JPH08211737A - Developing device - Google Patents

Abstract

PURPOSE: To obtain a developing device capable of preventing the retaining of the flowing of toner and a developer in the vicinity of a sealing member, further, improving the sealability of the sealing member and prolonging a mechanical life. CONSTITUTION: At least a part or the whole of a bearing part facing the sealing member 17 disposed between a baring member 20 pivotally supporting the end part of the rotary shaft of the rotary member 4 in the developing device and the rotary member 4 is formed to a projected or trapezoidal shape, that is, projected to the side of the sealing member 17. Air vent holes for decreasing pressure 21 are formed in the vicinity of the bearing part facing the sealing member 17 and dustproof filters 22 are arranged in the air vent holes 21. A retainer 18 coming into contact with the sealing member 17 is coated with Teflon (R) and the sealing member 17 is made of a material for making the polarity of the triboelectric charge of the sealing member 17 the same as that of the charges of the toner and the developer.

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 image forming apparatus using a dry toner such as a copying machine, a printer and a facsimile.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus using a dry toner such as a copying machine, a printer and a facsimile, a rotary shaft of a rotating member such as a conveying paddle and a stirring roller disposed in a developing device. When the toner or the developer contained in the developing device enters the bearing portion of the bearing member that axially supports the end portion, toner is scattered through the bearing portion and the rotating torque of the rotating member increases ( If the torque of the drive source is increased, the load of the drive source becomes overloaded, and in the worst case, the rotation of the rotary shaft is blocked (roller lock), which causes problems.

As a technique for preventing the toner or the developer from entering a portion other than a predetermined portion, conventionally, the toner has been constituted so that the surface of the roll-shaped donor member and the back surface of the donor member have the same polarity. At least one of which does not move to the back surface of the donor member ("donor member" described in JP-A-60-182454), and sucks air toward the inside of the developing case by the air flow generated based on the developer conveying operation. By forming one hole in the side seal, it is possible to prevent the toner from scattering outside the developing device (JP-A-63-311).
The "developing device" described in Japanese Patent No. 284) has been proposed.

[0004]

By the way, in the conventional developing device, as shown in FIG. 5, the rotary shaft end portion of the rotating member (conveying paddle 4, stirring roller 5 and the like) arranged in the developing device. The V ring 17a and the G seal 1 are provided between the bearing member 20 that rotatably supports 4a and (5a) and the rotating member 4 and (5).
A seal member 17 such as 7b is provided to prevent the toner and the developer stored in the developing device from entering the bearing portion 20a of the bearing member 20.

However, in this conventional developing device,
As shown in FIG. 5 (a), the shape of the portion of the bearing member 20 in which the seal member 17 is arranged is formed in a concave shape, or, as shown in FIG. 5 (b), The facing surfaces of the developing device side plate 19 and the bearing member 20 that support the bearing member 20 with the seal member 17 (strictly speaking, the retainer 18 of the seal member 20) were formed flat (smooth).

Therefore, in the above-described conventional developing device, the toner and the developer are likely to stay near the seal member 17,
Due to the stagnation of the toner and the developer, the original sealability of the seal member 17 becomes incomplete, or the V ring 17a or G
For example, the lip of the seal 17b is damaged, and the seal member 1
There was a problem that the sealing property of No. 7 deteriorated with time. Such problems are caused by high-speed machines with high movability of the developing device,
This has been a particular problem in a long-life machine with a long maintenance cycle of the developing device.

The present invention has been made in view of the above points, and an object thereof is to prevent the flow of toner and developer in the vicinity of the seal member from being stagnated.
Another object of the present invention is to provide a developing device capable of improving the sealing property of the sealing member and the mechanical life thereof.

[0008]

In order to solve the above-mentioned problems, the present invention provides, in claim 1, a rotary shaft end portion of a rotary member disposed in a developing device of an image forming apparatus. A developing device in which a seal member for preventing the toner and the developer stored in the developing device from entering the bearing portion of the bearing member is disposed between the bearing member and the rotating member. In the above configuration, at least a part or the entire shape of the bearing portion facing the seal member is formed in a convex shape or a trapezoidal shape protruding toward the seal member side.

According to a second aspect of the present invention, a developing device of the image forming apparatus is provided in the developing device between a bearing member that axially supports a rotating shaft end portion of the rotating member and the rotating member. In a developing device provided with a seal member for preventing stored toner and developer from entering the bearing portion of the bearing member, a pressure reducing member is provided near the bearing portion facing the seal member. An air vent hole is formed.

According to a third aspect of the present invention, the air vent hole is
A dustproof filter is provided to prevent the toner and the developer from flowing out from the air vent hole.

Further, according to a fourth aspect of the present invention, between the rotating member and the bearing member that axially supports the rotary shaft end portion of the rotating member disposed in the developing device of the image forming apparatus, the developing device is provided inside the developing device. In a developing device provided with a seal member for preventing the stored toner or developer from entering the bearing portion of the bearing member, the contact surface of the member that comes into contact with the seal member is made of a low friction material. The structure is formed in.

Further, according to a fifth aspect of the present invention, between the rotating member and the bearing member that axially supports the rotary shaft end portion of the rotating member provided in the developing device of the image forming apparatus, the developing device is provided inside the developing device. In a developing device provided with a seal member for preventing stored toner and developer from entering the bearing portion of the bearing member, at least the contact surface of the seal member is made of the seal member. The triboelectric charge polarity is the same as that of the toner or the developer.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, the configuration and operation of a small-diameter two-stage sleeve developing device using a two-component developer embodying the present invention will be described with reference to FIG.

In FIG. 1, the developer in the developing device 1 is
It is supplied to the first sleeve 2 by the transport paddle 4. The developer supplied to the first sleeve 2 is formed into a thin layer with a constant thickness by the doctor 7, and the photosensitive drum 15
The electrostatic latent image formed on the photosensitive drum 15 is made visible by being conveyed to the surface of the photosensitive drum 15 by the first sleeve 2 and the second sleeve 3 which are rotationally driven in the forward direction. (develop. Here, the developer that does not contribute to the development is again transported into the developing device 1 by the transport paddle 4 and the stirring roller 5, and is stirred.

On the other hand, the excess developer whose delivery to the photosensitive drum 15 is restricted by the doctor 7 is sent to the separator 6 and the carrying screw 8 and laterally stirred. In addition, the developer after development is replenished with new toner sent by the agitator 9. The new toner is laterally agitated by the agitating roller 5, mixed with the agent, and supplied to the transport paddle 4 together with the excess developer returned by the separator 6.

Regarding the toner density of the developer in the developing device 1, the P sensor 16 detects the toner density of the image pattern for toner density detection formed on the photosensitive drum 15, and
A controller (not shown) makes a determination based on the detection result of the sensor 16. Here, when it is determined that the toner concentration in the developing device 1 is lower than the reference value, a toner supply motor (not shown) is driven, and new toner that has been previously replenished from the toner bottle 14 into the toner hopper 12 is generated.
The toner is replenished into the developing device 1 by the toner replenishing roller 11 via the toner transport paddle 13 and the second agitator 10. The toner replenishment operation is stopped when the toner concentration in the developing device 1 reaches the reference value due to the toner replenishment.

As shown in FIG. 2, at both ends (one end is not shown) of the rotary member (conveying paddle 4 here) in the developing device 1, a seal member 17 (one end is not shown) is provided at the rotary shaft end 4a. Here, a V ring 17a) is arranged, and this V ring 17a rotates together with the transport paddle 4. Further, a retainer 18 having excellent surface smoothness is arranged between the lip portion of the V ring 17a and the bearing member 20 to prevent toner and developer from entering the bearing portion 20a of the bearing member 20. It is set up.

By the way, as described above, in this type of conventional developing device, the shape of the portion of the bearing member 20 in which the seal member 17 is disposed is formed into a concave shape or the bearing member 20. Since the surfaces of the developing device side plate 19 and the bearing member 20 supporting the seal member 17 facing the seal member 17 (strictly speaking, the retainer 18 of the seal member 20) are formed flat (smooth), the toner is formed in the vicinity of the seal member 17. And the developer easily stagnate, and due to the stagnation of the toner and the developer, the original sealability of the seal member 17 becomes incomplete, and the lip portions of the V ring 17a and the G seal 17b are damaged. However, there was a problem that the sealing property of the above deteriorated over time.

Therefore, in the developing device according to the present invention, at least a part or the entire shape of the bearing portion facing the seal member 17 is formed into a convex shape or a trapezoidal shape protruding toward the seal member 17 side. That is, in the embodiment of the present invention shown in FIG. 2, the shape of the bearing portion (here, a part of the developing device side plate 19 and the bearing member 20) facing the seal member 17 (V ring 17a) is changed to the seal member 17 (V It is formed in a convex shape protruding toward the ring 17a). Further, in the embodiment shown in FIG. 3 of the present invention, the seal member 17 (V ring 1
7a) facing the bearing portion (here, the developing device side plate 19
And a part of the retainer 18) are formed in a trapezoidal shape protruding toward the seal member (V ring 17a) side.

According to these embodiments, the flow path of the toner and the developer contained in the developing device in the vicinity of the seal member 17 is the seal as shown by the arrow a in FIGS. 2 and 3. Since the bearing portion protruding toward the member 17 in a convex shape or a trapezoidal shape is formed so as to be away from the seal member 17, the toner and the developer are prevented from entering the bearing portion 20a, and the toner from the bearing portion 20a is prevented. Scattering, torque increase of the rotating member and roller lock are avoided.

Next, another embodiment of the present invention will be described. This embodiment is characterized in that a depressurizing air vent hole is formed in the vicinity of the bearing portion facing the seal member in the developing device. That is, in this embodiment, as shown in FIG. 4, the seal member 17 (V ring 17) in the developing device 1 is used.
a) In the vicinity of the bearing portion facing (a here, the bearing member 2)
The air vent hole 21 for decompression is formed in 0).

According to this embodiment, the internal pressure of the developing device 1 in the vicinity of the seal member 17 is reduced through the air vent hole 21, and the stagnation of the flow of toner and developer in the vicinity of the seal member is avoided. The toner scattering from the bearing portion 20a, the torque increase of the rotating member, and the roller lock are prevented.

Further, in this embodiment, the air vent hole 21
In order to prevent the toner and the developer from scattering through the developing device 1, a dustproof filter 22 is provided so as to close the air vent hole 21 as shown in FIG.

Next, still another embodiment of the present invention will be described. The present embodiment is characterized in that the contact surface of the member that comes into contact with the seal member 17 is made of a low friction material. That is, in this embodiment, for example, the V ring 17a
Teflon coating is applied to the contacted surface of the retainer 18 with which the lip portion of the retainer 18 contacts. According to this embodiment, the frictional resistance due to rotation between the seal member 17 (V-ring 17a) and the member (retainer 18) in contact with the seal member 17 is reduced, so that the durability of the seal member 17 is improved. Is improved, and the rotation torque of the rotating member and the generation of frictional heat are reduced. As a result, in this embodiment, the V ring 1
7a and the lip portion of the G seal 17b are prevented from being damaged, and the sealing performance of the seal member 17 is prevented from deteriorating with time.
The original sealability of the seal member 17 is maintained for a long period of time.

Next, still another embodiment of the present invention will be described. This embodiment is characterized in that at least the contacted surface of the seal member is made of a material whose triboelectrification polarity of the seal member is the same as that of the toner or the developer. That is, in this embodiment, for example, V
The materials of the ring 17a and the retainer 18 are selected according to the polarity of the toner used. More specifically, when the charging polarity of the toner is (−) polarity, the retainer 18 having a Teflon coating on the surface is used and the V ring 1 is used.
The material of 7a is fluororubber. According to this structure, the V ring 17a is triboelectrically charged to the (-) polarity when the rotating member rotates, and the polarity of the V ring 17a becomes the same as the polarity of the toner, so that the toner is electrostatically charged to the V ring 17a. Adsorption is prevented. Thus, according to this embodiment,
Since electrostatic attraction of toner and developer to the seal member is prevented, toner scattering from the bearing portion 20a, torque increase of the rotating member, and roller lock are prevented.

In each of the illustrated embodiments, the conveying paddle 4 is illustrated as the rotating member, but the present invention is applicable to all rotating members other than the conveying paddle (for example, the stirring roller 5).
Etc.) can be implemented. Further, in each of the illustrated embodiments, the V ring 17a is illustrated as the seal member, but the present invention can be applied to a seal member other than the V ring (for example, the G seal 17b).

[0027]

As described above, according to the present invention, in claim 1, the flow path of the toner or the developer accommodated in the developing device in the vicinity of the seal member is convex toward the seal member. Since the bearing part that protrudes in a trapezoidal shape or trapezoidal shape is formed away from the seal member, it is possible to prevent toner and developer from entering the bearing part, toner scattering from this bearing part, and torque increase of the rotating member. Also, the roller lock can be reliably avoided.

According to the present invention, the internal pressure of the developing device in the vicinity of the seal member can be reduced through the air vent hole, and the stagnation of the flow of toner and developer in the vicinity of the seal member can be avoided. It is possible to prevent scattering, torque increase of the rotating member, and roller lock.

According to the present invention, the internal pressure of the developing device in the vicinity of the seal member is reduced through the air vent hole, and the stagnation of the flow of toner and developer in the vicinity of the seal member can be avoided. It is possible to prevent scattering, torque increase of the rotating member, and roller locking, and it is possible to prevent toner and developer from the air vent hole from being scattered to the outside of the developing device by the dustproof filter arranged so as to close the air vent hole.

According to the present invention, the frictional resistance between the seal member and the member in contact with the seal member due to rotation can be reduced, the durability of the seal member can be improved, and the rotation torque and friction heat of the rotary member can be improved. Since it is possible to reduce the occurrence of, it is possible to prevent damage to the seal member (V-ring or lip portion of the G seal) and prevent deterioration of the sealability of the seal member with time.
The original sealability of the seal member can be secured for a long period of time.

According to the fifth aspect, electrostatic attraction of toner and developer to the seal member can be prevented, so that toner scattering from the bearing portion, torque increase of the rotating member, and roller lock can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a small-diameter two-stage sleeve type developing device using a two-component developer according to the present invention.

FIG. 2 is a schematic cross-sectional view of a bearing portion of a rotating member in the developing device according to the embodiment of the present invention.

FIG. 3 is a schematic sectional view of a bearing portion of a rotating member in a developing device showing another embodiment of the present invention.

FIG. 4 is a schematic sectional view of a bearing portion of a rotating member in a developing device showing still another embodiment of the present invention.

FIG. 5 is a schematic sectional view of a bearing portion of a rotating member in a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 1st sleeve 3 2nd sleeve 4 Conveying paddle (rotating member) 5 Stirring roller (rotating member) 6 Separator 7 Doctor 8 Conveying screw 9 1st agitator 10 2nd agitator 11 Toner supply roller 12 Toner hopper 13 Toner conveying paddle 14 toner bottle 15 photoconductor drum 16 P sensor 17 seal member 17a V ring 17b G seal 18 retainer 19 developing device side plate 20 bearing member 20a bearing portion 21 air vent hole 22 dust filter a

Claims (5)

[Claims] 1. A toner housed in a developing device of a developing device of an image forming apparatus, the toner being housed in the developing device between a rotating member and a bearing member that axially supports a rotary shaft end portion of the rotating member. In a developing device provided with a seal member for preventing a developer or a developer from entering the bearing portion of the bearing member, at least a part of or the entire shape of a bearing portion facing the seal member is formed into the seal member. A developing device having a convex shape or a trapezoidal shape protruding toward the member side. 2. A toner housed in the developing device between a rotating member and a bearing member that axially supports a rotary shaft end portion of a rotating member arranged in the developing device of the image forming apparatus. In a developing device provided with a seal member for preventing the developer and the developer from entering the bearing portion of the bearing member, a depressurizing air vent hole is formed near the bearing portion facing the seal member. A developing device characterized by the above. 3. The developing device according to claim 2, wherein the air vent hole is provided with a dustproof filter for preventing the toner and the developer from flowing out from the air vent hole. 4. A toner housed in the developing device between a rotating member and a bearing member that axially supports a rotary shaft end portion of a rotating member arranged in the developing device of the image forming apparatus. In a developing device provided with a seal member for preventing the developer and the developer from entering the bearing portion of the bearing member, the contact surface of the member that comes into contact with the seal member is made of a low friction material. Characteristic developing device. 5. A toner contained in the developing device between a rotating member and a bearing member that axially supports a rotary shaft end portion of a rotating member provided in the developing device of the image forming apparatus. In a developing device provided with a seal member for preventing the developer or the developer from entering the bearing portion of the bearing member, at least the contact surface of the seal member is made of a material whose frictional electrification polarity is A developing device, which is made of a material having the same charge polarity as the toner or the developer.