JPH0882997A - Developing device - Google Patents

Abstract

PURPOSE: To provide a developing device solving the problem of torque-up or the like caused by the leakage of developer and attaching of fused developer. CONSTITUTION: As for the developing device which, at least, possesses a developing roller(developer carrier) 3, a supply roller(developer supplying member) 5, a developing container 1, at least, having an aperture part at one end, a bearing member 9 carried by the developing container 1 and carrying the developing roller 3 and the supply roller 5 to be rotatable, a supply roller shaft seal(first sealing member) 10 and a bush seal(second sealing member) having a shaft through-hole 11a, the supply roller shaft seal 10 is constituted of an elastic member having a lip part and the elastic member is arranged so as to face the root of the lip part on the side of the aperture part of the developing container 1 and to face the top end of the lip part outside. The lip part of the supply roller shaft seal 10 is inserted in the shaft part 5a of the supply roller 5 in the forward direction at the time of assembling, so that the curling of the lip part is prevented and the problem of the torque-up or the like due to the leakage of developer and the attaching of fused developer is solved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an image forming apparatus such as a copying machine or a printer which employs an electrophotographic system.

[0002]

2. Description of the Related Art Conventionally, in a developing device having a developing roller which is a developer carrying member and a supply roller which supplies toner which is a developer to the developing roller, leakage of toner from a shaft of the supply roller is prevented. 6 and 7
As shown in FIG. 3, a notch 101a for allowing the shaft portion 105a of the supply roller 105 to pass is formed in advance in the developing container 101, and after the supply roller 105 is installed in a predetermined position, an end seal of the developing roller 103 is formed. The bush 108 for forming the attachment surface of the developing container 106 is attached to the developing container 101.
And the tip of the supply roller 105 is rotatably supported by the developing container 101 via the bearing member 109 carrying the seal member 110 of the shaft 105a of the supply roller 105. .

Further, in order to prevent toner leakage between the developing container 101 (in particular, the bush 108) and the bearing member 109, the shaft portion 10 of the supply roller 105 is prevented.
The second seal member 1 is provided between both members in a form of penetrating 5a.
I was holding 11

By the way, since a toner used for forming a full-color image is generally required to have high fluidity and a low melting point, it is possible as a method of sealing a developing device using such toner, especially a shaft seal. In order to reduce the contact area with the shaft as much as possible (when the contact area is large, heat is generated, which causes toner fusion), and also to prevent the toner from entering the seal surface, the oil seal shown in FIG. It was particularly effective to use the seal member 110 having such a lip portion having elasticity.

[0005]

However, when using the seal member 110 having a lip portion as shown in FIG. 7, generally, the tip of the lip portion is directed toward the side to be sealed (the side with toner), It was common sense to direct the root to the opposite side, but the bearing member 109 is oriented in this way.
With the seal member 110 incorporated in the
When 10 is inserted into the shaft portion 105a of the supply roller 105, the tip of the lip of the seal member 110 is very likely to be curled, toner leakage occurs, and toner is fused to the bearing member 109, causing problems such as torque increase and locking. Was occurring frequently.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent curling of a lip portion of a seal member at the time of assembly to leak a developer and increase torque due to fusion of the developer. SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device which can solve the above problem and can always ensure a stable and high sealing property.

[0007]

In order to achieve the above object, the invention according to claim 1 has at least a developer carrier, and a roll-shaped developer supplying member for supplying the developer to the developer carrier. A developing container having an opening at least at one end, a bearing member that is carried by the developing container and rotatably carries the developer carrying member and the developer supplying member, and a bearing part of the developer supplying member of the bearing member. The first seal member, which is carried at the tip and fits with the shaft of the developer supply member to prevent the developer from leaking, and the first seal member and the bearing portion of the developer supply member of the developer container and the bearing member. And a second seal member having a through hole through which the shaft of the developer supply member penetrates in a substantially central portion thereof, wherein the first seal member is an elastic member having a lip portion. With configuring Sexual member, radically faces the opening side of the developer container of the lip portion, wherein the distal end of the lip portion is disposed so as to face outward.

According to a second aspect of the present invention, in the first aspect of the invention, the diameter of the tip of the lip portion of the first seal member is d ₂ , and the diameter of the shaft of the developer supply member is d ₁ . When this is done, it is characterized in that d ₁ / d ₂ = 1.05 to 1.2.

Further, in the invention according to claim 3, in the invention according to claim 1, the density of the second seal member is 55 k.
a foam member having elasticity of g / m ^{3 to} 120 kg / m ³ , and the diameter of the through hole of the second seal member is d ₃ .
When the diameter of the shaft of the developer supply member is d ₁ , it is set that d ₁ / d ₃ = 0.96 to 1.1.

[0010]

According to the present invention, the first seal member is made of an elastic member having a lip portion, and the elastic member is
Since the root of the lip portion faces the opening side of the developing container and the tip of the lip portion faces the outside, the lip portion of the first seal member serves as the shaft of the developer supply member during assembly. By inserting in the forward direction, curling of the lip portion is prevented, and problems such as developer leakage due to curling of the lip portion and torque increase due to fusion of the developer are solved. Even when the mounting direction of the seal member is reversed from the conventional one as in the present invention, high sealing performance is stably obtained.

[0011]

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

<Embodiment 1> FIG. 1 is a partial perspective view of a developing device according to Embodiment 1 of the present invention, FIG. 2 is a partial plan view of the developing device, FIG. 3 is a vertical sectional view of the developing device, and FIG. FIG. 3 is an enlarged sectional view of a shaft seal portion of the developing device.

As shown in FIG. 3, the developing device D according to this embodiment includes a developing container 1, a toner container 2, a developing roller 3 rotatably supported by the developing container 1, and the developing roller 3.
It comprises a developing blade 4 which comes into contact with the developing roller 4 to apply a thin layer of toner, and a supply roller 5 which supplies the toner to the developing roller 3, and as shown in FIG. End seals 6 are attached to both ends,
The end seal 6 is lightly pressed against the peripheral surface of the developing roller 3.

Further, as shown in FIG. 3, the developing roller 3
A blow-out prevention sheet 7 is carried between the downstream side of the rotation direction of the developing container 1 and the opening 1a of the developing container 1 along the longitudinal direction of the opening 1a, and its free end is in contact with the developing roller 3.

Further, as shown in FIG. 1, the developing container 1
A bush 8 is fitted in the bush 8, and the shaft portion 5a of the supply roller 5 is inserted into the bush 8.

As shown in FIG. 2, the developing roller 3 and the supply roller 5 are rotatably supported by shaft members 3a and 5a by bearing members 9, and the bearing members 9 have the bearing members 9 attached thereto. A supply roller shaft seal 10 for sealing between the shaft and the shaft portion 5a of the supply roller 5 is incorporated. Between the bush 8 and the bearing member 9, elasticity of urethane foam or the like fitted in the developing container 1 is provided. Bush seal 1
1 is sandwiched. The bush seal 11 has a density of 5
It is composed of a foamed member having elasticity of ^{5kg / m 3 ~120kg / m 3} . Further, the bush 8 has a shape such that when the bush 8 is fitted into the developing container 1, the bush 8 constitutes a pasting surface of the end seal 6.

As shown in FIG. 4, the supply roller shaft seal 10 has a lip portion 10a, and the shaft portion 5a of the supply roller 5 is fitted into the lip portion 10a so that the lip portion 10a is fitted. The portion 10a makes a line contact with the shaft portion 5a, which prevents toner from entering. Here, the supply roller shaft seal 10 has a lip portion 1 as shown in FIG.
0a is the outside of the bearing member 9 (the opening 1 of the developing container 1).
It is attached so as to face (a side opposite to a).

The shaft through hole 11a (see FIG. 1) provided in the bush seal 11 is for minimizing the amount of toner reaching the supply roller shaft seal 10 (that is, the supply roller shaft seal 10). In order to reduce the load), the diameter of the shaft portion 5a is set to be substantially the same as or slightly larger than that of the shaft portion 5a so that the shaft portion 5a is lightly fitted into the shaft through hole 11a.

In this embodiment, the diameter of the shaft portion 5a is φ5 mm and the diameter of the through hole 11a of the bush seal 11 is φ.
It has been set to the 4.6Mm～fai5mm, in general, the diameter of the shaft through hole 11a of the bush seal 11 d ₃
And the diameter of the shaft portion 5a of the supply roller 5 is d ₁ ,

[0020]

## EQU1 ## Good results are obtained by setting d ₁ / d ₃ = 0.96 to 1.1. Incidentally, the through hole 1
If the diameter of 1a is too small, toner fusion or coarse particles are likely to occur as described above, and problems such as increased torque and abnormal images are likely to occur.

Thus, in this embodiment, since the mounting direction of the supply roller shaft seal 10 is opposite to the conventional direction, the lip portion 10a of the supply roller shaft seal 10 is attached to the shaft portion 5a of the supply roller 5 during assembly. Since it is inserted in the forward direction, as a result, the lip portion 10a does not curl, and problems such as toner leakage and torque increase due to curling are solved. Even when the mounting direction of the supply roller shaft seal 10 is reversed from the conventional one as in the present embodiment, the toner sealing performance is not different from the conventional one.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view of the shaft seal portion of the developing device according to this embodiment. In this figure, the same elements as those shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be given below. Is omitted.

When a generally used (commercially available) oil seal is used as the shaft seal 10, the inner diameter of the lip portion of the oil seal is designed to prevent leakage by originally utilizing the pressure of the liquid. Since it is set, the fitting amount of the lip portion is set to a small value in order to seal the powder such as toner that hardly generates pressure.

Thus, the oil seal 1 used in this embodiment
The inner diameter of the lip portion 10a 'of 0'was 4.7 mm, but the recommended shaft diameter of this oil seal 10' was 5 mm, and the fitting amount of the oil seal 10 'was 0.3 mm (0. 15 mm).

However, in reality, satisfactory fitting cannot be realized due to, for example, the coaxiality between the bearing member 9 and the oil seal 10 ', and the dimensional tolerances of the inner diameter of the shaft portion 5a' and the oil seal lip portion 10a '. In some cases, toner leakage occurred.

Therefore, in the present embodiment, the above problem can be solved by setting the diameter of the shaft portion 5a 'of the supply roller to be φ5.3 mm.

Generally, when the diameter of the tip of the lip portion 10a 'of the oil seal 10' is d ₂ and the diameter of the shaft portion 5a 'of the supply roller is d ₁ ,

[0028]

## EQU2 ## Good results are obtained by setting d ₁ / d ₂ = 1.05 to 1.2.

The bush seal used at this time had a through hole diameter of φ4.9 mm to φ5.3 mm, which was particularly good.

[0030]

As is apparent from the above description, according to the present invention, the first seal member is composed of the elastic member having the lip portion, and the elastic member has the root of the lip portion as the developing container. The lip portion of the first seal member is inserted into the shaft of the developer supplying member in the forward direction at the time of assembly. It is possible to obtain an effect that the curling of the portion is prevented, and problems such as leakage of the developer due to curling of the lip portion and torque increase due to fusion of the developer are solved.

Further, even if the mounting direction of the seal member is reversed from the conventional one as in the present invention, high sealing performance can be stably obtained.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a developing device according to a first embodiment of the present invention.

FIG. 2 is a partial plan view of the developing device according to the first exemplary embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of the developing device according to the first exemplary embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a shaft seal portion of the developing device according to the first exemplary embodiment of the present invention.

FIG. 5 is an enlarged cross-sectional view of a shaft seal portion of a developing device according to a second exemplary embodiment of the present invention.

FIG. 6 is a partial perspective view of a conventional developing device.

FIG. 7 is a partial plan view of a conventional developing device.

[Explanation of symbols]

 D developing device 1 developing container 1a developing container opening 3 developing roller (developer carrier) 5 supply roller (developer supply member) 5a supply roller shaft (developer supply member shaft) 9 bearing member 10 supply roller shaft Seal (first seal member) 10a Lip portion 11 Bush seal (second seal member) 11a Shaft through hole (through hole)

Claims (3)

[Claims] 1. A developer carrying member, a roll-like developer supplying member for supplying a developer to the developer carrying member, a developing container having an opening at least at one end, and a developing container carried by the developing container. A bearing member that rotatably carries a developer carrier and a developer supply member, and a developer that is carried at the tip of the bearing portion of the developer supply member of the bearing member and is fitted to the shaft of the developer supply member. And a bearing portion of the developer supply member of the bearing member, and a shaft of the developer supply member penetrates the substantial center thereof. In a developing device including a second seal member having a through hole, the first seal member is composed of an elastic member having a lip portion, and the elastic member has the root of the lip portion of the developing container. Facing the opening side Developing apparatus is characterized in that the tip of the lip portion is disposed so as to face outward. 2. When the diameter of the tip of the lip portion of the first seal member is d ₂ and the diameter of the shaft of the developer supply member is d ₁ , d ₁ / d ₂ = 1.05 to 1.2 The developing device according to claim 1, wherein the developing device is set to. 3. The density of the second seal member is 55 kg /
When the diameter of the through hole of the second seal member is d ₃ and the diameter of the shaft of the developer supply member is d ₁ , the foam member has elasticity of m ^{3 to} 120 kg / m ³ , and d The developing device according to claim _{1, wherein 1} / d ₃ = 0.96 to 1.1 is set.