JPH09269655A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of keeping the inside of a developing rotary in a stabilized state for processing, by preventing pollution of the inside of the device due to scattering of toner for a developing device, and protecting the developing rotary from outside factors (steam, heat, oil and so on). SOLUTION: In the image forming device, supporting plural developing device 20Y, 20M and 20C, and locating the desired developing device (20Y, 20M and 20C) on a prescribed developing position so as to provide it for developing, the whole developing rotary 23 is covered by a cover 40. In such a manner, the toner leaked or scattered in the developing rotary 23 at the image forming time and at the rotating time of the developing rotary 23 is prevented from leaking or scattering outside by the cover 40, the pollution of the device inside by the scattering toner is restrained, and in the same time the developing rotary 23 can be protected from the outside factors (steam, heat, oil and so on) by the cover 40, therefore the developing rotary 23 inside can be kept in the stabilized state for processing.

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 printer or a copying machine using electrophotographic technology.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus for forming a color image is equipped with two or more developing devices, but a rotary unit equipped with two or more developing devices (hereinafter referred to as developing rotary) is It was not covered with a cover etc.

[0003]

However, when the developing rotary is not covered with a cover or the like as in the prior art, the toner in the developing device is scattered by the rotation of the developing rotary and the inside of the device is contaminated with the toner. There was a problem that Further, when the fixing device is installed near the developing rotary, there is a problem that the developing rotary is damaged by heat, water vapor or the like generated in the fixing device.

Further, there is a problem that the toner or the developing roller in the developing unit of the developing rotary is contaminated by the scattering of the lubricating oil or the like from other units.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent the inside of the machine from being contaminated by the toner scattered from the developing device and to prevent external factors (steam,
An object of the present invention is to provide an image forming apparatus capable of maintaining a stable process inside the developing rotary by protecting the developing rotary from heat, oil, etc.).

[0006]

In order to achieve the above object, the invention according to claim 1 supports a plurality of developing devices and rotates them about one axis to position a desired developing device at a predetermined developing position. In the image forming apparatus adapted to be used for development, the entire development rotary is covered with a cover.

According to a second aspect of the present invention, in the first aspect of the invention, the developing device is detachable from the developing rotary.

According to a third aspect of the invention, in the first or second aspect of the invention, the cover is independent of the developing rotary and is fixed to the main body of the image forming apparatus. To do.

According to a fourth aspect of the present invention, in the first, second or third aspect of the invention, the cover is made of resin.

[0010] The invention according to claim 5 is the invention according to claims 1, 2, 3
Alternatively, in the invention described in 4, the removable tray is provided below the cover.

According to a sixth aspect of the invention, in the fifth aspect of the invention, the tray is removable from the front side of the image forming apparatus main body.

The invention according to claim 7 is the invention as claimed in claims 1, 2, and 3.
Alternatively, in the invention described in item 4, an inclined groove inclined along the rotation center axis direction of the developing rotary is formed on the bottom surface of the cover.

The invention of claim 8 is the invention of claims 1, 2, and 3.
Alternatively, the invention described in 4 is characterized in that a fan for drawing air in the cover is provided at one end of the cover.

Therefore, according to the present invention, since the entire developing rotary is covered with the cover, the cover prevents the toner leaked or scattered inside the developing rotary during image formation and rotation of the developing rotary from leaking or scattering to the outside. The inside of the developing rotary can be protected from external factors (steam, heat, oil, etc.) and the inside of the developing rotary can be kept in a stable state in the process while preventing the contamination of the inside of the developing machine by the scattered toner. .

[0015]

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

<First Embodiment> [Description of Entire Image Forming Apparatus] First, an overall configuration of a color image forming apparatus will be outlined with reference to FIG. 1 is a sectional view of a color laser printer which is one form of the color image forming apparatus.

The color laser printer shown in FIG. 1 has an image carrier 15 rotating at a constant speed, a fixed black developing device 21B, and three rotatable color developing devices 20Y, 20M, 20.
A transfer material 2 which has an image forming portion constituted by C and multiple-transfers the color image developed in the image forming portion to the transfer material 2 fed from the feeding portion and receives the transfer of the color image.
Is transferred to the fixing device 25 to fix the color image on the transfer material 2, and the transfer material 2 on which the color image is fixed is discharged to the discharge roller 3
4 to 36, the sheet is discharged to the discharge section 37 on the upper surface of the apparatus. Incidentally, the rotatable color developing devices 20Y, 20
The M, 20C and the fixed black developing device 21B are configured to be individually attachable to and detachable from the printer body.

Next, the structure of each part of the color laser printer will be sequentially described in detail.

[Image bearing unit] Image bearing unit 1
An image carrier 3 (photosensitive drum) 15 and a cleaner container 14 that also serves as a holder for the image carrier 15 are integrally configured. The image carrier unit 13 is detachably supported on the printer body, and the image carrier 15
The unit can be easily replaced according to the life of the unit.

The image carrier 15 according to the present embodiment is constructed by coating an organic photoconductive layer on the outside of an aluminum cylinder, which is rotatably attached to the cleaner container 14 which also serves as a holder for the image carrier 15. It is supported. A cleaner blade 16 and a primary charging unit 17 are arranged on the periphery of the image carrier 15, and by transmitting the driving force of a drive motor (not shown) on the back side of FIG.
The image carrier 15 is rotationally driven in the direction of the arrow (counterclockwise direction) in accordance with the image forming operation.

[Charging Means] The primary charging means 17 employs a contact charging system, and a conductive roller is brought into contact with the image carrier 15 and a voltage is applied to the conductive roller to carry the image carrier. The surface of the body 15 is uniformly charged.

[Exposure Means] The image bearing member 15 is exposed by the scanner unit 30. That is, when the image signal is given to the laser diode, the laser diode irradiates the polygon mirror 31 with the image light corresponding to the image signal.

The polygon mirror 31 is rotated at a high speed by a scanner motor, and the image light reflected by the polygon mirror 31 is selectively rotated on the surface of the image carrier 15 through the imaging lens 32 and the reflection mirror 33 at a constant speed. , And as a result, an electrostatic latent image is formed on the image carrier 15.

[Developing Means] The developing means comprises three rotary developing devices 20 capable of developing each color of yellow, magenta, cyan and black in order to visualize the electrostatic latent image.
It is composed of Y, 20M, 20C and one black developing device 21B.

The black developing device 21B is a fixed developing device,
In the black developing device 21B, a sleeve 21BS is arranged at a position facing the image bearing member 15 with a minute gap with respect to the image bearing member 15.
5 forms a visible image with black toner.

That is, the black developing device 21B feeds the toner in the container by the feeding mechanism, and applies a thin layer of toner on the outer circumference of the sleeve 21BS rotating clockwise in the drawing by the application blade 21BB pressed against the outer circumference of the sleeve 21BS. At the same time, an electric charge is applied to the toner (friction charging). Then, by applying a developing bias to the sleeve 21BS, toner development is performed corresponding to the electrostatic latent image on the image carrier 15.

Further, three rotary developing devices 20Y, 20M, 2
0C is a development rotary 2 that rotates about the axis 22.
3 are detachably held, and at the time of image formation, the developing devices 20Y, 20M, and 20C are rotationally moved about the shaft 22 while being held by the developing rotary 23, and the predetermined developing devices (20Y, 20M, 20C) is the image carrier 15
Stand still at the position corresponding to the
S, 20MS, 20CS) are positioned so as to face the image carrier 15 with a minute interval (about 300 μm), and then a visible image is formed corresponding to the electrostatic latent image of the image carrier 15. When forming a color image, the developing rotary 23 rotates for each rotation of the intermediate transfer member 9, and the yellow developing device 20Y, the magenta developing device 20M, and the cyan developing device 20 are rotated.
The developing process is performed in the order of C and then the black developing device 21B.

FIG. 1 shows a state in which the yellow rotary developing device 20Y is positioned at a position corresponding to the image carrier 15 and is stationary. In this state, the toner in the container of the rotary developing device 20Y is in a stationary state. Is fed to the coating roller 20YR by the feeding mechanism, and is applied in a thin layer on the outer periphery of the developing roller 20YS rotating clockwise in the drawing by the coating roller 20YR rotating clockwise in the drawing and the blade 20YB pressed against the outer periphery of the developing roller 20YS. A predetermined charge is applied (triboelectric charging).

By applying a developing bias to the developing roller 20YS facing the image carrier 15 on which the latent image is formed, toner development is performed on the image carrier 15 according to the latent image. Then, toner development is also performed on the magenta developing unit 20M and the cyan developing unit 20C by the same mechanism as described above.

The rotary developing devices 20Y, 20M, 20C
The developing rollers 20YS, 20MS, 20CS are connected to the developing high-voltage power supplies and drives provided in the printer main body when the developing units 20Y, 20M, 20C are rotated to the developing position, and for each color developing. A voltage is applied selectively and sequentially, and a drive is connected.

[Intermediate Transfer Member] The intermediate transfer member 9 is used in each of the developing devices 20Y, 20M and 20 during a color image forming operation.
The toner image on the image carrier 15 visualized by C and 21B is subjected to multiple transfer for four times (four color images of yellow, magenta, cyan, and black), so that the toner image is synchronized with the outer peripheral speed of the image carrier 15. Is rotated in the direction of the arrow (clockwise) shown in the figure, and the intermediate transfer body 9 that has undergone multiple transfer is sandwiched with the transfer roller 10 to which a voltage is applied and the transfer material 2 is conveyed and transferred to the transfer material 2. The formed toner images of respective colors are simultaneously and multiple-transferred onto the transfer material 2.

The intermediate transfer member 9 according to the present embodiment is
The outer circumference of the aluminum cylinder 12 is covered with an elastic layer 11 such as a medium resistance sponge or medium resistance rubber. The intermediate transfer body 9 is rotatably supported and is rotated by being driven by a gear (not shown) integrally fixed to the intermediate transfer body 9.

[Cleaning Means] The cleaning means cleans the toner remaining on the image carrier 15 after the toner image visualized on the image carrier 15 by the developing means is transferred to the intermediate transfer body 9. The cleaned waste toner is stored in the cleaner container 14.
The amount of waste toner stored in the cleaner container 14 does not fill the cleaner container 14 earlier than the life of the image carrier 15, and therefore the cleaner container 14 is integrally replaced at the same time when the life of the image carrier 15 is replaced. To be done.

[Paper Feed Unit] The paper feed unit transfers the transfer material 2 to the image forming unit.
For feeding a plurality of transfer materials 2, a sheet feeding roller 3, a feeding roller 4, a retard roller 5 for preventing double feeding, a sheet feeding guide 6, a conveying roller 7, and a resist. It is composed of rollers 8 and the like.

During image formation, the paper feed roller 3 is driven to rotate in accordance with the image forming operation, and the paper feed roller 3 separates and feeds the transfer materials 2 in the cassette 1 one by one. Then, the transfer material 2 is guided by the paper feed guide 6 and reaches the registration roller 8 via the transport roller 7. During the image forming operation, the registration roller 8 performs a non-rotating operation of keeping the transfer material 2 stationary and a rotating operation of transporting the transfer material 2 toward the intermediate transfer body 9 in a predetermined sequence, and is a next step. The image and the transfer material 2 at the time of the transfer step are aligned.

[Transfer Section] The transfer section is composed of a swingable transfer roller 10. The transfer roller 10 is composed of a metal shaft wound with a medium resistance foamed elastic body and is movable up and down in the drawing. , Receives a drive and rotates.

By the way, while the toner images of four colors are formed on the intermediate transfer member 9, that is, while the intermediate transfer member 9 is rotated a plurality of times, the image is shown by a solid line so as not to disturb the image. Thus, the transfer roller 10 is located below and the intermediate transfer member 9
Away from.

After the toner images of four colors have been formed on the intermediate transfer member 9, the transfer roller 10 is moved by a cam member (not shown) at the timing of transferring the color image onto the transfer material 2. It is moved to the upper position shown by the chain line, and is pressed against the intermediate transfer body 9 via the transfer material 2 with a predetermined pressure. At this time, a bias is simultaneously applied to the transfer roller 10, and the toner image on the intermediate transfer body 9 is transferred to the transfer material 2.

Here, since the intermediate transfer body 9 and the transfer roller 10 are driven respectively, the transfer material 2 sandwiched between the two is subjected to the transfer process and at the same time, is moved to the left in FIG. It is conveyed at a speed and is sent toward the fixing device 25 where the next step is carried out.

[Fixing Section] The fixing device 25 is for fixing the toner image transferred onto the transfer material 2 onto the transfer material 2, and as shown in FIG. 1, for applying heat to the transfer material 2. It is composed of a fixing roller 26 and a pressure roller 27 for pressing the transfer material 2 to the fixing roller 26. Each of the rollers 26, 27 is a hollow roller, and heaters 28, 29 are built therein. Then, both rollers 26 and 27 are rotationally driven to convey the transfer material 2. It is configured as follows. Therefore, the transfer material 2 carrying the toner image is conveyed by the fixing roller 26 and the pressure roller 27, and
The toner image is fixed by applying heat and pressure.

[Image Forming Operation] Next, the image forming operation of the color laser printer configured as described above will be described.

First, the paper feed roller 3 shown in FIG. 1 is rotationally driven to separate one transfer material 2 in the paper feed cassette 1 and convey it to the registration roller 8.

On the other hand, the image carrier 15 and the intermediate transfer member 9 are rotationally driven in the direction of the arrow in the figure at a predetermined outer peripheral speed (process speed).

As shown in FIG. 2, when an arbitrary point on the outer circumference of the intermediate transfer member 9 reaches the position S in the drawing, the primary charging means 17
The image carrier 15 whose surface has been uniformly charged by the above is subjected to laser exposure at the position of arrow E in FIG. 2, and an electrostatic latent image is formed on the image carrier 15. Here, the distance a from the exposure position E of the image carrier 15 counterclockwise to the contact portion T1 with the intermediate transfer body 9 and the distance b from the point S to T1 in the figure of the intermediate transfer body 9 are equal, and therefore the time After the lapse of time, the point E at the beginning of writing the image and the point S on the intermediate transfer body 9 coincide at the position T1. That is, the electrostatic latent image is formed counterclockwise on the intermediate transfer body 9 with the point S as the tip.

1) Formation of yellow image; scanner unit 30
Thus, laser irradiation of a yellow image is performed on the image carrier 15 to form a yellow latent image on the image carrier 15. Simultaneously with the formation of this latent image, the yellow developing device 20Y is driven to apply a voltage of substantially the same potential as the charging polarity of the image carrier 15 to the sleeve 20YS so that the yellow toner adheres to the latent image on the image carrier 15. It is applied to perform yellow development. At the same time, at the first transfer position T1 slightly downstream of the developing unit, the image carrier 1
The yellow toner image on 5 is primarily transferred to the outer periphery of the intermediate transfer body 9. At this time, a voltage having a characteristic opposite to that of the yellow toner is applied to the intermediate transfer body 9.

When the image to be formed is, for example, A3 size,
An image is formed between the point S1 and the point L1 on the outer periphery of the intermediate transfer body 9 (see the thick line on the outer periphery of the intermediate transfer body 9 in FIG. 2). When the transfer of the yellow toner onto the intermediate transfer body 9 is completed, that is,
When L1 passes the first transfer position T1, the developing rotary 2
3 rotates clockwise, the next magenta developing device 20M rotationally moves, and the magenta developing device 20M is positioned at a position facing the image carrier 15.

2) Formation of magenta image: When a point S (front end of the yellow image) on the outer periphery of the intermediate transfer member 9 makes one round and reaches the position S in the drawing, the scanner section 30 similarly causes a laser of the magenta image to be formed. Irradiation is started, a magenta toner image is developed on the latent image on the image carrier 15 in the same manner as yellow, and the magenta toner image on the image carrier 15 is first developed.
Similarly, the image is transferred onto the intermediate transfer member 9 at the transfer position T1. When the transfer of the magenta toner image to the intermediate transfer body 9 is completed, that is, when the point L1 passes the first transfer position T1, the developing rotary 23 rotates clockwise and the next cyan developing device 20C rotationally moves. Then, the cyan developing device 20C is positioned at a position facing the image carrier 15.

3) Formation of a cyan image; then, a point S on the outer periphery of the intermediate transfer member 9 (the tip of the yellow and magenta images)
When the image has reached the position S in the figure after one more rotation, the laser irradiation of the cyan image is similarly started by the scanner unit 30, and the cyan toner image is developed on the latent image on the image carrier 15 in the same manner as magenta. The cyan toner image on the image carrier 15 is transferred onto the intermediate transfer member 9 at the first transfer position T1 so as to be superimposed on the yellow and magenta toner images. When the transfer of the cyan toner image to the intermediate transfer body 9 is completed, that is,
When L1 passes the first transfer position T1, the developing rotary 2
3 rotates clockwise by 60 degrees, and the color developing units 20Y, 20M, and 20C are not present at the positions facing the image carrier 15.

4) Formation of black image; when a point S (front end of yellow, magenta, and cyan images) on the outer periphery of the intermediate transfer member 9 makes another round and reaches the position S shown in the figure, the scanner section 30 is also used. Laser irradiation of the black image is started, then the black toner image is developed by the black developing device 21B, and the black toner image on the image carrier 15 is further transferred onto the intermediate transfer member 9 at the first transfer position T1.

As described above, latent image formation and development in the order of yellow, magenta, cyan, and black and transfer of the toner image to the intermediate transfer body 9 are sequentially performed four times, and yellow, magenta, cyan, and cyan are formed on the surface of the intermediate transfer body 9. A full color image composed of four types of black toner is formed.

Before the transfer of the black toner to the intermediate transfer body 9 is completed, that is, the first transfer of the fourth black toner image is completed and the image front end S of the intermediate transfer body 9 on which the full color image is formed is transferred to the second transfer. Before reaching the section T2, the transfer material 2 which has been waiting by the above-mentioned registration roller 8 is conveyed at the same timing.

At the time of forming each color image on the intermediate transfer member 9 four times, the transfer roller 10 which is not in contact with the intermediate transfer member 9 is simultaneously moved to the upper position by a cam (not shown) at the same time. By pressing the transfer material 2 at the second transfer portion T2 of the intermediate transfer body 9 and simultaneously applying a bias having a polarity opposite to that of the toner to the transfer roller 10, a full color image on the intermediate transfer body 9 is transferred to the transfer material 2 in four colors at once. Simultaneous transcription. Then, the transfer material 2 that has passed through the second transfer portion T2 is peeled from the intermediate transfer body 9 and conveyed to the fixing device 25, and after receiving the fixing of the full-color image, the discharge rollers 34 to 36 discharge the discharge material 37 at the upper part of the main body. The image is discharged upward with its image surface facing downward, and a series of image forming operation images ends here.

Next, the gist of the present invention will be described with reference to FIGS. 3 is an enlarged cross-sectional view of the developing rotary 23 portion of the color laser printer shown in FIGS. 1 and 2.
FIG. 4 is a perspective view showing a part of a cover covering the developing rotary 23 in a cutaway manner.

In FIGS. 3 and 4, reference numeral 40 is a cover which covers the entire developing rotary 23 which is mounted with the three rotary developing devices 20Y, 20M and 20C and rotates. The cover 40 has a cylindrical shape with both ends open, and has rectangular openings 40A and 40B, which are long in the generatrix direction, on its side surface.
Are formed. The cover 40 is integrally formed of resin, which is independent of the developing rotary 23 and is fixed to the printer body.

A tray 41 is provided below the cover 40, and the tray 41 can be inserted and removed in the direction of the arrow in FIG. Then, cover the tray 41 with the cover 40.
When it is attached to the tray 41,
It is constituted so that it may open. The other opening 40B formed in the cover 40 is for bringing the developing sleeves 20YS, 20MS, 20CS into contact with the image carrier 15.

Thus, when the image forming operation is performed as described above, toner scattering and leakage occur, but in the present embodiment, the entire developing rotary 23 including the rotary developing units 20Y, 20M and 20C is covered. Since the toner is scattered by the cover 40, the toner scattered inside the cover 40 does not leak to the outside of the cover 40, and the toner leaked or scattered inside the cover 40 remains inside the cover 40, and the toner scattered inside the machine Is never contaminated.

After that, the scattered toner remaining in the cover 40 gathers in the lower part of the cover 40 due to its own weight, and as described above, the opening 40A is formed in the lowermost part of the cover 40.
Therefore, the toner is accumulated in the tray 41 through the opening 40A. Then, when the toner has accumulated in the tray 41 to some extent, the user can hold the handle 41A and pull out the tray 41 to the front surface of the printer main body as shown in FIG. 4 to discard the toner accumulated in the tray 41.

Further, as described above, the cover 40 not only prevents the scattered toner generated inside the cover 40 from scattering to the outside, but also leaks the toner leaked from the black developing device 21B disposed above the developing rotary 23. And color developing devices 20Y, 20
Prevents M and 20C from getting dirty, and the development rotary 23
Of the color developing device 20 due to water vapor generated from the fixing device 25 located below the fixing device and oil scattered from the fixing device 25.
It also functions to prevent Y, 20M, and 20C from becoming dirty. In addition, the cover 40 also exhibits a heat insulating effect against heat generated from the fixing device 25.

<Second Embodiment> Next, an embodiment of the present invention will be described with reference to FIG. FIG. 5 is a perspective view of the cover according to the second embodiment of the present invention.

In the first embodiment, the tray 41 is provided in the lower portion of the cover 40, but in the present embodiment, the inclined groove 45A is formed in the lower portion of the cover 45 along the longitudinal direction.

Thus, in the present embodiment, the toner gathered in the lower portion of the cover 45 flows along the inclined groove 45A, and finally falls in the direction of arrow a to drop the waste toner box 46.
The waste toner is collected inside and the user can process the waste toner by replacing the waste toner box 46. In this way, by disposing the waste toner box 46 on the outside of the cover 45, the size, shape, etc. of the waste toner box 46 can be freely set.

<Third Embodiment> Next, an embodiment of the present invention will be described with reference to FIG. 6 is a perspective view of the cover according to the third embodiment of the present invention.

In the present embodiment, the dustproof filter 47 and the fan 48 are arranged at one end of the cover 49, and the fan 48 is
By this, the air inside the cover 49 is forcibly produced outside the cover 49.

Thus, according to the present embodiment, the cover 4
The toner scattered in 9 can be collected by the dustproof filter 47. That is, as shown by the arrow in FIG. 6, the dirty air 51A can be discharged as clean air 51B. If the dustproof filter 47 is replaced when it becomes dirty, the cleaning ability is restored. Further, by adopting such a configuration, the inside of the cover 49 can be cooled, and a better condition for the developing device can be maintained.

[0065]

As is apparent from the above description, according to the present invention, since the entire developing rotary is covered with the cover, the toner leaked or scattered inside the developing rotary during image formation and rotation of the developing rotary is exposed to the outside. Leakage and scattering are prevented by the cover, and contamination inside the machine by scattered toner is prevented, and the cover can protect the developing rotary from external factors (water vapor, heat, oil, etc.), and the inside of the developing rotary can be processed. The effect that can be maintained in a stable state is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an image forming apparatus (color laser printer) according to the present invention.

FIG. 2 is a sectional view of an image forming apparatus (color laser printer) according to the present invention.

FIG. 3 is an enlarged sectional view of a developing rotary portion of the image forming apparatus (color laser printer) according to the present invention.

FIG. 4 is a perspective view showing a cover according to the first embodiment of the present invention with a part thereof cut away.

FIG. 5 is a perspective view of a cover according to the second embodiment of the present invention.

FIG. 6 is a perspective view of a cover according to a third embodiment of the present invention.

[Explanation of symbols]

 20Y, 20M, 20C Developing device 22 Shaft 23 Developing rotary 40, 45, 49 Cover 41 Tray 45A Inclined groove 48 Fan

Claims (8)

[Claims] 1. An image forming apparatus which supports a plurality of developing devices and rotates about a single axis to position a desired developing device at a predetermined developing position for use in development. An image forming apparatus characterized in that a cover is covered. 2. The image forming apparatus according to claim 1, wherein the developing device is attachable to and detachable from the developing rotary. 3. The image forming apparatus according to claim 1, wherein the cover is independent of the developing rotary and is fixed to the main body of the image forming apparatus. 4. The image forming apparatus according to claim 1, wherein the cover is made of resin. 5. The image forming apparatus according to claim 1, wherein a detachable tray is provided below the cover. 6. The image forming apparatus according to claim 5, wherein the tray is detachable from the front side of the image forming apparatus main body. 7. The image forming apparatus according to claim 1, wherein an inclined groove is formed on the bottom surface of the cover so as to incline along the direction of the rotation center axis of the developing rotary. 8. The image forming apparatus according to claim 1, wherein a fan for drawing air inside the cover is provided at one end of the cover.