JPH096133A - Developing device - Google Patents

Abstract

PURPOSE: To provide a developing device capable of obtaining a good developed image without having developing irregularity in the case of performing developing by making adequate amount of developer uniformly and easily carried in the shaft direction of the developer carrier in a condition obtained before the developing device is used. CONSTITUTION: The developer 3 previously set inside a developer housing part A is housed by an amount more than the amount capable of being carried on a developing sleeve 4 by the magnetic force of a magnetic pole 5a, and a hollow part 10 for housing excessive developer 3 is formed at a position where the developer unable to be carried on the sleeve 4 falls by gravity in the lower part of a developing device casing 2 is prevented from sticking to the sleeve 4 by the magnetic force of the magnetic pole 5a again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a facsimile machine, a printer, and the like, and more specifically, a toner containing portion for containing toner and a toner containing magnetic particles and toner. A developing device comprising a developer containing portion for containing a component developer, and a developing device disposed inside the developing device so as to face a latent image carrier of an image forming apparatus and having a magnetic field generating means therein. A rotatable developer carrying body carrying a developer, and forming a developer layer along the peripheral surface of the developer carrying body in the developer containing section, and applying the toner in the toner containing section to the developer. The present invention relates to a developing device adapted to be incorporated in a layer.

[0002]

2. Description of the Related Art Conventionally, a developing device of this type has a small amount of a two-component developer consisting of magnetic particles and toner contained in a developer accommodating portion. In this state, the developer is uniformly carried in the axial direction of the developer carrying member, and uneven development does not occur during development. However, when an image forming apparatus having such a developing device is transported to the user, a part of the developer that has been uniformly carried in the axial direction of the developer carrying body may drop due to shock or vibration. When such a drop occurs, since there is no mechanism for evenly distributing the developer in the axial direction, the developer carried on the developer carrying member is biased in the axial direction, resulting in uneven development during development. Sometimes appeared. Further, in a developing device in which a user or an operator stores the developer in the developer storage portion before use, the developer is not put on the developer carrier unless the developer is gently inserted. The developer that must be carried falls down to the bottom of the developing device as it is or is carried unevenly in the axial direction of the developer carrying body, so the developer is stored to prevent uneven development during development. The work to do was very difficult.

In addition, in a state before the developing device is used, the developer accommodating portion is filled with 1.3 times or more of the normal filling amount of the developer so as to eliminate the difference in toner density. Is disclosed (for example, Japanese Patent Laid-Open No. 3-14
No. 4471). According to this, it is possible to prevent the developer carried on the developer carrier from dropping or being deviated in the axial direction of the developer carrier due to the above-described transportation vibration or the like. It is possible to eliminate the density difference of the developed image due to the uneven development.

[0004]

However, according to the above configuration, the developer contained in the developer containing section before the developing device is used is originally required in the developer containing section even when it is normally used. A large amount of developer is still contained. In such a state, for example, when the toner is consumed by the development, the volume of the developer carried on the developer carrier decreases by the amount of the consumed toner, and before using the developing device, The developer dropped onto the lower part of the developing device without being carried on the developer carrying member by the magnetic force of the magnetic field generating means may be carried again on the developer carrying member by the magnetic force. As described above, when the developer dropped to the lower part of the developing device is carried again on the developer carrying member due to the consumption of toner by the development, the portion carried on the developer carrying member is developed. There is a problem in that the amount of toner consumed from the toner storage portion is not properly taken into the agent, resulting in white spots and uneven development. Further, even if the developer having a desired toner concentration is stored in the developer containing portion in advance, if the developer not magnetically carried on the developer carrying body is present in the developer containing portion, the Since the amount of the magnetic particles is larger than the originally required amount, there is a problem that at the time of development, the toner concentration may be different from the toner concentration when the developer is stored.

The present invention has been made in view of the above problems, and an object of the present invention is to supply an appropriate amount of the developer in the axial direction of the developer carrier in a state before using the developing device. (EN) Provided is a developing device capable of obtaining a good developed image free from uneven development during development by uniformly and easily supporting it.

[0006]

In order to achieve the above object, a developing device according to a first aspect of the invention is a developer containing a toner containing portion containing a toner, and a two-component developer containing magnetic particles and toner. A developing device formed of a container, and disposed inside the developing device so as to face the latent image carrier of the image forming apparatus, has magnetic field generating means therein, and is rotatable to carry the two-component developer. A developer carrier, a developer layer is formed in the developer container along the peripheral surface of the developer carrier, and the toner in the toner container is taken into the developer layer In the apparatus, the amount of developer stored in advance in the developing device is more than the amount that can be carried on the developer carrier by the magnetic force of the magnetic field generating means, and the developer cannot be carried on the developer carrier. In addition, the developer that has dropped under the developing A position that does not adhere to the developing time bearing member Te, is characterized in that the formation of the cavity for accommodating the developer.

In particular, the developing device of claim 2 is characterized in that, in the developing device of claim 1, a seal member for closing the opening of the cavity is provided.

In particular, the developing device of claim 3 is characterized in that, in the developing device of claim 1, a partition member for partitioning the toner containing portion and the developer containing portion is provided.

In particular, the developing device according to claim 4 is the developing device according to claim 1, wherein the toner agitating member provided in the toner accommodating portion is such that the outermost track of the toner agitating member is the developer carrying member. It is characterized in that it is arranged at a position where it does not overlap with the developer carried on the developer and the developer dropped from the developer carrying body.

According to a fifth aspect of the present invention, there is provided a developing device including a toner containing portion containing toner, a developer containing portion containing a two-component developer containing magnetic particles and toner, and a developing device inside the developing device. And a rotatable developer carrier, which is disposed so as to face the latent image carrier of the image forming apparatus, has magnetic field generating means therein, and carries the two-component developer, and stores the developer. In a developing device in which a developer layer is formed along the peripheral surface of the developer carrying member inside the developing unit and the toner in the toner storing unit is taken into the developing agent layer, the developing device is previously stored in the developing unit. The amount of the developer to be placed is equal to or more than the amount that can be carried on the developer carrying member by the magnetic force of the magnetic field generating means, and the toner concentration of the developer initially stored in the developing device is the toner concentration at the time of use. Set lower than, and carried on the developer carrier Without this, a hollow portion for accommodating the developer is formed at a position where the developer, which has fallen under its own weight to the lower part of the developing device, does not adhere to the carrier during the development due to the magnetic force. Is.

[0011]

In the developing device according to claim 1, the amount of the developer stored in the developer storing portion in advance is determined by the magnetic force of the magnetic field generating means stored inside the developer carrier. Since it is more than the amount that can be carried on the carrier,
When the developer carrier is rotated before using the developing device, the magnetic force of the magnetic field generating means prevents the developer not magnetically carried on the developer carrier from reaching the magnetic force of the magnetic field generating means. It will fall into the cavity formed at a certain position. Here, the magnetic force of the magnetic field generating means is usually set so as to have a substantially uniform strength in the axial direction of the developer carrying member. Therefore, even if no special mechanism for leveling the developer in the axial direction of the developer carrier is provided, excess developer that cannot be carried by magnetic force can be stored in the cavity only by the rotation of the developer carrier. When dropped, a developer having a substantially uniform layer thickness is carried in the axial direction of the developer carrying member. Further, the developer contained in the cavity without being magnetically supported on the developer carrier does not adhere to the developer carrier again during development. Therefore, the developer once dropped adheres to the developer carrying member again during the development, so that the toner consumed by the development cannot be sufficiently taken from the toner containing unit into the developer containing unit. Unlike the conventional device which may be feared, the toner consumed in the developer accommodating portion can be reliably taken in from the toner accommodating portion.

Particularly, in the developing device of claim 2, when the developer is first stored in the developer storage portion, the developer carried on the developer carrier by the magnetic force of the magnetic field generating means. May not carry the maximum amount of developer that can be carried by the magnetic force of the magnetic field generating means. Therefore,
In order to surely carry the magnetic force on the developer carrying member again, the developer which has not been carried by the magnetic force and is dropped from the developer carrying member, so that the development is performed while the opening of the cavity is closed by the seal member. The agent carrier is rotated. Then, while rotating the developer carrying member, the developer is carried on the developer carrying member as long as magnetic force can be carried, and is made uniform in the axial direction of the developer carrying member. Then, the magnetic force is not carried on the developer carrying member, and the excess developer which has been dropped on the seal member is accommodated in the cavity by removing the seal member. During the development, the magnetic force is not carried again on the developer carrying member.

Particularly, in the developing device according to the third aspect, before the developing device is used, the toner containing portion and the developer containing portion are partitioned by a partition member so that magnetic force is carried on the developer carrying body. The toner in the toner containing portion is prevented from entering the cavity before the undeveloped developer is dropped into the cavity. Further, when the developer carrying member is rotated to magnetically carry the developer on the developer carrying member, the size of the space in the developer containing portion where the developer does not exist may change. With the change, the toner may be taken into the developer containing section from the toner containing section. If the toner is taken into the developer before the developing device is used, there is a possibility that the toner may be set to an initial density different from the toner density of the developer initially stored in the developer storage portion. . However, the partition member prevents the fluctuation of the initial toner concentration due to the toner taken into the developer from the toner containing portion before the developing device is used, so that the toner of the developer initially contained in the developer containing portion is prevented. Maintain the density at the initial toner density. Then, when the setting of the developer is completed, the partition member is removed, the toner containing portion and the developer containing portion are communicated with each other, and the toner is taken into the developer containing portion, and then the developing operation is started.

Particularly, in the developing device of claim 4, the outermost peripheral track of the toner agitating member provided in the toner accommodating portion is an extra developer dropped from the developer carrying member, and the developer. By disposing the toner stirring member at a position where it does not overlap with the developer carried on the carrier, the developer dropped from the developer carrier when the toner stirring member is rotated. , Is never returned to the range of the magnetic force generated by the magnetic field generating means again, and
The toner stirring member does not scrape off the developer already carried on the developer carrying member.

Further, in the developing device of claim 5, before the developing device is used, the toner concentration in the developer accommodated in the developer accommodating portion is compared with the toner concentration in the normal developing operation. By setting it low, it becomes easy to carry the developer containing a large amount of magnetic particle components on the developer carrier by the magnetic force of the magnetic field generating means. Therefore, even if the opening of the cavity provided at a position where the magnetic force of the magnetic field generation means does not reach is not covered with a seal member or the like, the developer accommodated in the developer accommodating portion is It does not fall onto the hollow portion as it is without being loaded with magnetic force. (Hereinafter, margin)

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a developing device of an electrophotographic copying machine (hereinafter referred to as a copying machine) which is an image forming apparatus will be described below. FIG. 1 is a schematic configuration diagram of the developing device according to the present embodiment. This developing device is disposed laterally of a cylindrical photosensitive drum 1 which is a latent image carrier used in a copying machine, and a developing device casing 2 having an opening formed toward the photosensitive drum 1 is provided. A developing sleeve 4 made of a non-magnetic material as a developer carrying member for carrying the developer 3 made of toner and magnetic particles on the surface, which is partially exposed from the opening, and fixedly arranged inside the developing sleeve 4. A magnetic roller 5 as a magnetic field generating means, a doctor 6 as a developer regulating member for regulating the amount of the developer carried on the developing sleeve 4 and conveyed, a developer accommodating case 7, and a toner accommodating portion. A toner hopper 8 and the like are provided.

The developer accommodating case 7 accommodates the developer which has not been supplied to the developing position between the developing sleeve 4 and the photoconductor drum 1 and which is prevented from advancing by the doctor 6. The accommodation part A is formed. In the magnet roller 5 fixedly arranged inside the developing sleeve 4, the developer 3 in the developer accommodating section A is carried on the developing sleeve 4 at a position facing the developer accommodating section A. The magnetic pole 5a is arranged. Further, the toner hopper 8 is
A toner replenishing port 8a facing the surface of the developing sleeve 4 is provided adjacent to the upstream side of the developer accommodating portion A in the developer conveying direction, and a space adjacent to the toner replenishing port 8a is
A toner agitator 9 is provided as a toner stirring member for feeding the toner in the toner hopper 8 indicated by the reference numeral 3a toward the toner supply port 8a while stirring. The position of the rotating shaft and the length of the wing of the toner agitator 9 are adjusted, and the outermost track of the agitator is set so as not to come into contact with the developer 3, as indicated by the broken line in the figure. Further, the magnetic pole 5a is provided below the developing device casing 2.
A cavity 10 for accommodating the developer that has fallen without being carried on the developing sleeve 4 at a position where the magnetic force of the
Are formed.

In the developing device having the above-mentioned structure, the developer 3 carried on the developing sleeve 4 is conveyed to the doctor 6 side on the sleeve as the developing sleeve 4 rotating in the direction of the arrow a in FIG. It is regulated by 6 and thinned. The thinned developer 3 is conveyed to a developing area facing the photoconductor drum 1 rotating in the direction of arrow b in the figure. Then, in the developing area, the toner is supplied to the electrostatic latent image formed on the photosensitive drum 1 in contact or non-contact, and the electrostatic latent image is visualized. The developer 3 that has not been used for visualization is conveyed to the toner supply port 8a side on the sleeve as the developing sleeve 4 rotates.
After the new toner 3a sent out by the toner agitator 8 in the toner hopper 8 and supplied from the toner supply port 8a is taken in, it returns to the developer accommodating section A. Then, the internal pressure of the developer 3 containing the new toner 3a at the regulating portion by the doctor 6 increases, and the toner of the developer 3 is frictionally charged. In this way, by the internal pressure of the developer in the developer accommodating portion A,
Since the toner in the developer 3 on the developing sleeve 4 can be charged, a complicated stirring / conveying mechanism using a paddle, a screw or the like for charging or stirring the developer is unnecessary.

On the other hand, a part of the developer 3 which is not supplied to the developing area and whose progress is blocked by the doctor 6 is replenished with toner in the toner hopper 8 by the internal pressure and gravity of the developer 3 itself in the developer container A. Move toward mouth 8a. The developer 3 that has moved to the vicinity of the toner supply port 8a is attracted to the developing sleeve 4 side by the magnetic force of the magnetic pole 5a, and is conveyed to the doctor 6 side as the developing sleeve 4 rotates. Circulate inside.

Further, in the developing device having the above structure, when the amount of toner replenished to the developer 3 increases and the toner concentration increases, the bulk of the developer 3 increases accordingly, so that the developer 3 is replenished with toner. The toner drops to the opening 8a and covers the opening of the toner supply opening 8a. Therefore, the amount of toner taken into the developer 3 on the developing sleeve 4 is reduced.
Due to this decrease in the amount of toner taken in, the toner concentration of the developer 3 is always kept below a certain concentration. On the contrary, when the toner concentration of the developer 3 becomes low, the bulk of the developer 3 decreases, and the developer 3 does not block the toner supply port 8a.
A predetermined amount of toner is taken into the developer 3 on the developing sleeve 4, and the toner concentration of the developer 3 is always maintained at a certain level or higher. As described above, since the toner concentration can be controlled within a substantially constant range, a complicated toner concentration control mechanism using a toner concentration sensor, a toner replenishing member, etc. is unnecessary.

Next, a procedure to be carried out before using the developing device of this embodiment for the first time will be described. Shipped from the factory,
In the developing device when it reaches the user's hand, as shown in FIG. 1, the opening of the cavity 10 is closed by a shutter 11 as a seal member. Also, the toner supply port 8
A is also partitioned by a partition shutter 12 as a partition member. Then, in the developer accommodating portion A at this time,
During development, the initial developer, which is set to have the same toner density as the optimum toner density that is controlled so as to obtain a good developed image, is contained in an amount larger than that which can be carried by the magnetic force of the magnetic pole 5a of the magnet roller 5. Has been done.

First, the developing sleeve 4 is rotated in the direction of the arrow in the figure until the initial developer is sufficiently carried on the peripheral surface of the developing sleeve 4 by the magnetic force of the magnet roller 5. Then, at the time of this rotation, the developer that could not be carried by the magnetic force of the magnetic pole 5a of the magnet roller 5 falls to the lower portion of the developing device casing 2.

Next, the shutter 11 is pulled out to the front side of the drawing, and the excess developer which is not carried on the developing sleeve 4 by the magnetic force of the magnetic pole 5a is dropped into the hollow portion 10 under the developing device casing 2 to be accommodated therein. By preventing the toner from adhering to the developing sleeve 4 again during the development, the fluctuation of the amount of the developer carried on the developing sleeve 4 during the development is prevented. Furthermore,
The partition shutter 12 partitioning the toner supply port 8a is pulled out to the front side of the drawing, the toner hopper 8 and the developer accommodating portion A are communicated with each other, and the toner in the toner hopper 8 is brought into the developer accommodating portion A.

Since the shutter 11 as the seal member and the partition shutter 12 as the partition member used in this embodiment are not installed again in the apparatus once they are pulled out, for example, each of them is a film-like seal. You may comprise.

According to this embodiment, normally, the magnetic force of the magnetic pole 5a is set so as to have a substantially uniform strength in the axial direction of the developing sleeve 4, so that the initial developer is applied in the axial direction of the developing sleeve 4. Even if a special mechanism for leveling is not provided, the developing sleeve 4 can be rotated by a simple method of dropping the developer that could not carry the magnetic force on the developing sleeve 4 to the lower portion of the developing device casing 2. The thickness of the developer layer formed along the peripheral surface can be made substantially uniform in the axial direction. Therefore, it is possible to prevent development unevenness due to uneven setting of the developer in which the initial developer is biased in the axial direction of the developing sleeve 4. Further, since the cavity 10 is closed by the shutter 11 until the initial developer is uniformly set in the axial direction of the developing sleeve 4, before the sufficient amount of the developer is carried on the developing sleeve 4. Therefore, it is possible to prevent the initial developer from dropping into the cavity 10. If only the shutter 11 is provided and the shutter 12 is not provided, the toner in the toner hopper 8 may enter into the hollow portion 10 before dropping the excess developer into the hollow portion 10. It also has the effect of preventing it.

Further, in the above-described conventional developing device which stores a larger amount of the initial developer than in the normal use, the excessive developer dropped from the developing sleeve 4 cannot be carried by the magnetic force of the magnetic pole 5a and is being developed. When the toner adheres to the developing sleeve 4 again, the amount of the developer in the developer accommodating portion A fluctuates irrespective of the toner consumption, and there is a possibility that the toner concentration cannot be controlled properly. However, in this embodiment, the excess developer not used for the development is filled with the cavity portion 10.
The above-mentioned problem does not occur because it is made to fall to and does not contribute to the development again. Further, since the toner replenishing port 8a is closed by the partition shutter 12 until the initial developer is uniformly set in the axial direction of the developing sleeve 4, when the initial developer is set, the toner hopper 8 inside the developer accommodating portion A is set. The amount of developer does not fluctuate due to the toner being taken into. Therefore, it is possible to prevent the fluctuation of the toner density due to the fluctuation of the toner amount.

Further, as another embodiment, when the shutter 11 of FIG. 1 is not provided, the toner concentration of the initial developer stored in the developer storage portion A in advance is made lower than the toner concentration at the time of development. It is preferable to set and store the magnet roller 5 in an amount larger than that which can be carried by the magnetic force of the magnetic pole 5a. If the toner density at the time of development is too low, the followability at the time of solid development becomes poor, and magnetic particles may adhere to the photosensitive drum 1. If it is too high, uneven development may occur. Therefore, in the apparatus of this embodiment, the toner concentration during development is controlled to be about 15 to 25 wt%. Also,
Regarding the toner concentration of the initial developer, by increasing the magnetic particle component, the magnetic force from the magnetic pole 5a can be surely carried on the developing sleeve 4, and the magnetic particles can be carried by the photosensitive drum 1.
In order to satisfy the two requirements of not being adhered to the upper side, compared with the weight% of the toner concentration at the time of development,
The initial developer set to 1/4 to 1/2 is contained in the developer container A.

According to this, since the initial developer contained in the developer accommodating portion A in advance in an amount larger than the amount of the developer that can be carried by the magnetic force of the magnetic pole 5a contains a large amount of magnetic particle components, the magnetic force of the magnetic pole 5a causes It is attracted onto the developing sleeve 4 and reliably carried. Therefore, when the developing sleeve 4 is rotated in the direction of the arrow, the amount of the developer that is not carried on the developing sleeve 4 and drops into the hollow portion 10 as it is can be reduced. Further, since the toner concentration in the developer at this time is almost the same as that when the toner is consumed by the development, the partition shutter 12
When the toner hopper 8 and the developer accommodating portion A are communicated with each other so that the toner in the toner hopper 8 can be taken into the developer accommodating portion A. Since it is taken into the developer in the section A, it can be controlled so that the toner concentration will be optimum thereafter.

Further, the toner agitator 9 of this embodiment is
The mounting position of the toner agitator 9 and the length of the wing are adjusted so that the outermost track during rotation does not overlap with the developer dropped in the cavity 10 and the developer 3 already carried on the developing sleeve 4. However, unlike the case where the outermost track when the toner agitator 9 rotates overlaps the developer 3, the toner agitator 9 removes the excess developer dropped from the developing sleeve 4 again. It will not be returned to the accommodation section A. Therefore, it is possible to prevent the variation of the developer amount in the developer accommodating portion A and also prevent the developer 3 from mixing into the toner hopper 8. Further, it is possible to prevent the toner agitator 9 from scraping off the developer 3 already carried on the developing sleeve 4, so that the layer thickness of the developer 3 carried on the developing sleeve 4 becomes uneven. It is possible to obtain a good developed image with no development unevenness.

[0030]

According to the developing device of the present invention, the developer carrying member can be carried only by the rotation of the developer carrying member without specially providing a mechanism for leveling the developer in the axial direction of the developer carrying member. The thickness of the developer layer formed along the peripheral surface of the body can be easily and substantially made uniform. Therefore, when a developing operation is performed, there is an excellent effect that a good developed image without development unevenness can be obtained. Further, the amount of the developer contained in the developer accommodating portion in an amount larger than that which can be carried on the developer carrier by the magnetic force of the magnetic field generating means is increased by the magnetic force of the magnetic field generating means as the developer carrying body rotates. Since the amount of developer that could not be carried on the agent carrier is dropped into the cavity provided in the position where the magnetic force of the magnetic field generating means does not reach,
It is not necessary to accurately store the amount of the developer in the developer storage portion. In addition, since the developer once dropped from the developer carrier into the cavity does not adhere to the developer carrier again, the developer once dropped onto the developer carrier again during development. Unlike the conventional device in which the toner consumed by the development may not be sufficiently taken into the developer containing portion from the toner containing portion by adhering to the inside of the developer containing portion from the toner containing portion to the developer containing portion. The consumed toner can be reliably taken in.

In particular, according to the developing device of the second aspect, by rotating the developer carrier while the opening of the cavity is closed by the seal member, the developer once dropped to the lower part of the developing device is removed. Magnetic force can be surely carried on the developer carrying member.

Particularly, according to the developing device of the third aspect, before the developing device is used, the operation of rotating the developer carrying member to magnetically carry the developer on the developer carrying member is performed by the partition member. Since the toner storage portion and the developer storage portion are separated from each other, the toner in the toner storage portion is removed before the developer not carried on the developer carrier is dropped into the cavity. It is possible to prevent the unnecessary developer from falling into the hollow portion by preventing the developer from entering the hollow portion. Further, the toner concentration due to the toner being taken into the developer accommodating portion from the toner accommodating portion due to the change in the space inside the developer accommodating portion during the rotation of the developer bearing member before the developing device is used. Therefore, the toner concentration of the developer when first stored in the developer storing section can be maintained at the initial concentration state.

In particular, according to the developing device of the fourth aspect, before the developing device is used, the developer which has not been magnetically carried on the developer carrying member is dropped by the toner stirring member again during the development. Since the magnetic field generated by the magnetic field generating means does not return the magnetic field to the range, it is possible to prevent the amount of developer magnetically carried on the developer carrying member from fluctuating regardless of the toner consumption amount due to development. Further, since the toner agitating member does not scrape off the developer already carried on the developer carrier, the developer is mixed in the toner accommodating portion or carried on the developer carrier. It is possible to prevent unevenness in the layer thickness of the developed developer.

According to the developing device of the fifth aspect, the developer containing a large amount of magnetic particle components before the developing device is used is carried on the developer carrier by the magnetic force of the magnetic field generating means. The developer housed in the housing portion does not carry magnetic force on the developer carrier, and does not fall as it is into the cavity provided in a position where the magnetic force of the magnetic field generating means does not reach, It is possible to surely carry the developer on the developer carrier without providing a seal member for closing the opening of the cavity.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a developing device according to an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Developer casing 3 Developer 3a Toner 4 Development sleeve 5 Magnet roller 5a Magnetic pole 6 Doctor 7 Developer storage case 8 Toner hopper 8a Toner supply port 9 Toner agitator 10 Cavity 11 Shutter 12 Partition shutter A Developer storage

Claims (5)

[Claims] 1. A developing device including a toner containing portion containing toner, a developer containing portion containing a two-component developer composed of magnetic particles and toner, and a latent image of an image forming apparatus in the developing device. A rotatable developer carrier that has a magnetic field generating means therein and that carries the two-component developer, the developer carrier being disposed inside the developer container. In a developing device in which a developer layer is formed along the peripheral surface and the toner in the toner containing portion is taken into the developer layer, the amount of the developer stored in the developing device in advance is The developer, which has more than the amount that can be carried on the developer carrying member by the magnetic force of the generating means and cannot be carried on the developer carrying member and falls to the lower part of the developing device by its own weight, is again developed by the magnetic force. When the developer is stored in a position where it does not adhere to the carrier Developing apparatus is characterized in that the formation of the cavity. 2. The developing device according to claim 1, further comprising a seal member for closing the opening of the cavity. 3. The developing device according to claim 1, further comprising a partition member for partitioning the toner containing portion and the developer containing portion. 4. A toner agitating member provided in the toner accommodating portion, wherein the outermost peripheral track of the toner agitating member falls from the developer carried on the developer carrying member and from the developer carrying member. The developing device according to claim 1, wherein the developing device is arranged at a position where it does not overlap the developer. 5. A toner accommodating portion for accommodating toner, a developing device including a developer accommodating portion for accommodating a two-component developer composed of magnetic particles and toner, and a latent image of an image forming apparatus in the developing device. A rotatable developer carrier that has a magnetic field generating means therein and that carries the two-component developer, the developer carrier being disposed inside the developer container. In a developing device in which a developer layer is formed along the peripheral surface and the toner in the toner containing portion is taken into the developer layer, the amount of the developer stored in the developing device in advance is The toner concentration of the developer having an amount that can be carried on the developer carrying member by the magnetic force of the generating means and initially stored in the developing device is set to be lower than the toner concentration at the time of use, It cannot be fully loaded on the agent carrier, and its own weight is applied to the bottom of the developing unit. Developing device dropped developer, characterized in that re-positioned so as not to adhere to the developing time bearing member by magnetic force to form a cavity for accommodating the developer.