JPH11143196A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of prolonging the developer replacing interval, and simplifying the developer replacing operation, while maintaining optimization for the size of the developing device and the device main body. SOLUTION: This device is provided with the developer containing unit 300 constituted as a unit of a detached body from developing means 10 arranged on a detached position. This developer containing unit 300 is, consisting of toner and developer contain-mixing means 400, and recovered developer containing means 500, the toner and developer contain-mixing means 400 connected with developing means 10 by a feeding pipe 111 as a feeding path, and the recovered developer containing means 500 are connected with the developing means 10 and the recovering pipe 121 as the discharging path. Then, transferring of the developer in between this developer containing unit 300 and the developing means 10 is performed by developer transferring means 200.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, a developing unit having a developing sleeve provided opposite to a photoreceptor as an electrostatic latent image carrier is replenished with a storing portion for storing a developer and toner. Many have tanks. However, in this type of device, the developer storage unit and the toner tank are integrally formed with the unitized developing means, so that the developing device becomes large, the device configuration becomes complicated, and the operability at the time of device maintenance is improved. There is a problem that is reduced.

Therefore, it has been proposed to provide a toner tank separately from a developing means having a developing sleeve and supply toner from the toner tank. As a specific method, a method is used in which the toner storage section and the developing means are connected by a pipe, and the toner is supplied to the developing means by transferring the toner to the developing means by a coil screw provided inside the pipe. A toner storage container is provided at an upper position, and toner is supplied from the toner storage container to the developing unit mainly by gravity.

The charging ability of a two-component developer deteriorates with time due to fatigue, crushing, toner filming, and the like of a carrier. The durability life of the two-component developer varies depending on the toner used and the developing device. Has to be replaced. This replacement requires manual operation, disassembly of the developing device, removal of the developer, refilling, and re-assembly with machine adjustment. Since the developer sometimes scatters easily, consideration must be given to the working environment.

[0005] Therefore, in order to extend the interval of the replacement operation quickly, it is effective to increase the amount of developer stored in the developing device.

[0006]

However, in the above-described system in which the toner is transferred to the developing means by the coil screw, the position of the toner storage section is limited because the coil screw can be arranged almost linearly, and the transport distance is reduced. There is a problem that a long driving time requires a strong driving force. Further, the method of supplying the toner from the storage container to the developing unit by gravity also has a problem that the installation position of the toner storage unit is further limited.

In order to extend the interval of the developer replacement operation, it is necessary to increase the amount of developer stored in the developing device.
As the size of the developing device increases, the size of the image forming apparatus itself becomes larger, the structure of the device becomes more complicated, the operability during maintenance of the device decreases, and the cost increases. was there.

The present invention solves the above-mentioned conventional problems,
It is an object of the present invention to provide an image forming apparatus capable of prolonging a developer replacement interval and simplifying a developer replacement operation while maintaining appropriate sizes of a developing device and a device main body.

[0009]

In order to achieve the above object, the present invention relates to a latent image bearing member which is arranged around a latent image bearing member and which is provided with a developer comprising a mixture of toner and carrier. In an image forming apparatus having a developing unit for visualizing an electrostatic latent image formed thereon, a storage unit that is separately disposed in a different place from the developing unit and stores the toner and the carrier, A developer mixing means for adjusting a mixing ratio of the toner and the carrier stored in the storage means; and a developer transfer means for transferring the developer prepared by the developer mixing means to the developing means. It is characterized by:

The present invention is effective when the developing means has a developer inlet for receiving the developer prepared by the developer preparing means and a developer outlet for discharging a predetermined amount or more of the developer. It is.

Further, the present invention is effective when the storage means and the developer preparation means are provided in one unit as a developer storage and preparation unit. Still further, the present invention is effective when the storage means has a toner storage section and a carrier storage section independently of each other, and the toner storage section and the carrier storage section are provided with supply means respectively. is there.

Still further, according to the present invention, the developer mixing means is provided in the developer accommodating / mixing unit and includes a partition member for separating supplied toner and a carrier, and a carrier supply hole formed in the partition member. Is effective.

Further, the present invention is effective when a developer transferring means for transferring the prepared developer to the developing means is provided below the developer preparing means. Furthermore, the present invention is effective when the developer transfer means includes a powder pump.

Furthermore, the present invention further comprises a collected developer transferring means for transferring the remaining surplus developer applied to the development from the developing means to a collected developer accommodating means, wherein the collected developer transferring means is provided. It is effective if a powder pump is provided at the developer outlet.

Further, the present invention is effective when the toner storage section is formed in a container which can be detachably mounted to the storage means.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the configuration of an image forming apparatus according to the present invention and a developing unit.

In FIG. 1, reference numeral 1 denotes photosensitive drums 1 and 10 serving as latent image bearing members, and developing means. In the present embodiment, a two-component magnetic brush developing system is used.
The photosensitive drum 1 is charged and exposed by a conventionally known electrophotographic image forming process to form an electrostatic latent image,
This electrostatic latent image is formed into a toner image (developed image) by the developing unit 10. The developing means 10 includes a developing sleeve 100 disposed opposite to the photosensitive drum 1 and the developing sleeve 1.
It has a first screw 110 and a second screw 112 as a developer supply member arranged in parallel with 00.

The image forming apparatus is provided with a developer accommodating unit 300 which is configured as a unit separate from the developing means 10 according to the present invention and is disposed at a different position. The developer storage unit 300 includes a toner and developer storage / mixing unit 400 and a collected developer storage unit 50.
And toner and developer storage / mixing means 4
Reference numeral 00 is connected to the developing means 10 by a supply pipe 111 serving as a supply path, and the collected developer accommodating means 500 is connected to the developing means 10 by a collection pipe 121 serving as a discharge path. The transfer of the developer between the developer accommodating unit 300 and the developing means 10 is performed by a toner and developer transferring means 200 which will be described later in detail.

The toner in the developer accommodating unit 300 and the developer transferred from the developer accommodating / mixing means 400 to the developing means 10 via the supply pipe 111 are supplied to the first screw 110.
And the second screw 112 causes the developing sleeve 100
And transferred to the entire surface. Then, the developer is formed into an optimum developer layer thickness by a doctor blade 130 as a developer regulating member and is used for development. The surplus developer is circulated again inside the developing unit 10 by the first screw 110 and the second screw 112.

The replenishing toner 601 of the developer transferred to the developing unit 10 is consumed during image formation, but the carrier 401 remains in the developing unit 10. Therefore, as the number of copies or prints increases, the developing means 1
Since the amount of carriers increases within 0, a new developer is supplied. By supplying the developer, the increased amount of the excess developer is guided to a collecting screw 120 as a developer collecting member, passing through a regulating member 150 provided in a part of the developing container 140. Then, the surplus developer is sent to the collection / development storage unit 500 via the collection tube 121.

The regulating member 150 is for quantifying the amount of developer contained in the developing means 10. When the amount of surplus developer increases as described above, the developer is removed from the collecting screw 120. When the amount of the developer is small, the developer is stopped on the first screw 110 side.
The shape and the mounting position are set. Although the regulating member 150 of this embodiment is formed integrally with the developing container 140, it may be attached to the developing container 140 as a separate component.

Referring to FIG. 2 and FIG.
Both ends in the width direction of the developing sleeve 100 are closed by side plates, and a part of the side plate 101 on one end side is a first screw 11.
In order to form a circular hole for accommodating the screw portion of the first screw 110 and the collecting screw 120, the screw portions of the first screw 110 and the collecting screw 120 are respectively formed in the circular hole formed in the cylindrical portion. Mated. Further, the end shafts of the respective screw portions are supported by lid members 101a and 101b for closing the circular holes, respectively.

A developer inlet 111a and a developer outlet 121a are provided in the middle of each of the circular holes in a direction perpendicular to the circular holes. These are connected by a supply pipe 111 as a supply path and a recovery pipe 121 as a discharge path.

FIG. 4 is a schematic sectional view showing another embodiment of the developing means. In FIG. 4, the developer transferred from the developer inlet 111a 'to the developing device is temporarily stored in the developer storage unit 116. The agent storage section 116 is provided with an agent supply roller 114 having a plurality of grooves formed on the surface thereof, and a leaf spring 115 serving as a lid is in contact with the roller. Then, a fixed amount of developer is stored in the groove of the agent supply roller 114, and when the agent supply roller 114 is rotated by a developer supply signal, the developer is supplied into the developing unit 10 '.

A stirring roller 1 is provided inside the developing means 10 '.
10 ′ and a paddle wheel 113 are provided,
A two-component developer composed of a toner and a carrier, which are agitated and mixed by the agitating roller 110 ′ and frictionally charged to opposite polarities, is pumped up by the paddle wheel 113.

At a position where the developer is pumped up by the paddle wheel 113, two developing sleeves 100 'are provided close to the photosensitive drum 1'. A doctor blade 130 'for regulating the thickness of the magnetic brush is provided at a position on the peripheral surface of the developing sleeve 100' before reaching the photosensitive drum 1 '. Also,
A rotatable transport screw 112 'is disposed above the stirring roller 110'.

Further, a developing container 14 is provided in the developing means 10 '.
0 ′ is provided with a regulating member 150 ′, and the developer exceeding the regulating member 150 ′ is collected by the collecting screw 12 ′.
It is led to 0 '. Then, the excess developer is collected in a collection tube 12.
It is sent to the collecting and developing storage means (not shown) via 1 '.

The developing means shown in FIG. 1 is suitable for an image forming apparatus which performs a developing process at a relatively middle speed or lower, whereas the developing means shown in FIG. 4 is suitable for an image forming apparatus having a middle speed or higher. ing.

FIG. 5 shows a toner and developer storing / transporting means 40.
FIG. 6 is a front cross-sectional view taken along the center line of FIG. 5 and 6, the toner and developer storing / mixing means 400 has a container 410,
To 0, two of the toner storage unit 411 and the carrier storage unit 412 are set.
It has two storage sections. A mounting member 413 for mounting a replenishment toner storage member 600 having a container 610 configured as a bottle, a bag, or the like above the toner storage portion 411.
Is provided.

The replenishing toner storage member 600 has a container 610 for storing the replenishing toner 601 therein, a base 611 having a part opened at an end thereof, and a slidable member with the base. Further, a shutter member 612 for opening and closing the base portion by rotating is provided.

When the replenishment toner storage member 600 is inserted into the attachment member 413 and then rotated, the shutter member 61 is rotated.
2 rotates, the base 611 is opened, and the replenishing toner 601 falls into the toner storage 411 by its own weight, and the toner storage 411 is filled with the toner.

When the replenishment toner storage member 600 is to be removed, these operations are reversed.
Is rotated to the opposite side, the base 611 is closed.
With the mechanism configured as described above, it is possible to reliably prevent the toner from scattering when the replenishment toner is replenished into the toner storage unit 411.

The toner storage section 411 is provided with a transfer screw 420 as a transfer member at a lower bottom thereof, and a stirring member 430 at an intermediate portion above the screw. A drive gear 441 is attached to one end of the transfer screw 420, and a powder pump unit 450 is attached to the other end. The transfer screw 420 and the stirring member 430 are the same as those in FIG.
As shown in the figure, the driving motor 440 is rotationally driven by a plurality of driving gears 441 connected thereto.

A supply roller 470 as a supply member, a leaf spring 471 as an amount regulating member in contact with the supply roller 470, and a seal member 4
72 are installed. The end of the supply roller 470 is drivingly connected to the driving gear 441 described above.

When the supply roller 470 is rotated, an excess amount of the carrier 401 held in the groove is scraped off by the leaf spring 471, and a constant amount of the carrier 401 is always supplied. The seal member 472 is made of sponge rubber or the like, seals a space between the partition plate 418 as a partition member provided between the supply roller 470 and the toner storage section 411, and prevents the carrier from scattering and falling. .

The supplied carrier 401 is separated from the partition plate 41.
8 is guided to the toner storage section 411 through a carrier supply hole 415 formed in a part of the toner supply section 8. Then, the toner storage section 41
1 and mixed with toner,
It is carried to the powder pump unit 450.

To replenish the carrier 401 into the carrier accommodating portion 412, the cover 417 is opened and the replenishing operation is performed through the opening 416. Since the mass of the carrier 401 is larger than that of the toner, the carrier 401 does not fly into the air at the time of the above-mentioned replenishing operation, and can be safely refilled.

As the powder pump unit 450, a single-shaft eccentric screw pump, which is conventionally known as a so-called Mohno pump, is used, and includes a rotor 451, a stator 452, and a holder 453. The rotor 451 is engaged with and connected to the transfer screw 420 and integrally moves.

The stator 452 is made of an elastic material such as a rubber material, surrounds the rotor 451, and is fixed by a holder 453. There is a gap of about 1 mm between the side surface of the stator 452 and the inner side surface of the holder 453,
This gap communicates with the developer discharge port. Holder 45
3 is provided with an air supply port 454 for blowing air from the air pump 460 into the developer passage into the gap. In addition, about 1 to 3 liters / minute of air is supplied from the air pump 460 to the powder pump unit 450 via the air pipe 461 and the air supply port 454.

The developer is promoted to be fluidized by blowing air, so that the developer can be more reliably transferred by the powder pump. The supply pipe 111 is connected to the tip of the holder 453, and the developer is transferred from the powder pump unit 450 to the developing unit 10 via the supply pipe 111.

In this embodiment, the powder pump unit 450 and the air pump 460 are configured to be driven separately and separately.
The control of the drive motor 440 and the air pump 460 is performed by turning off only the air pump 460 at the start of operation.
N, and after several seconds, the drive motor 440 is turned on.
At the time of stop, it is desirable to operate only the air pump for several seconds after the drive motor 440 is turned off. By controlling the driving in this way, the developer can be prevented from remaining in the supply pipe 111, and the transfer of the developer can be made more reliable.

As described above, the charging ability of a two-component developer deteriorates with time due to carrier fatigue, crushing, toner filming, and the like, and its durable life varies depending on the toner used and the developing device. , 50-130k
They have to be replaced at the rate of sheets / kg. This replacement operation must be performed by a professional service person, which allows the user to lose machine downtime during replacement,
They had to pay for the replacement.

In order to shorten the replacement work and time, there is also a method of replacing the entire developing device without replacing only the developer, but this method also replaces a part which can be used sufficiently. As a result, there is a problem that resources are wasted and a user's cost burden becomes enormous.

Therefore, in order to solve this problem, the present invention is configured to include a toner, developer storing / mixing unit 400 and a collected developer storing unit 500 which are independent and separate from the developing unit 10. Disassembly and reassembly of the developing means 10 at the time of replacement of the developer is not required, and not only the developer replacement can be performed with a simple operation, but also the developer replacement operation interval can be extended. It is.

The supply of the developer (the carrier 401 and the replenishing toner 601) to the developing means 10, 10 'is performed by the developer concentration detecting member 1 provided in a part of the developing means 10, 10'.
The control is performed by control means (not shown) such as 60 and 160 '.

The developer concentration detecting members 160 and 160 '
It comprises a conventionally known magnetic permeability sensor, and detects the developer concentration of the developer in the developing means. If the detected value is less than a predetermined value, the drive motor 440 and the air pump 460 in the developer accommodating / mixing means are driven, and the transfer screw 420, the supply roller 470 and the powder The developer is supplied by the pump unit 450. When the developer concentration exceeds a predetermined value, the supply of the developer is stopped.

By these controls, the developing means 10, 1
At 0 ', a developer having a constant developer concentration is always stored, and a stable developing process is guaranteed. Further, the developer concentration detecting members 160 and 160 ′ detect that the developer concentration is lower than a predetermined value, and when the developer concentration exceeds a predetermined number of times / time, the toner is stored in the toner storage unit 411. It determines that there is no such information, and issues a warning that can be understood by the operator to an operation unit or a display unit provided in a main body (not shown) such as a copying machine or a printer. Thus, toner supply and carrier supply to the developer accommodating / mixing device can be performed at an appropriate time.

The developer concentration detecting members 160 and 16
Instead of 0 ', it is also possible to detect the density of a toner image formed on a conventionally known photosensitive drum and perform the same supply control of the developer.

The mixing ratio of the carrier and the toner in the developer supplied to the developing means 10, 10 'is determined by the durable life of the developer used and the amount of the developer that can be stored in the developing device used.

If the durability life of the developer used is 120,
Assuming that the amount of developer that can be stored in the current fabrication device used is 1 kg at k sheets / kg, the developer is 0.008 g per copy / print (1 kg / 120 k sheets ≒ 0.0
(08 g / sheet). Also, the average toner consumption is 0.03 g / sheet (average toner consumption statistically determined based on the user's usage record).
The mixing ratio of the carrier and the toner in the developer supplied to the developing means is 1: 3.8 (0.008: 0.03０．０) by weight.
1: 3.8), and the volume ratio is 1: 18.9 because the specific gravity is 1.2 for the toner and 4.5 for the carrier.

The shapes of the transfer screw 420, the powder pump unit 450, and the supply roller 470, and the rotation ratio between the members are optimized so as to satisfy the mixing ratio. At this time, in the toner / developer storing / mixing means 400, it is convenient that the storage volume of the carrier 401 and the replenishing toner 601 is also set to a ratio satisfying the above-described relationship. Further, when it is desired to increase the replacement interval of the developer, the capacity of the carrier storage section 412 may be increased. Therefore, if a user who uses the image forming apparatus frequently uses a machine, if the storage amount of the developer is increased in advance, the replacement interval of the developer can be increased, thereby reducing the machine downtime of the user.

In the above-described embodiment, the transfer screw 420, the powder pump unit 450, and the supply roller 470 are driven by one drive motor 440 to simplify the structure of the apparatus. Needless to say, driving and controlling the 470 with an independent drive motor to supply and control the carrier does not violate the intent and purpose of the present invention.

Further, according to the method of the present invention, since the developing means 10 and 10 'are always replenished with a new developer, the influence of the deterioration of the developer over time is alleviated and the stability is improved. The quality is stable, and the image quality is high and stable.

When the supply amount of the carrier is increased or the supply interval is shortened, a fresh carrier is always supplied to the developing means, so that the change over time in the developing characteristics is reduced and the image quality over time is improved. Stabilize. Therefore, there are always more solid images and picture images represented by photographs than figures and letters as originals, which is very effective for users who want to reproduce beautifully reproduced photographs and the like.

From the developing units 10 and 10 ′, the surplus collected developer is sent to the collected developer storage unit 500 by a developer transfer unit such as the collection tube 121. The collected developer storing means 500 may be provided to be attached to the toner and developer storing / mixing means 400, or may be provided separately therefrom. At this time,
When the installation distance between the developing means 10, 10 'and the collected developer accommodating means 500 is long, or when the collected developer accommodating means is provided at the same level or at an upper position of the developing means, the discharging type powder pump is used. Providing at the end of the collecting screw 120 of 10, 10 'or providing a suction type powder pump in or between the collecting developer accommodating means 500 makes it possible to more reliably transfer the collecting developer. Becomes possible. FIG.
Shows an example in which a discharge type powder pump is provided on the developing means 10 and 10 'side.

In FIG. 10, the collecting screw 120 ′
At the end of the rotor 451 'of the powder pump unit 450'
As described above, air is sent to the powder pump unit 450 'to ensure the transfer of the recovered developer.

In the powder pump, a stator made of a rubber material slides on a rotor made of a metal material. The durability of the powder pump is determined by the inability to maintain the dimensions (specifically, the amount of bite) between the stator and the rotor. Usually, the rubber material wears out and its life is extended.

In order to improve the durability of the powder pump,
It is effective to suppress the wear of the stator. For this purpose, a rubber material is selected, and in this example, EPDM is used.
Further, it is desired to reduce the exercise time of the powder pump.

The powder pump used for transferring the collected developer is usually stopped because the transfer amount of the collected developer per unit time is extremely small, and when the amount of the collected screw is accumulated in the collection screw 120 ′, The intermittent operation of the powder pump, which is a method of operating, has a great effect on improving the durability of the powder pump. As a method of the intermittent operation of the powder pump, it is possible to use a conventionally well-known technique such as a drive by a dedicated motor independent of a drive of the developing sleeve and the stirring member, and a method of performing ON / OFF control through an electromagnetic clutch. is there. In addition, the control signal at this time can be said to be easily possible by the conventional technique, for example, by controlling the dedicated motor and the electromagnetic clutch through the timer circuit from the developing sleeve drive signal.

The toner / developer storing / mixing means 400
Since it can be unitized separately from the developing means 10 and only needs to be connected to the supply pipe 111 and the recovery pipe 121,
There are few restrictions on the installation location, and it is excellent in securing an economical developer storage amount and in the operation quality of developer exchange, productivity in assembling, adjustment, and the like. Further, since the degree of freedom in the arrangement of the respective device units of the image forming apparatus is increased, the replenishing toner storage member 600 can be disposed at a position where the user can easily perform the toner replenishing operation. Benefits can be obtained.

The operability of toner supply can be further improved by using a detachable toner cartridge system conventionally used for the toner container 600 for replenishment. In this case, since the shape of the toner cartridge does not depend on the developing means 10, the operability of toner replenishment can be improved, and the capacity can be freely secured. As a result, the productivity is further improved and the economic effect is greatly improved. This makes it possible to reduce the cost, and the increase in toner capacity improves the maintainability of the user.

According to the present developing means, not only is the structure of the developing means very simple, but also the driving of the developing device is only required to drive the developing sleeve and the screw for supplying / collecting the developer. As a result, miniaturization, simplification, low cost, high reliability, power saving, and easy maintenance can be achieved. Needless to say, the above-described effects can be obtained as a whole of the image forming apparatus.

It is also very effective in terms of operability and maintainability to make the carrier accommodating section 412 into a cartridge and make it detachable. The developer storage / mixing device only needs to connect the developer supply pipe / developer recovery pipe and the drive / control wire bundle to the machine main body, and should be a separate unit independent of the machine main body. It is obvious that is possible. In this case, the restriction on the size of the machine main body is reduced, and a large amount of replenishing toner, developer, and collected developer can be stored. It is possible.

Since the present invention uses a powder pump, a flexible hose can be used for the supply pipe and the recovery pipe.

[0065]

According to the present invention, according to the above construction, the size of the developing device and the main assembly of the device can be maintained at a proper level, the developer replacement interval can be lengthened, and the developer replacement operation can be simplified. It has the possible advantages.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of an image forming apparatus and a configuration of a developing device according to the present invention.

FIG. 2 is a schematic perspective view including a developing unit of the present invention.

FIG. 3 is a cross-sectional view showing one end side of a developing unit of the present invention.

FIG. 4 is a schematic sectional view showing another example of the developing means of the present invention.

FIG. 5 is a side center sectional view showing a toner and developer accommodating / mixing unit of the present invention.

FIG. 6 is a front center sectional view showing a toner and developer accommodating / mixing unit of the present invention.

FIG. 7 is a side view of one side of FIG. 5;

FIG. 8 is another side view of FIG. 5;

FIG. 9 is a front view of FIG. 5;

FIG. 10 is a schematic sectional view showing another embodiment of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 10 Developing means 100 Developing sleeve 111a ... Developer inlet 121a ... Developer outlet 150 ... Regulatory member 300 ... Developer storing unit 400 ... Toner and developer storing / mixing means 411 ... Toner storing part 412 ... Carrier storing part

Claims (9)

[Claims] 1. An image forming apparatus, comprising: a developer that is arranged around a latent image carrier and is formed by mixing a toner and a carrier to apply a developer to visualize an electrostatic latent image formed on the latent image carrier; In the image forming apparatus having a developing unit, a storage unit that is separately disposed at a location different from the developing unit and stores the toner and the carrier, and a mixing ratio of the toner and the carrier stored in the storing unit is prepared. An image forming apparatus comprising: a developer mixing unit; and a developer transfer unit that transfers the developer prepared by the developer preparation unit to the developing unit. 2. The image forming apparatus according to claim 1, wherein said developing means receives a developer prepared by said developer preparing means and a developer outlet which discharges a predetermined amount or more of developer. An image forming apparatus comprising: 3. The image forming apparatus according to claim 1, wherein said storage means and said developer mixing means are provided in one unit as a developer storage and mixing unit. . 4. The image forming apparatus according to claim 1, wherein the storage units each independently include a toner storage unit and a carrier storage unit, and a supply unit is provided in each of the toner storage unit and the carrier storage unit. An image forming apparatus, which is provided. 5. The image forming apparatus according to claim 1, wherein said developer mixing means is provided in said developer accommodating / mixing unit and partitions a supplied toner and a carrier. And a carrier supply hole formed in the partition member. 6. The image forming apparatus according to claim 1, further comprising: a developer transfer unit configured to transfer the prepared developer to the development unit below the developer preparation unit. An image forming apparatus comprising: 7. An image forming apparatus according to claim 1, wherein said developer transfer means includes a powder pump. 8. The image forming apparatus according to claim 2, further comprising: a collection developer transfer unit configured to transfer the remaining developer applied to the development from the development unit to a collection developer storage unit that stores the remaining excess developer. An image forming apparatus, wherein the collected developer transfer means includes a powder pump at the developer outlet. 9. The image forming apparatus according to claim 4, wherein the toner storage unit is formed in a container that can be detachably attached to the storage unit. Image forming apparatus.