JPH0689061A - Developing device provided with automatic developer discharging means - Google Patents

Abstract

PURPOSE:To obtain a developing device provided with an automatic developer discharging means by which the stirring efficiency and the discharging efficiency of developer are enhanced. CONSTITUTION:The developing device for an image forming device is provided with a toner carrying unit 30 and a developing tank 20, and a magnetic roller 14 and a stirring roller 15 being rollers for developing are turnably and internally installed in the developing tank. A developer discharge port is formed on the bottom part of the developing tank, and a pair of 1st and 2nd screw-like rotating bodies arranged side by side for carrying the developer in an axial direction are installed in parallel with the roller for developing, and the 1st rotating body 27 is installed lower than the 2nd rotating body 28. The rotating body having a screw diameter larger than that of the 2nd rotating body 28 is used as the 1st rotating body 27. Then, it is possible that the rotating body having the screw diameter larger than that of the 1st rotating body 27 as the 2nd rotating body 28 on condition that the screw pitch of the 1st rotating body 27 is larger than that of the 2nd rotating body 28 is used in such a case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an electrophotographic image forming apparatus. In particular, it relates to a mechanism for discharging the developer in the developing tank.

[0002]

2. Description of the Related Art As a developing device of an image forming apparatus, there is a developing device as shown in FIG. 6 (Japanese Patent Application No. 4-10644).
7). FIG. 7 is a sectional view of FIG. In FIG. 6, 2 is a developing tank, 3 is a toner transport unit, the developing tank 2 is internally rotatably provided with a magnet roller 4 as a developing roller, and a stirring roller 5, and the developing tank 2 has a bottom portion. The developer discharge port 7 is formed, and as a discharging means for discharging the developer from the discharge port 7 to the outside of the developing tank 2, a pair of the first and second rotating bodies 1 arranged in parallel for conveying the developer in the axial direction.
7 and 18 are provided. Further, 6 is an agitator, 11 is a toner conveying screw, and 12 is a toner replenishing roller.

The first and second rotating bodies 17, 18 are provided in parallel with the developing rollers 4, 5. The developer is agitated by the developing rollers 4, 5 and the first and second rotating bodies 17, 18.

The rotating bodies 17, 18 are arranged such that the developer conveying directions are opposite to each other, and the rotating body 17 on one side faces the discharge port 7. And the rotating bodies 17, 1
A transport member 19 that transports the developer in the radial direction and circulates the developer is attached to one end of the transport direction side of 8. In order to reverse the conveying direction of the developer, the rotating bodies 17 and 18 are screw-shaped and arranged so that the twisting directions are the same, and the rotating directions of the rotating bodies 17 and 18 are opposite to each other. Alternatively, the twisting directions are arranged to be opposite to each other so that the rotating bodies 17 and 18 rotate in the same direction.

FIG. 8 shows a sectional view of the rotating body. The developer conveyed in the axial direction A by the first rotating body 17 is sent in the radial direction D by the conveying member 19 of the first rotating body 17 and reaches the second rotating body 18. This developer is conveyed by the second rotating body 18 in the axial direction in the direction B opposite to the previous direction, and is conveyed in the radial direction C by the conveying member 19 of the second rotating body 18.
In the axial direction, and again in the axial direction by the first rotating body 17. In this way, the developer is constantly circulated in the developing tank 2 and is also stirred vertically by the stirring roller 5.

When the life of the developer is reached, the developer is discharged and replaced. At this time, the outlet 7 is opened and the first and second rotating bodies 17, 18 are rotated. The developer is conveyed in the axial direction by the first rotating body 17 and reaches the discharge port 7,
The toner is discharged from the discharge port 7 to the outside of the developing tank 2 through the developer discharge pipe 13. Then, a new developer is supplied.

FIG. 9 is a schematic diagram showing a developer transport drive system in the developing tank 2 shown in FIG. The magnet roller 4, the stirring roller 5, and the agitator 6 are rotationally driven by a motor G arranged on the inner side of the main body of the image forming apparatus via a gear 4A, an idle gear G, a gear 5A, and a gear 6A.

[0008]

The rotating body used for stirring and discharging the developer disposed in the conventional developing tank is as follows.
Since both of them have the same shape and are provided in parallel with the developing roller, there are problems in stirring efficiency and discharge efficiency.

Therefore, it is an object of the present invention to provide a developing device for use in an image forming apparatus, which is equipped with an automatic developer discharging means for improving the stirring efficiency and discharging efficiency of the developer.

[0010]

According to the present invention, by improving the shape and arrangement of the rotating body used for stirring and discharging the developer in the developing tank of the conventional image forming apparatus as shown in FIG. , The above-mentioned purpose was achieved.

That is, first, two rotating bodies having mutually different screw diameters were adopted, and they were arranged so as to maintain the balance of the total amount of the developer conveyed. Secondly, two rotating bodies with different screw pitches were adopted. Third, we adopted a rotating body in which the diameter of the screw gradually increased toward one end. Fourthly, the rotating body is arranged on the discharge side in an inclined manner.

[0012]

[Function] Since the rotation amount of the screw is large, the developer conveyance amount is large. Therefore, by adopting two rotation units with different screw diameters, the conveyance amount of the whole developer can be kept balanced. can do. Also, the larger the screw pitch, the larger the amount of developer conveyed.Therefore, by adopting two rotating bodies with mutually different screw pitches, it is also necessary to keep the amount of developer conveyed in balance. You can By adopting a rotating body in which the diameter of the screw is gradually increased toward one end thereof, the amount of developer conveyed can be increased. By obliquely disposing the rotating body on the discharge side, the developer can be conveyed smoothly and in a short time.

[0013]

Embodiments will be described below with reference to the drawings.

Example 1 This example is an example in which two rotating bodies having different screw diameters are employed.

In the developing device of the image forming apparatus shown in FIG. 1, 20 is a developing tank, 30 is a toner conveying unit,
A magnet roller 14 as a developing roller and a stirring roller 15 are rotatably installed in the developing tank 20, and a developer discharge port is formed at the bottom of the developing tank 20. The developer is discharged from the discharge port to the developing tank. As a discharging means for discharging the developer to the outside of the unit 20, a pair of side-by-side screw-shaped first and second rotating bodies 27 and 28 that convey the developer in the axial direction are provided.
Further, 16 is an agitator, 21 is a toner conveying screw, and 22 is a toner replenishing roller.

The first and second rotating bodies 27 and 28 are provided in parallel with the developing rollers 14 and 15, and the first rotating body is provided below the second rotating body. Then, as the first rotating body, a screw whose diameter is larger than that of the screw of the second rotating body is used.

Regarding the cross-sectional view of the developing device, the cross-sectional view of the rotating body used in the developing device, and the developer transport drive system in the developing tank, basically, except for the shape of the rotating body used therein, This is similar to the conventional one shown in FIGS.

Example 2 In this Example, as shown in FIG. 2, contrary to FIG. 1, a screw whose diameter of the screw is larger than that of the screw of the first rotor is used as the second rotor. is there. However, in this case, it is necessary to change the screw pitch P shown in FIG. That is, the larger the screw pitch P is, the larger the carry amount is. Therefore, by making the screw pitch of the first rotating body larger than the screw pitch of the second rotating body, the balance of the entire carrying amount is maintained.

Example 3 In this example, as shown in FIG. 4, a rotating body in which the diameter of the screw is gradually increased toward one end thereof is adopted.

As described above, by adopting the rotating body in which the screw diameter is gradually increased, the amount of developer conveyed can be increased. Therefore, by using this rotating body, the amount of developer conveyed toward one end of the rotating body increases.

When this rotating body is used, instead of the first rotating body 17 in the developing tank shown in FIG. 6, the screw diameter is gradually increased toward one end of the rotating body as shown in FIG. The rotor is arranged so that the end with the larger diameter is on the front side.

Example 4 In this example, the rotary member 17 in the developing tank shown in FIG. 6 was used.
As shown in FIG. 5, 18 and 18 are examples in which they are inclinedly arranged on the discharge side at an angle of θ with respect to the horizontal.

With such an arrangement, when the developer is discharged, the developer can smoothly flow from A to E due to the influence of gravity and in a short time.

In the above, representative examples of the shape and arrangement of the rotating member arranged in the developing tank in order to improve the stirring efficiency and the discharging efficiency of the developer have been shown. It is obvious to those skilled in the art that various combinations of the rotating bodies shown in Example 3 can be set so as to maintain the balance of the amount of developer conveyed by the two rotating bodies.

[0025]

Since the developing device of the present invention is provided with the developer automatic discharging means as described above, it is possible to provide the developing tank in which the stirring efficiency and the discharging efficiency of the developer are improved.

That is, by adopting two rotating bodies having mutually different screw diameters, it is possible to keep the balance of the amount of conveyance of the entire developer. Further, by adopting two rotating bodies having different screw pitches, it is possible to maintain the balance of the transport amount of the entire developer. By adopting a rotating body in which the diameter of the screw is gradually increased toward one end thereof, the amount of developer conveyed can be increased. By arranging the rotating body on the discharge side in an inclined manner, the developer can smoothly flow from A to E due to the influence of gravity when the developer is discharged, and in a short time.

[Brief description of drawings]

FIG. 1 shows an example in which a developing device of the present invention uses, as a first rotating body, a screw whose diameter is larger than that of a screw of a second rotating body.

FIG. 2 shows an example in which, in the developing device of the present invention, a screw having a diameter larger than that of the screw of the first rotating body is used as the second rotating body.

FIG. 3 shows a rotating body used in the developing device of the present invention.

FIG. 4 shows a rotating body used in the developing device of the present invention in which the diameter of the screw is gradually increased toward one end of the rotating body.

FIG. 5 shows a rotating body in a developing tank of the developing device of the present invention,
An embodiment will be shown in which the device is tilted at an angle of θ with respect to the horizontal.

FIG. 6 shows a conventional image forming apparatus.

FIG. 7 is a sectional view of a developing device of the conventional image forming apparatus of FIG.

FIG. 8 is a sectional view of a rotating body used in a conventional developing device.

FIG. 9 is a schematic view of a developer transport drive system in a developing tank of a conventional developing device.

[Explanation of symbols]

 7 Developer Discharge Port 14 Magnet Roller 15 Stirring Roller 16 Agitator 20 Development Tank 17, 27 First Rotating Body 18, 28 Second Rotating Body 19 Conveying Member 30 Toner Conveying Device

Claims (4)

[Claims] 1. A toner transport unit and a developing tank, a developing roller having a magnet roller and a stirring roller rotatably mounted therein, and a developing tank having a developer discharge port at the bottom thereof. As a discharging means for discharging the developer from the discharge port to the outside of the developing tank, a pair of juxtaposed screw-shaped first and second rotating bodies that convey the developer in the axial direction are parallel to the developing roller, And in the developing device used in the image forming apparatus in which the first rotating body is provided below the second rotating body, the screw diameter of the screw is larger than the screw diameter of the second rotating body as the first rotating body. A developing device equipped with an automatic developer discharging means. 2. The second rotating body having a screw diameter larger than that of the first rotating body is used,
The developing device having the automatic developer discharging means according to claim 1, wherein the screw pitch of the first rotating body is larger than the screw pitch of the second rotating body. 3. As the first rotating body, a rotating body having a screw whose diameter is gradually increased toward one end of the rotating body is used so that the end having the larger diameter is located on the front side. A developing device comprising the automatic developer discharging device according to claim 1. 4. A pair of side-by-side screw-shaped first and second rotating bodies that convey the developer in the axial direction are used by being inclined on the discharge side at an angle of θ with respect to the horizontal. A developing device comprising the automatic developer discharging device according to claim 1.