JP2003345118A - Developing device for electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently transport toner to a developing device from a toner container disposed apart. <P>SOLUTION: A toner transport means which supplies toner from a side of a mixing means for toner in a developing tank is disposed between a toner storage means and the developing tank. Thus, the toner container can be disposed in the optimum position in view of space. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device in an electrophotographic apparatus used in a copying machine, a printer, a facsimile, a composite machine of them, and more particularly to a developing tank having a mixing means for stirring a developer and a developing roller. In an electrophotographic apparatus having a developing device in which the toner is supplied from a toner storage means such as a toner container, a developing device in the electrophotographic device in which space can be effectively used. is there.

[0002]

2. Description of the Related Art Recently, electrophotographic apparatuses used in copying machines, printers, facsimiles, and their multi-function machines have been required to be smaller and less expensive in response to the demand for personalization. However, for example, a color electrophotographic apparatus in which a developing unit corresponding to a plurality of colors having a mixing unit for stirring a developer and a developing roller is arranged around the photoconductor and toner is supplied from a toner container to each developing unit. In the above, even if the photoconductor is downsized in response to the request for downsizing of the electrophotographic apparatus, the toner storage means such as the toner container for supplying the toner to the developing tank of each color is large, so that the space cannot be effectively used, There arises a problem that the electrophotographic apparatus itself cannot be downsized.

That is, a developing device in an electrophotographic apparatus used in a copying machine, a printer, a facsimile, a composite machine thereof, or the like uses a toner container for replenishing toner consumed by image formation. It is necessary to mix and agitate the toner replenished from the container, the developer in the developing tank, and the toner remaining on the photoconductor without being transferred to the recording medium and further appropriately charging. Therefore, for example, JP-A-8-50405, JP-A-10-69155, and JP-A-10-1
No. 98148 discloses various developer transport devices for mixing the replenished toner, the developer in the developing tank, and the toner remaining on the photosensitive member without being transferred to the recording medium or the intermediate transfer member. A developing device provided with a stirring device has been proposed.

To replenish the toner from the toner container, the developer in the developing tank or the toner remaining on the photosensitive member and the replenished toner are well mixed with each other by a mixer arranged in the developing tank. It is preferable that the toner container supply port is directly above. That is, when the toner is supplied to a position away from the mixer, a toner pool is formed, and the toner remains without being stirred for a long time to deteriorate or solidify, or an image defect occurs due to development with a developer having a low toner concentration. Occur. Therefore, as shown in FIG. 7, the conventional developing device has a mixer 7 for stirring the developer.
It is general that the toner container 73 is arranged on the developing tank 72 having 0 or the developing roller 71, and the toner supply port 74 is located immediately above the mixer 70.

[0005]

However, the volume of this toner container is relatively large, and as described above, the developing tanks of the respective colors are arranged around the miniaturized photoconductor in response to the demand for miniaturization of the electrophotographic apparatus. In a color electrophotographic apparatus, if a toner container for supplying toner is arranged just above a mixer in a developing tank, a large space is required above the developing tank, and the electrophotographic apparatus itself becomes large. Cause However, the above-mentioned JP-A-8-50405 and JP-A-10-
The apparatus disclosed in Japanese Patent No. 69155, Japanese Patent Laid-Open No. 10-198148, etc. does not suggest how to deal with such problems.

Therefore, in the present invention, the space in the electrophotographic apparatus is effectively used, and the supplied toner is not transferred to the developer in the developing tank, the recording medium or the intermediate transfer member and is transferred onto the photosensitive member. An object of the present invention is to provide a developing device in an electrophotographic apparatus having a simple and inexpensive structure that can surely mix and stir with the remaining toner.

[0007]

Therefore, in the present invention, as described in claims 1 and 2, it is arranged around a photosensitive member carrying an electrophotographic latent image and has a developer mixing means. A developing device in an electrophotographic apparatus having a developing tank, a developing roller arranged at a position facing the photoconductor of the developing tank for developing the latent image, and a toner storing means for supplying toner to the developing tank. In the above, there is provided a toner conveying means which is arranged between the toner storing means and the developing tank and supplies toner from a side of the developing tank facing the developing roller. And claim 2
Is arranged around a photoconductor carrying a latent image by an electrophotographic method, and has a developing tank corresponding to each color having a developer mixing device, and a photoconductor in the developing tank for developing the latent image. In a developing device in an electrophotographic apparatus having a developing roller arranged at a predetermined position, and a toner storing means for supplying toner to each of the developing tanks, at least one toner storing means and corresponding toner storing means It is characterized in that it is provided between the developing tank and a toner conveying means for supplying toner from a side of the developing tank facing the developing roller.

In this way, from the toner storage means to the developing tank,
By providing the toner conveying means for supplying the toner from the side of the developing tank facing the developing roller, it is not necessary to position the toner storing means above the developing tank, and the toner storing means is installed at a position distant from the developing tank. Therefore, it is possible to provide a developing device in an electrophotographic apparatus having a simple and inexpensive structure, which effectively utilizes the space in the electrophotographic apparatus.

According to the third aspect of the present invention and the fourth aspect of the invention, the toner conveying means supplies the conveyed toner to the upper side of the toner in the developing tank. Characterize. The means for supplying the conveyed toner in the toner conveying means to the upper side of the toner in the developing tank is an overflow means provided between the toner conveying means and the mixing means.

As described above, by supplying the conveyed toner from above the toner in the developing tank, the supplied toner and the developer in the developing tank, and the photosensitive material without being transferred to the recording medium or the intermediate transfer member are exposed. The toner remaining on the body can be surely mixed and stirred, and the same effect as the case where the toner storage means is provided above the conventional mixing means can be obtained, and the toner storage means is provided above the developing tank as described above. There is no need to position it, and since the toner storage means can be installed at a position away from the developing tank, it does not cause development defects and is easy,
It is possible to provide a developing device in an electrophotographic apparatus that has an inexpensive structure and effectively utilizes the space in the electrophotographic apparatus.

The invention as set forth in claim 5 is characterized in that the toner storing means is provided above the toner conveying means.

By thus providing the toner storage means on the upper side of the toner transport means, it is not necessary to provide a special transport means from the toner storage means to the toner transport means, and the electrophotographic apparatus has a simple and inexpensive structure. It is possible to provide a developing device in an electrophotographic device that effectively utilizes space.

According to a sixth aspect of the present invention, the toner carrying means is provided in a direction orthogonal to the mixing means of the developing tank.

By thus providing the toner conveying means in the direction orthogonal to the mixing means, the toner accommodating means and the mixing means can be connected at the shortest distance, and the toner can be efficiently conveyed.

The invention according to claim 7 is characterized in that the toner carrying means operates when a toner concentration detecting device provided in the developing tank gives an instruction to supply toner.

By thus operating the toner conveying means when the toner concentration detecting device instructs the toner supply, it is possible to obtain an electrophotographic device which does not use extra electric power.

The invention according to claim 8 is characterized in that the toner conveying means operates in conjunction with a mixing means provided in the developing tank.

By operating the toner conveying means in conjunction with the mixing means in this way, a special driving means and a control circuit for operating the toner conveying means are unnecessary, and the electrophotographic apparatus is inexpensive accordingly. You can

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative positions, and the like of the constituent parts described in this embodiment are not intended to limit the scope of the present invention thereto, unless otherwise specified, and are merely It is only an example.

FIG. 1 is a schematic sectional view showing an arrangement of a developing tank and a toner container around a photosensitive drum in an embodiment of an electrophotographic apparatus having a developing device according to the present invention. FIG. 2 shows the present invention. FIG. 3 is a perspective view showing an example of a developing tank and a toner conveying path which constitute the developing device in the electrophotographic apparatus according to the present invention, and FIG. FIG. 5 is a perspective view of the toner transport path viewed from the side of the developing tank that constitutes the developing device of the electrophotographic apparatus according to the present invention. FIG. FIG. 6 is a perspective view of the embodiment, and FIG. 6 is a perspective view of the toner transport path viewed from the developing tank side which constitutes another embodiment of the developing device in the electrophotographic apparatus according to the present invention. Although a color electrophotographic apparatus will be described as an example in the following description, it is obvious that the present invention can be applied not only to a color electrophotographic apparatus but also to a monochrome electrophotographic apparatus.

In the figure, 1 is amorphous silicon (a-Si).
Abbreviated as "), an organic photoconductor drum (OPC), and the like, and 2 is a charger of the photoconductor drum 1 and 3 to
6 is a developing tank corresponding to each color of yellow (Y) 3, magenta (M) 4, cyan (C) 5, and black (K) 6, and 7 to 9 are toner containers as toner accommodating means.
Reference numeral 10 is a conveying means for conveying the toner from the toner container 9 to the developing tank 5, and 11 is an intermediate transfer body for transferring the toner image formed on the photosensitive drum 1.

2 to 6 show details of the cyan (C) developing tank and the toner container 9 indicated by reference numeral 5 in FIG. 1 and the carrying means 10 for carrying the toner from the toner container 9 to the developing tank 5 (FIGS. 2), a perspective view of the developing tank 5 and the carrying means 10 (FIG. 3), and a perspective view of the carrying means 10 as seen from the developing tank 5 side (FIG. 4), and FIGS.
Details of another embodiment of the cyan (C) developing tank and the toner container 9 and the carrying means 10 for carrying the toner from the toner container 9 to the developing tank 5 (see FIG. 5).
And a perspective view of the conveying means 10 as seen from the developing tank 5 side (FIG. 6)
Is. In the figure, 20 is a developing roller for carrying a developer to develop the latent image formed on the photosensitive drum 1, 21 is a mixing means for agitating the developer in the developing tank 5 to charge the toner, In this figure, as an example, a mixing means is shown in which spiral protrusions are arranged on both the hollow cylindrical body and the rotating body provided inside the hollow cylindrical body, and they are rotated in opposite directions to stir the developer. It was 22 is a toner concentration detection sensor for detecting the toner concentration of the developer in the developing tank 5,
Reference numeral 23 is a screw constituting the conveying means 10, 24 is a toner supply port of the toner container 9, 25 is toner, 26 is a bearing of the screw constituting the conveying means 10 on the developing tank 5 side,
Reference numeral 27 is a partition wall as overflow means provided between the toner conveying means 10 and the mixing means 21, and 28 is a toner replenishing roller.

In the present invention, as shown in FIGS. 1 to 4, at least one or more toner containers, for example, 9 and the developing tank 5 are connected by the toner conveying means 10.
The toner supply port of the toner conveying means 10 to the developing tank 5 is a side surface of the mixing means 21 on the side facing the developing roller in the developing tank 5. A screw 23 is arranged in the toner conveying means 10, and the toner dropped from the toner supply port 24 of the toner container 9 is supplied to the mixing means 21 of the developing tank 5 by the screw 23.

That is, as described above, the photosensitive drum 1
1 can be arranged in the developing tanks 3 to 6 for each color, as shown in FIG. 1, but all the toner containers 7 to 9 are arranged directly above the developing tanks 3 to 6 or in the developing tanks. When the toner can be supplied from above to the mixing means, it is necessary to dispose the toner container 9 or the toner container 8 further on the left side or the upper side in the drawing. It needs to be large. And if you do this,
It is necessary to connect the toner container and the developing tank with a toner conveying means, the number of parts is increased, and the control means for them are also required, which is expensive and the electrophotographic apparatus itself is large.

However, as described above, at least one or more toner containers, for example, 9 and the developing tank 5 are disposed between the toner conveying means 10, and the toner is supplied to the developing tank 5 of the toner conveying means 10. By setting the opening on the side surface of the mixing means 21 in the developing tank 5, that is, on the side of the developing tank 5 facing the developing roller 20, the toner container 9 does not need to be installed directly above the developing tank 5, and is apparent from FIG. As described above, the developing tank 4 can be arranged on the left side in the drawing with a spatial space without interfering with the developing tank 4. Therefore, the toner container 9 can be arranged by effectively utilizing the space without using complicated conveying means and control means, and the electrophotographic apparatus itself can be made compact.

The above is the developing device in the electrophotographic apparatus of the present invention. As shown in FIG. 2, the toner supply port of the toner conveying means 10 to the developing tank 5 is provided on the side facing the developing roller in the developing tank 5. When the bearing 26 of the screw 23 of the toner conveying means 10 is provided on the upper side as shown in FIG. 4, the toner 25 conveyed by the screw 23 of the toner conveying means 10 is provided.
May enter the lower side of the mixing means 21 as shown in FIG. 2, and may not be agitated well with the developer in the developing tank 5 or the toner remaining on the photosensitive drum 1 without being transferred to the intermediate transfer body 11. . Therefore, such a situation is dealt with in the second embodiment of the developing device in the electrophotographic apparatus of the present invention shown in FIG.

In the second embodiment shown in FIG. 5, the bearing of the screw 23 of the toner conveying means 10 is provided between the toner supplying port of the toner conveying means 10 to the developing tank 5 and the mixing means 21. At the same time, a partition wall 27 is provided as overflow means for overflowing the conveyed toner. That is, when the partition wall 27 as overflow means is provided in this way, the screw 23 of the toner conveying means 10 is provided.
The toner transported in the partition wall 2 as the overflow means.
When the toner is once dammed by 7 and a certain amount of toner is accumulated, the toner surmounts the partition wall 27, and the arrow 25 in FIGS.
As shown in FIG. 5, the toner is supplied from the upper surface side of the mixing means 21, and is supplied from the upper side of the developer in the developing tank 5. Therefore, this toner is surely agitated with the developer inside the developing tank 5 and the toner remaining on the photosensitive drum 1 without being transferred to the intermediate transfer member 11, and is not sufficiently agitated to be developed by the developer having a low toner concentration. Does not occur and an image defect does not occur.

The developing device in the electrophotographic apparatus according to the present invention has been described above. The toner conveying means 1 described above is used.
It is preferable that 0 is provided below the toner container 9 and in a direction orthogonal to the corresponding mixing means 21 of the developing tank 5. That is, by providing the toner conveying means 10 on the lower side of the toner container 9, the toner is simply supplied to the toner conveying means 10 by dropping the toner, and by providing the toner conveying means 10 in a direction orthogonal to the mixing means 21, The toner containing means 9 and the mixing means 21 can be connected at the shortest distance, and the toner can be efficiently conveyed. Further, the screw 23 of the toner conveying means 10 may be required to operate when the toner concentration detecting device 22 provided in the developing tank 5 gives an instruction to supply the toner, and is further interlocked with the mixing means 21 provided in the developing tank 5. You may make it operate. Toner transporting means 10
If the screw 23 is operated when the toner concentration detecting device 22 instructs the toner supply, unnecessary electric power is not used. On the other hand, when the screw 23 is operated in conjunction with the mixing means 21, the toner conveying means No special drive means or control circuit for operating the screw 23 of 10 is required, and the electrophotographic apparatus can be made inexpensive accordingly.

The operation of the electrophotographic apparatus having the developing device of the present invention will be briefly described below with reference to FIG. Now, when the image data to be printed is sent, the photoconductor drum 1 is first charged by the charger 2, and the image corresponding to each color is exposed on the photoconductor drum 1 by an optical scanning unit (not shown). , A latent image is formed on the exposed part (exposure part). After that, development is performed by the developing device of the color corresponding to the image of the exposed color in the developing device, and a toner image is formed. This toner image is primarily transferred to the intermediate transfer body 11 side at the nip portion where the photosensitive drum 1 and the intermediate transfer body 11 are in contact with each other by the primary transfer bias applied between the photosensitive drum 1 and the intermediate transfer body 11. Then, all the toner images of other colors are primarily transferred to the intermediate transfer body 11. And
When the toner images of all colors are primarily transferred to the intermediate transfer body 11, the recording medium is conveyed from a sheet feeding cassette (not shown), the toner images on the intermediate transfer body 11 are secondarily transferred, and the recording medium is fixed. A device (not shown) heats and pressurizes to fix the toner image on the recording medium and ejects the sheet.

During this time, the toner concentration detection sensor 22 provided in each of the developing tanks 3 to 6 detects the concentration of the developer, and when the toner concentration in the developer decreases due to the consumption of toner by the image forming operation, A signal is sent to a control circuit of an electrophotographic apparatus (not shown) to instruct to supply the toner from a toner container as a toner accommodating means corresponding to the developing tanks 3 to 6 in which the toner concentration is reduced, and the toner container is required A quantity of toner is supplied to the developing tank.
At the time of this supply, when an instruction is given to the toner container 9 corresponding to the developing tank 5, for example, the toner replenishing roller 28 in the toner container 9 facing the toner supply port 24 is rotated and the toner becomes toner. The toner that has fallen onto the conveying means 10 and has fallen onto the toner conveying means 10 is conveyed by the screw 23 to the mixing means 21 of the developing tank 5,
The mixing means 21 surely agitates the developer remaining in the developing tank 5 and the toner remaining on the photosensitive drum 1 without being transferred to the intermediate transfer body 11.

[0031]

As described above, according to the present invention as set forth in claims 1 and 2, there is provided toner conveying means for supplying toner from the toner storing means to the developing tank from the side of the developing tank facing the developing roller. By providing the toner storage means, it is not necessary to position the toner storage means on the upper part of the developing tank, and the toner storage means can be installed at a position distant from the developing tank. Therefore, the space in the electrophotographic apparatus is effectively used with a simple and inexpensive structure. A developing device in an electrophotographic apparatus can be provided.

According to the present invention as set forth in claims 3 and 4, by supplying the conveyed toner from above the toner in the developing tank, the supplied toner, the developer in the developing tank, and the recording are recorded. The toner remaining on the photosensitive member without being transferred to the medium or the intermediate transfer member can be surely mixed and stirred, and the same effect as in the case where the toner storage unit is provided above the conventional mixing unit is obtained, and It is not necessary to position the toner storage means on the upper side of the developing tank as described above, and the toner storage means can be installed at a position apart from the developing tank. It is possible to provide a developing device in an electrophotographic device that effectively utilizes the space in the device.

According to the present invention described in claim 5, by providing the toner storing means on the upper side of the toner conveying means, it is not necessary to provide a special conveying means from the toner storing means to the toner conveying means, and it is simple. Thus, it is possible to provide a developing device in an electrophotographic apparatus which has an inexpensive structure and effectively utilizes the space in the electrophotographic apparatus.

According to the present invention described in claim 6, by providing the toner conveying means in the direction orthogonal to the mixing means, the toner containing means and the mixing means can be connected to each other at the shortest distance, and the toner can be efficiently used. It can be transported.

According to the present invention described in claim 7, the toner conveying means is made to operate when the toner concentration detecting device instructs the toner supply, whereby the electrophotographic device does not use extra electric power. be able to.

According to the present invention described in claim 8, by operating the toner conveying means in conjunction with the mixing means, a special driving means or a control circuit for operating the toner conveying means becomes unnecessary. Therefore, the electrophotographic device can be made inexpensive.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an arrangement state of a developing tank and a toner container around a photosensitive drum in an embodiment of an electrophotographic apparatus including a developing device according to the present invention.

FIG. 2 is a detailed sectional view of an example of a developing device in the electrophotographic apparatus according to the present invention.

FIG. 3 is a perspective view of an embodiment of a developing tank and a toner conveying path that constitute a developing device in the electrophotographic apparatus according to the present invention.

FIG. 4 is a perspective view of a toner transport path seen from a developing tank side that constitutes a developing device in the electrophotographic apparatus according to the present invention.

FIG. 5 is a perspective view of another embodiment of a developing tank and a toner conveying path that constitute a developing device in an electrophotographic apparatus according to the present invention.

FIG. 6 is a perspective view of a toner transport path seen from a developing tank side which constitutes another embodiment of the developing device in the electrophotographic apparatus according to the present invention.

FIG. 7 is a view for explaining the arrangement of toner storage means and a developing tank in the developing device in the conventional electrophotographic apparatus.

[Explanation of symbols]

1 photoconductor drum 5 Cyan (C) developing tank 9 Toner container 10 Toner transporting means 20 developing roller 21 mixing means 22 Toner density detection sensor 23 screw 24 Toner supply port 25 Toner flow 26 Bearing 27 Overflow means 28 Toner supply roller

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Claims (8)

[Claims] 1. A developing tank disposed around a photosensitive member carrying an electrophotographic latent image and having a developer mixing means, and a developing tank facing the photosensitive member of the developing tank for developing the latent image. A developing device in an electrophotographic apparatus having a developing roller arranged at a position and a toner storing means for supplying toner to the developing tank, wherein the developing tank is provided between the toner storing means and the developing tank. 2. A developing device in an electrophotographic apparatus, comprising: a toner conveying unit that supplies toner from a side opposite to the developing roller. 2. A developing tank corresponding to each color having a mixing device for a developer, which is arranged around a photoconductor carrying a latent image by an electrophotographic method, and a photoconductor of the developing tank for developing the latent image. In a developing device in an electrophotographic apparatus, which has a developing roller arranged at a position facing the body and a toner storing means for supplying toner to each of the developing tanks, at least one or more toner storing means, A developing device in an electrophotographic apparatus, which is provided between the developing tank and a developing tank corresponding to the developing tank, and which is provided with a toner conveying unit that supplies toner from a side of the developing tank facing the developing roller. 3. The developing device in an electrophotographic apparatus according to claim 1, wherein the toner conveying unit supplies the conveyed toner to an upper side of the toner in the developing tank. 4. The means for supplying the conveyed toner in the toner conveying means to the upper side of the toner in the developing tank is an overflow means provided between the toner conveying means and the mixing means. The developing device in the electrophotographic apparatus according to claim 3. 5. The developing device in an electrophotographic apparatus according to claim 1, wherein the toner storing means is provided above the toner conveying means. 6. The developing device in an electrophotographic apparatus according to claim 1, wherein the toner conveying unit is provided in a direction orthogonal to the mixing unit of the developing tank. 7. The developing device in an electrophotographic apparatus according to claim 1, wherein the toner conveying means operates when a toner concentration detecting device provided in the developing tank instructs the toner supply. 8. The developing device in an electrophotographic apparatus according to claim 1, wherein the toner conveying unit operates in conjunction with a mixing unit provided in the developing tank.