JP2001175081A - Developer replenishing/recovering means, developing device and image forming device provided with the developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a maintenance performance by automatically and gradually replacing developer in a developer container, and also, to provide a developing device and an image forming device capable of improving the maintenance performance at a low cost by introducing an easy and simple constitution, as for a monochromatic image forming device, a tandem type or variously constituted full color image forming device. SOLUTION: A replenishing developer storing part 5a and a recovered developer storing part 5b are integrally formed, and also, arranged nearly above the developing container 2, and the device is provided with a magnet 7 for recovering and holding the developer from the developing container 2 and carrying the developer on the surface by generating a magnetic field, and which is freely rotated around an axial line, and a scraper 8 which comes close to, or comes in press contact with the surface of the magnet 7 so as to peel the developer off the surface of the magnet 7 and recover the developer into the recovered developer storing part 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A conventional electrophotographic image forming apparatus employs a developer containing a non-magnetic toner and a magnetic carrier in an image forming apparatus for forming a chromatic image. Component development systems are widely used.

The two-component developing system has advantages such as stability of image quality and durability of the apparatus as compared with other developing systems currently proposed. On the other hand, since the deterioration of the developer due to long-term durability, particularly the deterioration of the carrier, has been inevitable, it is necessary to perform an operation of replacing the developer with the long-term use of the image forming apparatus.

Several solutions to this problem have been proposed.

[0005] For example, according to Japanese Patent Publication No. 2-15991,
In a developing apparatus for an electrophotographic copying machine, comprising: a stirring unit for stirring the carrier and the toner; and a developing roll serving as a developer carrier for supplying the developer stirred by the stirring unit to the photosensitive member serving as a latent image carrier. A replenishment developer accommodating unit formed by separating or integrating the carrier replenishing device and the toner replenishing device is provided above the stirring unit, and a developer overflow portion serving as a collected developer accommodating unit is provided on a side wall of the developing device housing as a developer container. With this arrangement, new developer can be replenished little by little by the replenishing device and can be discharged from the developer overflowing portion, so that the characteristics of the developer in the developing device housing can be kept constant. As a result, The image quality of the copy can be kept constant. Further, the old developer in the developing device housing is automatically discharged sequentially from the developer overflow portion. Therefore, the developing device is removed from the copying machine, the old developer in the developing device housing is taken out, and new developer is removed. After the developer is refilled, a troublesome replacement operation of the developer, such as mounting the developing device again, is not required, and the scattering of the developer is prevented, which is sanitary.

That is, by gradually replacing the deteriorated developer (carrier) with a new one, the apparent progress of deterioration of the carrier is stopped, and the characteristics of the entire developer are stabilized. As a result, the work of replacing the developer is not required, and the maintainability is improved.

A configuration in which this method is combined with the configuration of a rotary developing device is proposed in Japanese Patent Laid-Open No. 9-218575. According to this configuration, the rotary developing device is provided with a developer replenishing means. And supply the necessary developer to the developing unit. Excess developer in the developing device is discharged by utilizing a change in the direction of action of gravity due to the rotation of the rotating body. In this way, by using the movement unique to the rotating body,
Excess developer can be discharged with a simple structure.

In addition, various systems which do not use a rotary developing device have been proposed. For example, a developing device as shown in FIG. 8 has been proposed in JP-A-10-63074.

[0009]

On the other hand, in recent years, as the market for full-color copying machines and printers has expanded and various functions have been required, for example, a plurality of photosensitive drums are arranged to provide high productivity. Many tandem-type image forming apparatuses that perform multiple transfer have been commercialized, and are expected to become one of the mainstream markets in the future.

However, in the image forming apparatus of the tandem type, the developing devices of the respective colors are fixedly arranged on the respective photosensitive drums, and a simple structure as proposed in Japanese Patent Application Laid-Open No. 9-218575 can be used. Did not. For this reason,
In order to adopt a method of gradually changing the developer in a tandem type image forming apparatus, see Japanese Patent Application Laid-Open No. 10-63.
A complicated configuration as shown in FIG. This is the same in an image forming apparatus that forms a monochromatic image.

That is, in the prior art, a single-color image forming apparatus, a tandem method for producing high productivity, and a full-color image forming apparatus of various configurations which do not employ a rotary developing device to take advantage of various features are not used. ,
Attempts to improve maintainability by gradually changing the developer gradually, on the contrary, complicate the configuration, leading to an increase in the cost of the main body.

Accordingly, the present invention provides a monochrome image forming apparatus,
In full-color image forming devices of various configurations including the tandem type, maintenance is improved by automatically changing the developer in the developer container gradually, and low cost maintenance is realized by adopting a simple configuration. It is an object of the present invention to provide a developing device and an image forming apparatus capable of improving the image quality.

[0013]

SUMMARY OF THE INVENTION The present invention mainly relates to a replenishment developer accommodating means capable of replenishing a new developer in a developer container accommodating a two-component developer containing a toner and a magnetic carrier. And a recovery developer storage means capable of recovering the deteriorated developer in the developer container. Developer supply and collection means capable of replacing the developer with new developer, wherein the supply developer storage means includes a supply developer storage container for storing a developer to be supplied into the developer container; A developer replenishing unit that can replenish the developer in the developer container into the developer container; the collected developer storing unit includes a developer collecting unit that can collect the developer from the developer container; A collection container for collecting the developer, In the developer supply and recovery means provided, the supply developer storage container and the recovered developer storage container are integrally formed and disposed substantially above the developer container, and the developer recovery means generates a magnetic field to generate the developer. A magnetic field generator that collects and holds the developer from the developer container, holds the developer on the surface, and is rotatable around the axis; and a magnetic field generator that separates the developer from the surface of the magnetic field generator and collects the developer in the collection developer container. A developer replenishing and recovering means, comprising: a peeling member which comes close to, abuts or presses against the surface.

Another main aspect of the invention of the present application is a developing device that visualizes the latent image as a developer image by applying a developer to a latent image carrier that carries the latent image,
A developing device comprising: a developer container containing a two-component developer containing a toner and a magnetic carrier; and the developer replenishing and collecting means.

Further, the invention according to another main application of the present invention is:
An image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, comprising: a latent image carrier for carrying a latent image; the developing device; and a developer image on the latent image carrier. An image forming apparatus comprising: a transfer unit that transfers the image to a medium.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described.

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, first, the surface of a photosensitive drum 28 serving as a latent image carrier charged by a charger 21 is exposed by a laser 22 so that the surface of the photosensitive drum 28 is exposed. An electrostatic latent image is formed on the photosensitive drum 28 by developing the latent image with the developing device 1 as a developing device. After the toner image is transferred to the recording paper 27 conveyed by the transfer belt 24 by the transfer bias by the transfer charger 23, the recording paper 27 is separated from the transfer belt 24, and is pressed and heated by the fixing device 25, Obtain a permanent image. On the other hand, the photosensitive drum 28 after the transfer is the photosensitive drum 2
After the remaining toner remaining on the photosensitive drum 8 is removed from the photosensitive drum 28 by the cleaner 26, it is provided for the next image formation.

Here, the developing device 1 will be described in detail.

The developing device 1 has a developing container 2 as a developer container.

The developing container 2 of the developing device 1 contains a two-component developer containing a non-magnetic toner and a magnetic carrier, and the mixing ratio thereof is about 1: 9 by weight. Note that this ratio should be appropriately adjusted in accordance with the charge amount of the toner, the carrier particle size, the configuration of the image forming apparatus, and the like, and does not necessarily have to follow this numerical value.

The developing container 2 has an opening (not shown) formed at a position facing the photosensitive drum 28, and the developing sleeve 3 is partially exposed outside the developing container 2 at the opening. It is arranged so that it can rotate.

The developing sleeve 3 rotates in the direction of the arrow in FIG. 1 during the developing operation, and carries the two-component developer from the inside of the developing container 2 in a layered manner on the surface thereof, and carries and carries it to the developing area facing the photosensitive drum 28. Then, a two-component developer is supplied to the developing area to develop the electrostatic latent image on the photosensitive drum 28. After the electrostatic latent image is developed, the developer on the developing sleeve 3 is transported along with the rotation of the developing sleeve 3 and collected in the developing container 2.

A developer cartridge 5 capable of storing a new developer to be supplied to the developer container 2 and a developer collected from the developer container 2 is disposed substantially above the developing device 1. And can be easily detached from the image forming apparatus main body.

The mixing ratio of the toner and the carrier of the replenishment developer contained in the developer cartridge 5 is not particularly limited to this value, but is about 9: 1 by weight. That is, the amount of toner is overwhelmingly larger than the ratio of the two-component developer in the developing container 2, and considering the volume ratio, it can be considered that a small amount of carrier is mixed in the toner. That is, when supplementing the toner consumed by image formation, a small amount of carrier is gradually supplied. If the ratio of the carrier of the developer to be replenished increases, the replacement amount of the carrier increases with the same amount of toner replenishment,
Although the two-component developer in the developing container 2 approaches a fresh state, the consumption of the carrier increases accordingly. For this reason,
It is preferable to determine an appropriate mixing ratio separately for each device.

The amount of the developer to be replenished is generally determined by a toner density detecting means or a toner image density detecting means, and any of these methods may be appropriately adopted by those skilled in the art. .

Next, a method of recovering the developer, which is a feature of the present invention, will be described with reference to FIGS.

In the image forming apparatus according to the present embodiment, a replenishment developer accommodating section 5a as a replenishment developer accommodating container and a collected developer accommodating section 5b as a collected developer accommodating container constituting a developer replenishing and collecting means are integrally formed. And a developer supply screw 4 serving as a developer supply means.
Magnet 7 as a magnetic field generator and scraper 8 as a peeling member
And

FIG. 2 is a diagram showing the developer supply screw 4, the developer cartridge 5, and the magnet 7 in the developing device 1 according to the present embodiment, as viewed from the left side in FIG.

As shown in FIG. 2, the developer cartridge 5 has a substantially cylindrical replenishment developer storage section 5a and a recovered developer storage section 5b integrally formed.

The replenishment developer accommodating portion 5a and the developer replenishment screw 4 constitute replenishment developer accommodation means. The replenishment developer accommodated in the replenishment developer accommodation portion 5a is rotated by the rotation of the developer replenishment screw 4. It is transported into the developing container 2. The rotation of the developer supply screw 4 is controlled by a developer supply amount control device (not shown), and an appropriate amount of the developer is conveyed and supplied into the developing container 2.

FIG. 3 is a view of the left side of FIG. 2 as viewed from the front in FIG.

The magnet 7 and the scraper 8 constitute a developer collecting means, and the developer collecting means and the collected developer accommodating portion 5b constitute a collected developer accommodating means.

As shown in FIG. 3, the magnet 7 has a substantially circular shape. In FIG.
It is magnetized at the poles, and is rotated in the direction of the arrow in FIG. 3 (counterclockwise) by a driving unit (not shown) different from the driving unit of the developer supply screw 4.

The shape of the magnet 7, the magnetized pattern, and the like are not limited to those described in the present embodiment, and may be, for example, a rod or a polygon. When the magnet 7 is not circular, a circle drawn by rotating a non-circular magnet may be used instead of the circular magnet 7 shown in the present embodiment and the like. Also, the magnetization pattern may be configured such that N and S poles are alternately arranged on the circumference.

The magnet 7 is close to the inner surface of the developing container 2 and close to the surface of the two-component developer contained in the developing container 2, and adheres an appropriate amount of the developer by magnetic force. The developer attached to the magnet 7 is conveyed to the vicinity of the collection port 6b of the collection developer container 5b as the magnet 7 rotates. Collection port 6
As shown in FIG. 3, b is provided with an appropriate clearance with respect to the magnet 7. A scraper 8 made of urethane rubber is installed near the left of the recovery port 6b in FIG. 2 to the right.
The developer transported by the rotation of the magnet 7 collects the developer 6
b passes through the right portion in FIG. 3, is scraped off by the scraper 8 on the left side, and is gradually
b.

In this embodiment, the scraper 8 is made of a separate member to improve the scraping property of the collected developer. However, in the present invention, the performance of the scraping member with respect to the magnet 7 may be maintained to some extent. If the scraping member is formed using a part of the recovery port 6b, a simpler configuration can be obtained.

The amount of the collected developer basically depends on the amount of rotation of the magnet 7, but also on the amount of the developer in the developing container 2. For example, if the amount of the developer in the developing container 2 increases or decreases,
Accordingly, the amount of the developer attached to the magnet 7 also increases or decreases. That is, the amount of developer collected by the magnet 7 acts in a direction to suppress a change in the amount of developer in the developing container 2. Since such characteristics can be used, if the magnetic force of the magnet 7, the position where the magnet 7 is arranged, and the like are set to appropriate values, there is no need to finely control the number of revolutions of the magnet 7, and The amount of the developer can be kept within an enclosure where the function as the developing device is normally performed.

When removing the developer cartridge 5, first, the developer cartridge 5 is rotated leftward in FIG. As a result, the collection port 6b is sealed by the shutter member 9, so that the contents of the collection developer container 5b do not leak. At this time, although not described in detail, the supply port 6 a where the developer cartridge 5 transfers the supply developer from the supply developer storage section 5 a to the developer supply screw 4 is also sealed by the shutter member 9. In this state, the developer cartridge 5 can be easily removed from the image forming apparatus main body by pulling it out toward the user in FIG. When the developer cartridge 5 is mounted, the reverse operation may be performed.

With the above configuration, the maintenance is improved by gradually and automatically changing the developer in the single-color image forming apparatus, and a simple configuration is adopted, thereby realizing and providing an image forming apparatus with low cost and high maintenance. And the object of the present invention is achieved.

(Second Embodiment) Next, a second embodiment of the present invention will be described. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 4 is a schematic sectional view showing a schematic configuration of an image forming apparatus according to a second embodiment of the present invention.

In the following description, the same symbols with the alphabets of Y, M, C and K are components for forming images of yellow, magenta, cyan and black, respectively. is there. For example, developing unit 1
If it is described as, it is four developing units 1Y, 1M,
It refers to matters common to 1C and 1K.

In such an image forming apparatus, the charger 2
The surface of the photosensitive belt 28B charged by
Exposure by 22 forms an electrostatic latent image on the photosensitive belt 28B. The latent image is first developed by driving the developing device 1Y to obtain a yellow toner image. On the other hand, the transfer paper 27 is transported from the paper feed cassette in the direction of arrow A by a paper feed device (not shown), and is attracted onto the transfer belt 24 by a suction means (not shown). The toner image forming timing and the supply timing of the transfer paper 27 are adjusted to appropriate values, and the toner image on the photosensitive belt 28B is transferred to the transfer paper 27 on the transfer belt 24 by the transfer bias by the transfer charger 23. . The residual toner remaining on the photosensitive belt 28B after the transfer is removed by the cleaner 26. Next, the photosensitive belt 28B is charged again,
The latent image formed by exposure by the LED 22 is
M is driven to develop and obtain a magenta toner image. The toner image is transferred onto the transfer paper 27 conveyed to the vicinity of the transfer charger 23 while the yellow toner image is transferred first and is attracted to the transfer drum 24D rotating in the direction of arrow B. Thereafter, similarly, the latent image on the photosensitive belt 28B is developed by the developing device 1C and the developing device 1K, and a yellow, magenta, cyan, and black toner image is formed on the transfer paper 27. The transfer paper 27 on which the toner images for four colors have been transferred is separated from the transfer drum 24D, and is conveyed in the direction of arrow C.
The image is pressed and heated by the fixing device 25 to obtain a permanent image.

Developing device 1 for each color, developer cartridge 5
Have almost the same configuration.

Next, a characteristic portion of the present embodiment will be described.

As shown in FIG. 4, in the present embodiment, the developing units 1Y, 1M, 1 for each color are provided below the photosensitive belt 28B.
C and 1K are arranged in parallel. Further, the developer cartridges 5Y, 5M, 5C, and 5K are housed in the apparatus by utilizing the space inside the photosensitive belt 28B, thereby making it possible to reduce the size of the entire apparatus. Further, the developer cartridges 5Y, 5M, 5C, 5K
Can be independently attached and detached from the front side of the image forming apparatus, and can be easily replaced when the replenishment developer becomes empty.

Next, the supply and recovery of the developer will be described in detail.

Developer cartridges 5Y, 5M, 5C, 5
K is disposed above the developing units 1Y, 1M, 1C, and 1K for the respective colors.

FIG. 5 is a view of the developing device 1 and the developer cartridge 5 of a certain color as viewed from the left side of FIG.

As shown in FIG. 4, the connection between the supply port 6a and the developer supply screw 4 and the connection between the magnet 7 and the recovery port 6b are further connected to the back side of the back end surface of the photosensitive belt 28B. That is, the replenishment developer and the recovered developer are
Both are delivered on the back side of the photosensitive belt 28B. still,
The delivery of the replenishment developer and the collected developer is not limited to the inner side, and it is sufficient that the delivery is performed at a position where the traveling of the photosensitive belt 28B is not hindered.

The method of collecting the developer is the same as in the first embodiment.

As described above, the object of the present invention can be achieved by the image forming apparatus of the present embodiment also in the image forming apparatus using the photosensitive belt and fixedly arranged in the developing device. Further, by incorporating a developer cartridge in the photosensitive belt as in this embodiment, the entire image forming apparatus can be downsized.

(Third Embodiment) Next, a third embodiment of the present invention will be described. The description of the same configuration as that of the first embodiment is omitted.

In this embodiment, an example in which the present invention is applied to a full-color image forming apparatus will be described.

As shown in FIG. 6, in the image forming apparatus of this embodiment, a Y station, an M station, a C station, and a K station for forming a toner image of each color are arranged in a horizontal direction. A toner image of each color is formed on the photosensitive drum 28 of each station in the same manner as described in the first embodiment, and the yellow, magenta, cyan, and black toner images are transferred by the transfer charger 23 of each station. The images are sequentially transferred onto the intermediate transfer belt 24B in a superimposed manner, and thereafter are collectively transferred onto the transfer paper 27 by the secondary transfer charger 23S.

In the intermediate transfer member system as in this embodiment, troubles such as paper jams are less likely to occur because the transfer mechanism of the transfer paper 27 is simplified, and various materials such as plain paper and OHP film can be easily applied. There are features such as being able to cope.

In the image forming apparatus of the present embodiment, the developer cartridges 5 corresponding to each station are arranged inside the intermediate transfer belt 24B. In the present embodiment, the connection between the supply port 6a and the developer supply screw 4 is on the near side of the intermediate transfer belt 24B, and the connection between the magnet 7 and the collection port 6b is on the front side of the intermediate transfer belt 24B. . Therefore, the transfer of the developer between the developing device 1 and the developer cartridge 5 does not hinder the running of the intermediate transfer belt 24B.

Another feature of this embodiment is that, as shown in FIG. 7, the rotation of the developer supply screw 4 and the magnet 7 are performed on the same drive shaft. Therefore, the drive mechanism has a simpler configuration than the first and second embodiments. Further, in this configuration, since the direction of the increase / decrease of the amount of the replenished developer and the amount of the recovered amount coincide, the amount of the developer in the developing container 2 is more stable, which is preferable.

Although the image forming apparatuses according to the first to third embodiments of the present invention have been described, the present invention is not limited to the above-described configuration, and various modifications are possible in accordance with the proposals of the present invention. Configurations are possible.

For example, in the first to third embodiments, the developer in the developing container 2 is directly collected by the magnet 7, but a part of the wall surface of the developing container 2 is cut out, and the cut is performed. The object of the present invention can be achieved without complicating the configuration, even if the configuration is such that the developer is collected from the portion containing the developer overflowing from the notch by the magnet 7 or the like.

[0063]

As described above, according to the invention of the present application, the developer in the developer container can be used in a single-color image forming apparatus or a full-color image forming apparatus having various configurations including a tandem system. Maintainability can be improved by gradually and automatically exchanging, and maintainability can be improved at low cost by adopting a simple configuration.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of a developer replenishing and collecting unit provided in the image forming apparatus of FIG.

FIG. 3 is a sectional view illustrating a schematic configuration of a developer replenishing and collecting unit provided in the image forming apparatus of FIG. 1;

FIG. 4 is a schematic sectional view schematically showing an image forming apparatus according to a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a developer replenishing and collecting unit provided in the image forming apparatus of FIG. 4;

FIG. 6 is a schematic sectional view schematically showing an image forming apparatus according to a third embodiment of the present invention.

FIG. 7 is a vertical sectional view of a developer replenishing and collecting unit provided in the image forming apparatus of FIG. 6;

FIG. 8 is a schematic sectional view showing a schematic configuration of a conventional image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Developing device (developing device) 1Y, 1M, 1C, 1K Developing device (developing device) 2 Developing container (developer container) 4 Developer supply screw (developer replenishing means) 5a Replenished developer accommodating part (replenished developer accommodating part) Container 5b Collected developer container (collected developer container) 6b Collection port (opening) 7 Magnet (magnetic field generator) 8 Scraper (peeling member) 23 Transfer charger (transfer unit) 23S Secondary transfer charger ( Transfer unit) 24B Intermediate transfer belt (transfer member) 27 Recording paper (recording medium) 28 Photosensitive drum (latent image carrier) 28B Photosensitive belt (latent image carrier) 28Y, 28M, 28C, 28K Photosensitive belt (latent image carrier) )

Claims (8)

[Claims] 1. A replenishment developer storage means capable of replenishing a new developer in a developer container for storing a two-component developer containing a toner and a magnetic carrier, and a degraded developer in the developer container being recoverable. And a developer capable of replacing the deteriorated developer in the developer container with new developer by replenishing the developer in the replenishment developer storage means and collecting the developer in the recovery developer storage means. Replenishing and collecting means, wherein the replenishing developer accommodating means comprises: a replenishing developer accommodating container for accommodating a developer to be replenished in the developer container; and a developer in the replenishing developer accommodating container. A developer replenishing means capable of replenishing the developer, the collected developer accommodating means includes a developer retrieving means capable of retrieving the developer from inside the developer container, and a collected developer accommodating container accommodating the developer. Supply and recovery The developer container and the collected developer container are integrally formed and disposed substantially above the developer container, and the developer collection means collects and holds the developer from the developer container by generating a magnetic field. A magnetic field generator supported on a surface and rotatable around an axis, and peeling close to, in contact with, or in pressure contact with the surface of the magnetic field generator so that the developer on the surface of the magnetic field generator is peeled off and collected in a collection developer container. And a member. 2. The collected developer container has an opening for collecting the collected developer by the magnetic field generator into the collected developer container, and the peeling member has at least one of the edges of the opening. 2. The developer replenishing and recovering unit according to claim 1, wherein the developer replenishing and collecting unit is formed integrally with the unit. 3. The developer replenishing means is capable of replenishing the developer contained in the collected developer containing container into the developer container by rotating the developer, and driving the magnetic field generator and the developer replenishing means. 3. The developer replenishing and collecting means according to claim 1, wherein the source is the same. 4. The developer supply and recovery means according to claim 3, wherein the magnetic field generator is supported on the same shaft as the developer supply means. 5. A developing device for visualizing a latent image as a developer image by applying a developer to a latent image carrier for carrying a latent image, comprising a two-component developer containing a toner and a magnetic carrier. A developing device comprising: a developer container to be accommodated; and the developer supply / recovery unit according to claim 1. 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: a latent image carrier for carrying a latent image; a developing device according to claim 5; and a transfer unit for transferring a developer image on the latent image carrier to a recording medium. 7. A plurality of developing devices are arranged in a substantially horizontal direction, and the latent image carrier is a rotatable endless belt-shaped photoconductor carrying a latent image on an outer peripheral surface thereof. 7. The image forming apparatus according to claim 6, wherein the developer supply and recovery unit is disposed along the inner peripheral surface of the photoconductor, and the developer supply and recovery unit is disposed above each of the developing devices. 8. The latent image carrier and the developing device form at least an image forming station including the latent image carrier and a plurality of the image forming stations are arranged in a substantially horizontal direction. A rotatable endless belt-shaped transfer member that carries the transferred developer image on the outer peripheral surface in order,
7. The image forming apparatus according to claim 6, wherein an outer peripheral surface of the transfer body faces each latent image carrier above each latent image carrier, and a developer supply / recovery unit is provided along an inner peripheral surface of the transfer body. The image forming apparatus as described in the above.