber 113 and the stirring chamber 114 contain a developer (two-component developer) containing two components of a non-magnetic toner (hereinafter, referred to as toner) and a magnetic carrier (hereinafter, referred to as carrier). The excess developer in the chamber 113 is collected in the stirring chamber 114 side.

The developing chamber 113 has an opening at a developing area facing the photosensitive drum 104, and the developing sleeve 103 is rotatably disposed so as to be partially exposed at the opening.

The developing sleeve 103 is made of a non-magnetic material, rotates during the developing operation in the direction of the arrow shown in FIG. 6, and has a magnet 110 fixed therein for generating a magnetic field.

A developing sleeve 103 containing a magnet 110 carries and transports a layer of a two-component developer whose thickness is regulated by a blade 102 from a developer reservoir 105 to a developing area. A developer is supplied to the photosensitive drum 104 to develop an electrostatic latent image formed on the photosensitive drum 104. or,
In order to improve the developing efficiency, a developing bias on which a direct current or an alternating electric field is superimposed is applied to the developing sleeve 103 from a power source 115 provided on the image forming apparatus main body side.

The developing sleeve 103 and the magnet 110
The developer supplied to the surface of the developing sleeve 103 by the stirring screws 111 and 112 according to the above configuration,
Holding in the state of a magnetic brush by the magnetic force of the magnet 110,
This is conveyed to a portion facing the photosensitive drum 104, that is, to a developing area based on the rotation of the developing sleeve 103.

The developer returning member 101 and the blade 1
No. 02 is designed to appropriately maintain the amount of the developer conveyed to the development area by cutting the magnetic brush.

More specifically, the magnet 110 is composed of five poles, and the developer stirred by the stirring screw 111 is supplied to the conveying magnetic pole (pumping pole) N2 for pumping.
And is conveyed to the developer reservoir 105 by the rotation of the developing sleeve 103. The amount of the developer carried on the developing sleeve 103 is sufficiently regulated by the transport magnetic pole (cut pole) S2 having a magnetic force of a certain level or more in order to restrain the developer in a certain amount by the developer return member 101 and restrain a stable amount of the developer. It is constrained and transported while forming a magnetic brush. Next, the magnetic brush is cut off by the blade 102, which is a spike height regulating member, to make the amount of developer appropriate, and the magnetic force of the transport magnetic pole Nl and the developing sleeve 103
Is transported to the developing area by the rotation of.

The developer after developing the electrostatic latent image on the photosensitive drum 104 in the developing area is transported from the developing area to the developing chamber 113 by the rotation of the magnetic developing sleeve 103 of the transport magnetic pole N3 (take-in pole). Is done. Here, the take-in pole N3 and the pumping pole N2 are the same pole, and a region (repulsion pole) where the magnetic force is almost 0 Gauss is provided between the two magnetic poles. As a result, the developer after developing the electrostatic latent image is stored in the developing chamber 113 without being confined by the pumping pole N2.

The developing chamber 113 and the stirring chamber 114 have a first stirring screw 111 and a second conveying screw 1 respectively.
12 are arranged.

The first stirring screw 111 conveys the developer from the back side to the front side, and is delivered to the stirring chamber 114 on the front side, and the second stirring screw 112 conveys the developer from the front side to the back side. Then, it is transferred to the developing chamber 113 again.

Toner consumed by developing the electrostatic latent image on the photosensitive drum 104 in the developing area is supplied from a toner replenisher (not shown), and is supplied from a toner replenishing port 116 near the stirring chamber 114. It is supplied into the developing device 109. The supplied toner is stirred and mixed with the developer in the developing device 109 by the second stirring screw 112 in the stirring chamber 114, and then sent to the developing chamber 113 to be used again for image formation.

Next, charging of the toner will be described.

The charging of the newly supplied toner is mainly performed by rubbing in the developer reservoir 105, stirring by the first stirring screw 111 in the developing chamber 113, and stirring by the second stirring screw 112 in the stirring chamber 114. With stirring.

The developing sleeve 10 is moved by the pumping pole N2.
The developer carried on 3 is conveyed to the developer reservoir 105 by the rotation of the developing sleeve 103, the amount of the developer is regulated to some extent by the developer return member 101, and is sufficiently restrained by the cut pole S2. That is, the developing sleeve 10
The developer carried on 3 is rubbed by the magnetic force of the cut pole S2 and the rotational force of the developing sleeve 103, and the surface of the toner and the carrier come into contact and receive friction. Since the toner is particles such as polyester or styrene acrylic in which a pigment is dispersed, the toner is charged by rubbing a magnetic material such as ferrite with a carrier coated with acryl, silicon resin, or the like. In this conventional example, since the polyester toner and the silicon resin-coated ferrite carrier are used, the toner is negatively charged and the carrier is positively charged.

The first stirring screw 111 and the second stirring screw 112 are provided with a plurality of fins on the shaft. These fins rotate together with the first stirring screw 111 and the second stirring screw 112 to stir the conveyed developer, and in this stirring process, the surfaces of the toner and the carrier come into contact with each other and receive friction. Is given.

[0021]

However, in such an image forming apparatus, if the image is continuously output, the toner in the developer is consumed in the developing area, and is sequentially replaced with the toner supplied from the toner replenisher. To go. At this time,
The replenished toner and the developer are mixed, but in the method of stirring the developer with a screw or the like as in the above-described conventional example, the toner and the developer having a particle size of several to several tens of microns are mixed. It is difficult to perform sufficient stirring. If the replenished toner and the developer are not sufficiently mixed, the replenished toner cannot all contact the carrier surface, and is rubbed only by the toner into the developer reservoir 105 and further into the development area. Some of the toner to be conveyed also exists.

When such a process is repeated, the toner in the developer may have a charge of about 0 or a positively charged toner, which may cause a white background fog on the image and scattering of the toner in the machine. There is.

Some of the replenished toner has formed aggregates by being left in the toner replenisher, and the aggregates are conveyed to the developing unit without being destroyed, and are developed on the photosensitive drum together with the general toner. Then, when transferring the toner image to the transfer material, there is a possibility that a gap is generated due to the presence of the aggregate between the transfer material and the photosensitive drum, and a missing image that is not partially transferred is generated.

In order to suppress these problems, the magnetic restraining force is increased in the developer reservoir 105 so that the toner is not uniformly mixed, and the toner is strongly compressed to break up the toner aggregates, and the toner and the carrier are not mixed. Can also be forcibly brought into contact. However, this also imposes an excessive load on the developer, which in turn promotes the deterioration of the developer, lowers the chargeability of the carrier with respect to the toner, and reduces the fluidity of the developer. This is not a preferable method because it tends to be disadvantageous to stirring.

Therefore, according to the present invention, the toner replenished in the developer container is loosened, and the toner and the developer are sufficiently mixed.
It is an object of the present invention to provide a developing device capable of causing toner to efficiently contact a carrier without partial transfer omission, fogging of a white background on an image, and scattering of toner inside a device, and an image forming apparatus including the developing device.

[0026]

According to the present application, the object is to provide a developer container containing a developer containing a non-magnetic toner and a magnetic carrier through a supply port provided in the developer container. A developing device to which non-magnetic toner is supplied,
In a developing device having a stirring means which is a rotatable screw body for stirring and transporting a developer in a developer container to a predetermined position, a developing device which is disposed near the stirring means and has a magnetic field generating means for generating a magnetic field. This is achieved by the invention of

Further, according to the present application, the above object is achieved in the first invention in that the magnetic field generating means is provided near the supply port, and
The present invention is also achieved by the second invention in which the agitating means is disposed downstream of the stirring means in the developer conveying direction.

Further, according to the present application, the above object is achieved by the third invention in the first invention or the second invention, wherein the magnetic field generating means has a magnetic flux density of 500 G or more and 3000 G or less. .

Further, according to the present application, the above object is achieved in the fourth invention in any one of the first invention to the third invention, wherein the magnetic field generating means is detachably held to the developer container. Is also achieved by

Further, according to the present application, the above object is achieved according to any one of the first to fourth inventions, wherein the magnetic field generating means is provided at a lower portion of the developer container and extracts the developer from the developer container. The invention is also achieved by the fifth invention, which is integrally formed with a plug for a discharge port.

Further, according to the present application, the above object is to provide an image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, which is provided with a developing device of the first invention. The invention is also achieved by the invention of (1).

Further, according to the present application, the above object is achieved according to the sixth invention in that the magnetic field generating means is disposed near the supply port and downstream of the stirring means in the developer conveying direction. The invention is also achieved by the invention of (1).

According to the present application, the above object is also attained by the eighth invention in which, in the sixth or seventh invention, the magnetic field generating means has a magnetic flux density of 500 G or more and 3000 G or less. .

Further, according to the present application, the above object is attained in any one of the sixth to eighth inventions in that the magnetic field generating means is detachably held to the developer container. Is also achieved by

Further, according to the present application, the above object is achieved according to any one of the sixth to ninth inventions, wherein the magnetic field generating means is provided at a lower portion of the developer container and extracts the developer from the developer container. The present invention is also achieved by a tenth invention in which the plug is integrally formed with a plug for a discharge port.

That is, in the first invention according to the present application, the magnetic field generating means draws the magnetic carrier near the stirring means, and the stirring means stirs the drawn magnetic carrier and the supplied non-magnetic toner. .

In the second invention according to the present invention, the magnetic field generating means disposed near the supply port and downstream of the stirring means in the developer conveying direction is provided with a magnetic carrier near the stirring means. The stirring means stirs the attracted magnetic carrier and the supplied non-magnetic toner.

Further, according to the third invention of the present application, the magnetic field generating means having a magnetic flux density of 500 G or more and 3000 G or less draws the magnetic carrier near the stirring means, and the stirring means supplies the magnetic carrier with the drawn magnetic carrier. The obtained non-magnetic toner is stirred.

In the fourth invention according to the present application, the magnetic field generating means detachably held in the developer container draws the magnetic carrier near the stirring means, and the magnetic carrier drawn by the stirring means. And the supplied non-magnetic toner.

Further, in the fifth invention according to the present application, the magnetic field generating means integrally formed with the insertion plug draws the magnetic carrier near the stirring means, and the magnetic carrier is drawn by the stirring means. And the supplied non-magnetic toner.

In the sixth invention according to the present application, the magnetic field generating means draws the magnetic carrier near the stirring means, and the stirring means stirs the drawn magnetic carrier and the supplied non-magnetic toner. .

Further, according to the seventh invention of the present application, the magnetic field generating means disposed near the supply port and downstream of the stirring means in the developer conveying direction includes a magnetic carrier near the stirring means. The stirring means stirs the attracted magnetic carrier and the supplied non-magnetic toner.

According to the eighth aspect of the present invention, the magnetic field generating means having a magnetic flux density of 500 G or more and 3000 G or less draws the magnetic carrier near the stirring means, and the stirring means supplies the magnetic carrier with the drawn magnetic carrier. The obtained non-magnetic toner is stirred.

Further, according to the ninth invention of the present application, the magnetic field generating means detachably attached to the developer container draws the magnetic carrier near the stirring means, and the magnetic carrier drawn by the stirring means. And the supplied non-magnetic toner.

In the tenth invention according to the present application, the magnetic field generating means integrated with the insertion plug draws the magnetic carrier near the stirring means, and the magnetic carrier is drawn by the stirring means. And the supplied non-magnetic toner.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(First Embodiment) First, a first embodiment of the present invention will be described. Note that the configurations of the image forming apparatus and the developing device are not necessarily limited to the present embodiment.

FIG. 1 is a schematic sectional view showing a schematic configuration of an image forming apparatus according to this embodiment.

In this image forming apparatus, as shown in FIG. 1, a photosensitive drum 4 as a drum-shaped latent image carrier on which an electrostatic latent image is formed on an outer peripheral surface, and an outer peripheral surface of the photosensitive drum 4 are formed. A primary charger 21 for charging to a specified potential, a light emitting element 22 for forming an electrostatic latent image on the outer peripheral surface charged to a specified potential by exposure, and visualizing the electrostatic latent image with a developer Developing device 9 and a transfer material 24 serving as a sheet-shaped recording medium for transferring a visible image (visible image) formed on the outer peripheral surface.
Roller-like transfer charger 24 for transferring the image to fixing device 22
And

Next, the operation of the entire image forming apparatus will be described with reference to FIG.

In such an image forming apparatus, the primary charger 21 uniformly charges the photosensitive drum 4 which is a rotatable rotatable latent image carrier, and the information is transmitted by a light emitting element 22 such as a laser. An electrostatic latent image is formed by exposing with light modulated according to a signal. The electrostatic latent image is provided with a non-magnetic toner by the developing device 9 and is visualized as a toner image. Next, after the transfer charger 23 transfers the visible image to the transfer material 24 conveyed by the transfer paper conveyance sheet 27, the fixing device 25 performs a fixing process on the transfer material 24 to which the visible image has been transferred. To obtain a permanent image. The transfer residual toner on the photosensitive drum 4 is removed by the cleaning device 26.

FIG. 2 is a schematic sectional view showing a schematic configuration of the developing device 9.

As shown in FIG. 2, the developing device 9 is arranged to face the photosensitive drum 4 as a latent image carrier, and carries the developer container 8 and the developer in the developer container 8. The image forming apparatus includes a developing sleeve 3, a developer returning member 1 for regulating the amount of the developer in the developer reservoir 5, and a blade 2 for regulating the height of the developer carried on the developing sleeve 3.

The developer container 8 is divided into a developing chamber 13 and a stirring chamber 14 by a partition 6 extending in the vertical direction. The developing chamber 13 and the stirring chamber 14 contain a developer (two-component developer) containing a non-magnetic toner (hereinafter, referred to as a toner) and a magnetic carrier (hereinafter, referred to as a carrier). The excess developer is supplied to the stirring chamber 14.
It is to be collected by the side.

The developing chamber 13 and the stirring chamber 14 are respectively provided with a first stirring screw 11 (hereinafter, referred to as a conveying screw 11) and a second stirring screw 12 (hereinafter, referred to as a stirring means).
A second transport screw 12) is disposed.

The developing chamber 13 has an opening in a developing area facing the photosensitive drum 4, and the developing sleeve 3 is rotatably arranged so as to be partially exposed in the opening.

The developing sleeve 3 is made of a non-magnetic material, and a magnet 10 for generating a magnetic field is fixedly disposed inside the developing sleeve 3, and rotates in a direction indicated by an arrow in FIG. 2 during a developing operation.

Developing sleeve 3 containing magnet 10
Transports and transports the layer of the two-component developer, the layer thickness of which is regulated by the blade 2, from the developer reservoir 5 to the developing area, and supplies the toner to the photosensitive drum 4 in the developing area facing the photosensitive drum 4. 4 is developed. In order to improve the developing efficiency, a developing bias in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve 3 from a power supply 15 provided on the image forming apparatus main body side.

The developer supplied to the surface of the developing sleeve 3 by the stirring screw 11 and the stirring screw 12 is applied to the developing sleeve 3 and the magnet 10.
The developer is conveyed to a portion facing the photosensitive drum 4, that is, a developing area based on the rotation of the developing sleeve 3. Further, the developer returning member 1 and the blade 2 maintain the amount of the developer transported to the developing area by cutting the magnetic brush.

More specifically, the magnet 10 is composed of five poles, and the developer stirred by the stirring screw 11 is restrained on the developing sleeve 3 by the magnetic force of the transport magnetic pole (pumping pole) N2 for pumping. The developer is conveyed to the developer reservoir 5 by the rotation of the developing sleeve 3. The amount of the developer carried on the developing sleeve 3 is regulated to some extent by the developer return member 1, and in order to restrain a stable amount of the developer, a transport magnetic pole (cut pole) S having a magnetic force of a predetermined level or more is used.
2 and is conveyed while forming a magnetic brush. Next, the developer is cut by a magnetic brush with a blade 2 serving as a spike height regulating member to make the amount of the developer appropriate, and while being carried on the developing sleeve 3 by the magnetic force of the transport magnetic pole Nl, the developing sleeve 3 is rotated. It is transported to the development area.

After developing the electrostatic latent image on the photosensitive drum 4 in the developing area, the developer is transferred to the transport magnetic pole N3 (take-in pole).
Is transported from the development area to the development chamber 13 by the magnetic force of the rotation of the development sleeve 3. Here, the take-in pole N3 and the pumping pole N2 have the same polarity, and a region (repulsion pole) where the magnetic force is almost 0 Gauss is provided between the two magnetic poles. As a result, the developer after developing the electrostatic latent image is stored in the developing chamber 13 without being confined by the pumping pole N2.

The toner consumed during image formation is supplied from a toner supply unit (not shown) during image formation.
The newly replenished toner is mixed and stirred with the developer in the stirring chamber 14 by the stirring screw 12, and is conveyed by the rotation of the developing sleeve 3 while being constrained by the cut pole N2. The inside toner and the carrier are rubbed. In this way, charging of the supplied toner is performed.

Next, a characteristic portion of the present embodiment will be described in more detail with reference to FIG.

In the image forming apparatus according to this embodiment, a magnet having a magnetic flux density of 1000 G is provided on the side of the stirring chamber 14 in FIG. 17 is arranged.

With such a configuration, as shown in FIG. 3, the developer is conveyed to the developer container 8 side by the magnetic force of the magnet 17 in the process of being transported from the supply port 16 (front side) to the back side. It is attracted to form the developer spikes 18.

Generally, the toner 19 immediately after being replenished from the replenishing port 16 is often conveyed from the near side to the back side while floating on the conveyed developer. By forming the retaining ears, as shown in FIG. 3, the transported toner 19 is pressed against the developer ears 18, the aggregates of the toner collapse, and the lump of toner that does not form the aggregates is formed. Are also scattered and mixed. Almost at the same time as the process, the developer forming the spikes 18 by the magnetic force of the magnet 17 is separated from the magnet 17 by the blades of the screw and transported to the back side together with the dispersed toner.

Since the replenishment toner in which the aggregates are broken and dispersed is dispersed, the toner can be sufficiently mixed and stirred with only the screw after that and can be brought into contact with the carrier.

With conventional stirring using only a screw, the developer can be moved only on a macroscopic scale, and it is difficult to quickly loosen a state where the toner of about several microns is solidified. The chance of contact between the toner and the carrier surface is small, and the rubbing between the toners increases,
The charge of the toner is non-uniform and the charge distribution becomes broad.

According to the constitution of the present invention, the aggregates and lumps of the toner are reduced, the toner is uniformly dispersed in the developer, and the chance of the toner contacting the carrier surface is increased. Then, the distribution of the charge of the toner becomes sharp. There is no partial transfer omission.

According to the experiments by the inventors, if the magnetic flux density of the magnetic field generating means is 500 G or more, the effect of removing the toner is obtained, and the effect is large although the magnetic flux density is large. However, if the magnetic flux density is too large, the load applied to the transport screw becomes large, and if it is 3000 G or more, there arises a problem that the noise device becomes large. Therefore, 500 to 3000 G is preferable.

Therefore, according to the present embodiment, the supply port 16
, And a magnet 17 having a magnetic flux density of 500 G or more and 3000 G or less, which is disposed downstream of the screw 12 in the developer transport direction, draws the carrier near the screw 12 and is supplied with the carrier to which the screw 12 is drawn. Since the toner and the toner are agitated, the toner supplied into the developer container 8 is loosened and the developer container 8 is stirred.
By sufficiently agitating the developer inside, the carrier and the toner come into efficient contact with each other, whereby partial transfer omission of an image, fogging of a white background on an image, and scattering of non-magnetic toner can be prevented.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

In general, when a developer is used for a long time, the developer deteriorates, the ability to impart charge to the carrier is reduced, or the fluidity of the developer is reduced, so that the image quality is lower than in the initial state. In such a case, an operation of replacing the developer with a new developer is generally performed. For replacement work, for example, a hole for draining the agent is provided on the bottom surface of the container in the developer transfer path, a cap-type stopper is used during normal use, and the stopper is removed when the developer is replaced, and the transfer screw is fixed. A method is employed in which the developer is dropped from the holes by transporting the agent for a while.

However, if the magnetic field generating means is arranged near the developer conveying path as in the first embodiment, the developer is retained by the magnetic field generating means and does not come out at the time of replacement but remains. There is a problem.

In this embodiment, in order to solve these problems, the magnetic field generating means is detachably attached to the developer container. That is, when a service person or the like replaces the developer, the magnet can be removed to remove the developer.

Further, as shown in FIG. 4, the operation of the service person is simplified by forming the magnet 17 integrally with the plug 20 for removing the agent.

Therefore, according to the present embodiment, the magnet 17 which is integrally formed with the stopper 20 and is detachably held to the developer container 8 draws the carrier to the vicinity of the screw 12, and the screw 12 is drawn. Since the supplied carrier and the supplied toner are agitated, the supplied toner is loosened in the developer container 8 and sufficiently agitated with the developer in the developer container 8, so that the carrier and the toner become efficient. By making good contact, it is possible to prevent partial transfer omission of an image, fogging of a white background on the image, and scattering of non-magnetic toner, and it is possible to replace the developer in the developer container 8, and to perform development. The old developer can be easily removed when the developer in the developer container 8 is replaced.

[0078]

As described above, according to the first aspect of the present invention, the magnetic field generating means draws the magnetic carrier near the stirring means, and the magnetic means supplies the magnetic carrier drawn by the stirring means. The non-magnetic toner is agitated with the non-magnetic toner, so the non-magnetic toner supplied in the developer container is loosened and sufficiently stirred with the developer in the developer container, so that the magnetic carrier and the non-magnetic toner are efficiently separated. The contact makes it possible to prevent partial transfer omission of the image, fogging of the image on a white background, and scattering of non-magnetic toner.

According to the second invention of the present application,
Magnetic field generating means disposed near the supply port and downstream of the stirring means in the developer conveying direction draws the magnetic carrier near the stirring means, and the magnetic carrier drawn by the stirring means and the supplied non-magnetic toner. Is stirred so that the non-magnetic toner supplied into the developer container is loosened and sufficiently stirred with the developer in the developer container so that the magnetic carrier and the non-magnetic toner come into efficient contact with each other. As a result, partial transfer omission of an image, fogging of a white background on an image, and scattering of non-magnetic toner can be prevented.

Further, according to the third invention of the present application, the magnetic field generating means having a magnetic flux density of 500 G or more and 3000 G or less draws the magnetic carrier near the stirring means, and the stirring means supplies the magnetic carrier drawn. The non-magnetic toner is agitated with the non-magnetic toner, so the non-magnetic toner supplied to the developer container is loosened and sufficiently stirred with the developer in the developer container, so that the magnetic carrier and the non-magnetic toner are efficiently separated. By making good contact, it is possible to prevent partial transfer omission of an image, fogging of a white background on an image, and scattering of non-magnetic toner.

According to the fourth invention of the present application,
Since the magnetic field generating means detachably held with the developer container draws the magnetic carrier near the stirring means, and the stirring means stirs the drawn magnetic carrier and the supplied non-magnetic toner. The non-magnetic toner supplied in the developer container is loosened and sufficiently stirred with the developer in the developer container so that the magnetic carrier and the non-magnetic toner come into contact with each other efficiently, so that the image is partially transferred. ,
It is possible to prevent a white background fog on the image and the scattering of the non-magnetic toner, and it is possible to replace the developer in the developer container.

Further, according to the fifth aspect of the present invention, the magnetic field generating means integrally formed with the insertion plug draws the magnetic carrier near the stirring means, and the magnetic carrier with the stirring means draws the magnetic carrier. Since the supplied non-magnetic toner is agitated, the supplied non-magnetic toner is loosened in the developer container, sufficiently stirred with the developer in the developer container, and the magnetic carrier and the non-magnetic toner are mixed. Makes it possible to prevent the partial transfer of the image, the fogging of the white background on the image, and the scattering of the non-magnetic toner, and to remove the old developer when replacing the developer in the developer container. It can be easily removed.

According to the sixth invention of the present application,
Since the magnetic field generating means attracts the magnetic carrier to the vicinity of the stirring means and the stirring means agitates the attracted magnetic carrier and the supplied non-magnetic toner, the non-magnetic toner supplied to the developer container The toner is sufficiently agitated with the developer in the developer container so that the magnetic carrier and the non-magnetic toner come into efficient contact with each other. Scattering can be prevented.

Further, according to the seventh invention of the present application, the magnetic field generating means disposed near the supply port and downstream of the stirring means in the developer conveying direction transfers the magnetic carrier near the stirring means. Since the attracting and agitating means agitates the attracted magnetic carrier and the supplied non-magnetic toner, the supplied non-magnetic toner is loosened in the developer container, and the developer in the developer container is removed. By sufficiently stirring the magnetic carrier and the non-magnetic toner to come into efficient contact with each other, it is possible to prevent partial transfer omission of the image, fogging of the image on a white background, and scattering of the non-magnetic toner.

According to the eighth invention of the present application,
The magnetic field generating means having a magnetic flux density of 500 G or more and 3000 G or less draws the magnetic carrier near the stirring means, and the stirring means stirs the drawn magnetic carrier and the supplied non-magnetic toner. The non-magnetic toner supplied in the container is loosened and sufficiently stirred with the developer in the developer container so that the magnetic carrier and the non-magnetic toner come into contact with each other efficiently, resulting in a partial transfer omission of the image and an image. The above-mentioned white background fogging and scattering of non-magnetic toner can be prevented.

Further, according to the ninth aspect of the present invention, the magnetic field generating means detachably held in the developer container draws the magnetic carrier near the stirring means, and the magnetic carrier is brought into contact with the magnetic carrier drawn by the stirring means. Since the supplied non-magnetic toner is agitated, the supplied non-magnetic toner is loosened in the developer container, sufficiently stirred with the developer in the developer container, and the magnetic carrier and the non-magnetic toner are mixed. Makes it possible to prevent partial transfer omission of an image, fogging of a white background on an image, scattering of non-magnetic toner, and replacement of a developer in a developer container. .

According to the tenth aspect of the present invention,
The magnetic field generating means integrally formed with the insertion plug draws the magnetic carrier near the stirring means, and the stirring means stirs the drawn magnetic carrier and the supplied non-magnetic toner. The non-magnetic toner supplied in the developer container is loosened and sufficiently stirred with the developer in the developer container so that the magnetic carrier and the non-magnetic toner come into contact with each other efficiently, so that the image is partially transferred. In addition, it is possible to prevent white background fogging on the image and scattering of the non-magnetic toner, and it is possible to easily remove old developer when replacing the developer in the developer container.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a schematic configuration of a developing device provided in the image forming apparatus of FIG.

FIG. 3 is a top view of the developing device of FIG. 2;

FIG. 4 is a schematic cross-sectional view illustrating a schematic configuration of a developing device according to a second embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view illustrating a schematic configuration of a conventional image forming apparatus.

6 is a schematic sectional view showing a schematic configuration of a developing device provided in the image forming apparatus of FIG.

[Explanation of symbols]

 Reference Signs List 8 developer container 9 developing device 12 second transport screw (stirring means) 16 supply port (supply port) 17 magnet (magnetic field generating means) 20 stopper (plug stopper)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takao Ogata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kazuhiro Hasegawa 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo In-house F term (reference) 2H031 AB02 AC08 AC14 AC19 AC20 AC38 AD00 AD11 BA04 BB01 CA11 FA00 2H077 AA01 AA35 AB02 AB18 AC00 AD02 AD06 AD13 AD36 AE06 BA08 CA11 EA03 FA19 GA01

Claims (10)

[Claims] 1. A developing device in which a non-magnetic toner is supplied into a developer container through a supply port provided in a developer container containing a developer containing a non-magnetic toner and a magnetic carrier. A developing device having a stirring means which is a rotatable screw body for stirring and transporting a developer in a developer container to a predetermined position, further comprising a magnetic field generating means disposed near the stirring means to generate a magnetic field. Developing device. 2. The magnetic field generating means is provided near the supply port, and
The developing device according to claim 1, wherein the developing device is provided downstream of the stirring means in a developer conveying direction. 3. The developing device according to claim 1, wherein the magnetic field generating means has a magnetic flux density of 500 G or more and 3000 G or less. 4. The developing device according to claim 1, wherein the magnetic field generating means is detachably held in the developer container. 5. The magnetic field generating means is integrally formed with a plug provided at a lower portion of the developer container for an outlet for extracting the developer from the developer container. The developing device according to claim 4. 6. An image forming apparatus for recording an image formed by a series of image forming processes on a recording medium,
An image forming apparatus comprising the developing device according to claim 1. 7. A magnetic field generating means is provided near the supply port, and
7. The image forming apparatus according to claim 6, wherein the image forming apparatus is provided downstream of the stirring means in the developer conveying direction. 8. The image forming apparatus according to claim 6, wherein the magnetic field generating means has a magnetic flux density of 500 G or more and 3000 G or less. 9. The image forming apparatus according to claim 6, wherein the magnetic field generating unit is detachably held on the developer container. 10. The magnetic field generating means is integrally formed with a plug provided at a lower portion of the developer container and for an outlet for extracting the developer from the developer container. The image forming apparatus according to claim 9.