JPH0820802B2 - Development device - Google Patents

Description

The present invention relates to a developer leakage prevention mechanism in a developing device in an electrophotographic image forming apparatus.

<Prior Art> Generally, as shown in FIG. 3, a developing device in an image forming apparatus includes a developing tank 1 containing a developer composed of toner and a carrier and a developing roller 3 for conveying the developer to a photoconductor 2. Agitating rollers 4 and 5 for agitating the developer, an agitator 7 for crushing the toner replenished from the toner replenishing port 6,
A developer carrying magnetic roller 8 is rotatably provided. In the figure, 9 and 10 are sink plates, and 11 is a doctor.

As shown in FIG. 4, the stirring rollers 4 and 5 are rotatably supported on the tank wall 1a of the developing tank 1 through a bearing 13 made of a sintered material, and the rotating shaft 12 and the bearing are supported. A V-shaped sealing material 14 for sealing between the rollers 13 and 13 is attached to the end surfaces of the rollers 4 and 5.

Further, a pulley 15 is attached to one end of the rotary shaft 12, a belt 16 for driving the rotary shaft 12 is wound around the pulley 15, and the belt 16 is connected to a driving device (not shown).

<Problems to be Solved by the Invention> In the above-described conventional technique, when a radial load P is applied to the pulley 15 due to vibration of the drive device, the rotary shaft 12 is eccentric, and the rotary shaft 12 and the bearing 13 are worn. , Sealing material 14
The contact with the bearing 13 fluctuates and abnormal wear of the sealing material 14 occurs. Therefore, sealing between the rotary shaft 12 and the bearing 13 cannot be sufficiently performed, and there is a problem that the developer leaks from between the rotary shaft 12 and the bearing 13.

In view of the above, it is an object of the present invention to provide a developing device that can prevent wear of a bearing due to eccentricity due to a load being applied to a rotating shaft and can improve the sealing property of a developer to a developing tank. .

<Means for Solving the Problems> In the means for solving the problems according to the present invention, as shown in FIGS. 1 and 2, the developing tank 1 rotatably supports the rotating shafts 12 of the rollers 4 and 5 for conveying the developer. A bearing 20, a bearing holder 21 for fitting and holding the bearing 20, and a coupling means 22 for movably coupling the bearing holder 21 to the tank wall 1a of the developing tank 1 in the radial direction of the rotating shaft 12. A first sealing material 23 that seals between the rotary shaft 12 and the bearing 20, and a second sealing material 24 that seals between the bearing holder 21 and the tank wall 1a of the developing tank 1. Is provided, and the second sealing material 24
Is slidably in contact with the surface of the bearing holder 21 or the tank wall 1a of the developing tank 1 parallel to the radial direction of the rotary shaft 12.

<Operation> In the above problem solving means, in order to convey the developer in the developing tank 1 while stirring, the rotating shaft 12 is rotated to operate the stirring rollers 4 and 5.

At this time, when the rotary shaft 12 receives a radial load due to vibration of the drive motor or the like, or when the developer in the developing tank 1 exerts a load on the stirring rollers 4 and 5, the rotary shaft 12 fixes the bearing 20. However, since the bearing holder 21 that holds the bearing 20 is movable in the radial direction of the rotating shaft 12, the bearing holder 21, the bearing 20, and the rotating shaft 12 are integrated. And the rotary shaft 12 is not eccentric. Therefore, wear between the rotating shaft 12 and the bearing 20 is reduced, and abnormal heat generation is suppressed. At this time, the rotation axis
With respect to the first sealing material 23 that seals between 12 and the bearing 20, the bearing 20 always moves in parallel while being in contact, so abnormal wear of the first sealing material 23 can also be prevented and rotation can be prevented. Leakage of the developer from between the shaft 12 and the bearing 20 is prevented.

Further, although the bearing holder 21 slides with respect to the tank wall 1a,
The second sealing member 24 blocks the sliding contact surface between the bearing holder 21 and the tank wall 1a from the inside of the developing tank 1, and prevents the developer from leaking between the bearing holder 21 and the tank wall 1a. It

Therefore, even if there is a radial load on the rotary shaft 12,
The bearing holder 21 that fits and holds the bearing 20 is a tank wall 1a of the developing tank 1.
Since it is movably supported in the radial direction of the rotary shaft 12, it is difficult for an excessive load to be applied to the bearing 20, and wear of the rotary shaft 12, the parts such as the bearing 20 is reduced. Furthermore, the sealing property of the developer is improved by the first sealing material 23 and the second sealing material 24. Therefore, it is possible to prevent the developer from leaking from the developing tank 1.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a bearing portion of a roller showing an embodiment of the present invention, FIG. 2 is a sectional view of a sealing material, and FIG. 3 is a configuration diagram of a developing device.

In the developing device of this embodiment, as shown in FIG. 3 shown in the prior art, the developing roller 3, the stirring roller 4, and the developing roller 3 are provided inside the developing tank 1.
5, an agitator 7, and a carrying magnetic roller 8 are rotatably provided.

Then, in the developing tank 1, the rotation shaft 12 of the stirring rollers 4 and 5 is
A bearing 20 for rotatably supporting the bearing 20, a bearing holder 21 for holding the bearing 20, and the bearing holder 21 coupled to the tank wall 1a of the developing tank 1 in a free state in the radial direction of the rotary shaft 12. A coupling means 22, a first sealing material 23 that seals between the rotary shaft 12 and the bearing 20, and a second seal that seals between the bearing holder 21 and the tank wall 1a of the developing tank 1. A stopper 24 is provided.

The bearing 20 is formed of a sintered material in a cylindrical shape having a circular hole 20a at the center, the rotary shaft 12 is inserted into the circular hole 20a, and a flange 20b is provided at the outer end of the developing tank 1. Has been formed.

The bearing holder 21 has a cylindrical portion 2 having a stepped hole 25a in the center.
5 and a flange-shaped coupling portion 26 formed on the outer periphery of the tubular portion 25. Then, the bearing 2
0 is fitted, and the inner and outer end surfaces of the bearing holder 21 and the bearing 20 are flush with each other.

The opening through which the rotary shaft 12 is inserted in the tank wall 1a of the developing tank 1.
27 is formed, and the opening 27 is sufficiently spaced from the rotary shaft 12 so as not to come into contact with the rotary shaft 12 due to eccentricity. A convex portion 28 is formed on the outer edge of the opening 27 so as to face the outside of the developing tank 1.

As the connecting means 22, a plurality of stepped screws 29 are used for connecting the connecting portion 26 of the bearing holder 21 to the convex portion 28 of the tank wall 1a, and the stepped screw 29 has a screw portion 29a on the tip side. And a step portion 29b having a diameter larger than that of the screw portion 29a.

Then, the screw hole 28a is provided in the convex portion 28 of the tank wall 1a, and the screw portion 29a of the stepped screw 29 is screwed into the screw hole 28a, so that the bearing holder 21 is moved in the axial direction of the rotating shaft 12 (first It is fixed in the x direction in Fig. 1 (actually, it moves about 0.1 mm). Further, a through hole 26a having a diameter larger than that of the stepped portion 29b of the stepped screw 29 is bored in the coupling portion 26 of the bearing holder 21, and the stepped screw 29 is inserted into the through hole 26a. There is a gap between 26a and the step 29b of the stepped screw 29 that can be displaced by about 1 mm in the radial direction of the rotary shaft 12 (y direction in FIG. 1, z direction (perpendicular to the paper surface)). Bearing holder for the outer surface of the convex portion 28 of 1a
The inner surface of 21 is slidable.

As shown in FIG. 2, the first sealing material 23 and the second sealing material 24 are made of rubber, and have an annular main body portion 30, an annular sliding contact portion 31 having an octagonal cross section, and a main body portion. It is composed of a hinge portion 32 connecting the sliding contact portion 31 to the sliding portion 30.

Then, the first sealing material 23 has a rotating shaft on the main body portion 30.
12 is inserted and adhered to the stirring rollers 4 and 5, and the sliding contact part 3
1 is in sliding contact with the inner surface of the bearing 20.

The second sealing material 24 is bonded by inserting the tubular portion 25 of the bearing holder 21 into the main body portion 30, and the sliding contact portion 31 is provided between the opening 27 and the convex portion 28 of the tank wall 1a. It touches the outer surface.

Further, a pulley 33 is attached to the outside of the bearing 20 of the rotary shaft 12, and a belt 34 that transmits the drive from a drive motor (not shown) is wound around the pulley 33. And the axis of rotation
The end of 12 is rotatably supported via a ball bearing 37 on a reinforcing plate 36 fixed to the tank wall 1a of the developing tank 1 with screws 35.

In the above structure, in order to convey the developer in the developing tank 1 while stirring, the driving motor is driven to rotate the rotating shaft 12 by the belt 34 to operate the stirring rollers 4 and 5.

At this time, when the rotary shaft 12 receives a radial load due to vibration of the drive motor or the like, or when the developer in the developing tank 1 exerts a load on the stirring rollers 4 and 5, the rotary shaft 12 fixes the bearing 20. The bearing holder 21 for holding the bearing 20 is a stepped screw of the coupling means 22 even though the bearing holder 21 holds the bearing 20.
The rotation shaft 12 is not eccentric because it can be freely moved in the radial direction of the rotation shaft 12 by 29 and the through hole 26a of the coupling portion 26. Therefore, wear between the rotating shaft 12 and the bearing 20 is reduced, and abnormal heat generation is suppressed. Then, since the bearing 20 always moves in parallel with the sliding contact portion 31 of the first sealing material 23 that seals between the rotary shaft 12 and the bearing 20, the first sealing material 23 Abnormal wear can also be prevented, and leakage of the developer between the rotary shaft 12 and the bearing 20 can be prevented.

Further, the coupling portion 26 of the bearing holder 21 slides with respect to the convex portion 28 of the tank wall 1a, but the sliding contact surface between the bearing holder 21 and the tank wall 1a is made by the second sealing material 24. The interior of the bearing is blocked, and the developer is prevented from leaking between the bearing holder 21 and the tank wall 1a.

Therefore, even if there is a radial load on the rotary shaft 12,
Since the bearing 20 is supported in a free state with respect to the tank wall 1a of the developing tank 1, it is difficult for an excessive load to be applied to the bearing 20,
Wear of parts such as the rotating shaft 12 or the bearing 20 is reduced. Furthermore, the sealing property of the developer is improved by the first sealing material 23 and the second sealing material 24. Therefore, it is possible to prevent the developer from leaking from the developing tank 1.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, although the present embodiment is performed on the stirring rollers 4 and 5, it may be performed on the developing roller.

<Effects of the Invention> As is apparent from the above description, according to the present invention, the bearing holder for fitting and holding the bearing of the rotating shaft is supported by the tank wall of the developing tank so as to be movable in the radial direction of the rotating shaft. Therefore, when a radial load is applied to the rotary shaft, the bearing holder, the bearing and the rotary shaft move in the radial direction, and the rotary shaft is not eccentric.

For this reason, it becomes difficult for an excessive load to be applied to the bearing, and wear of parts such as the rotating shaft and the bearing can be reduced.

Moreover, the first sealing material can prevent the developer from leaking from between the rotary shaft and the bearing, and the second sealing material can prevent the developer from developing between the bearing holder and the tank wall. It is possible to prevent the agent from leaking.

Also, since the second sealing material is in sliding contact with the surface of the bearing holder or the tank wall of the developing tank that is parallel to the radial direction of the rotating shaft, the bearing holder moves in the radial direction of the rotating shaft. Even in such a case, there is an excellent effect that the second sealing material can be surely sealed without applying an unreasonable force to the second sealing material or forming a gap in the sealing portion.

[Brief description of drawings]

FIG. 1 is a sectional view of a bearing portion of a roller showing an embodiment of the present invention, FIG. 2 is a sectional view of a sealing material, FIG. 3 is a configuration diagram of a developing device, and FIG. 4 is a conventional roller bearing. It is sectional drawing of a part. 1: development tank, 4,5: stirring roller, 12: rotating shaft, 20: bearing, 21:
Bearing holder, 22: coupling means, 23: first sealing material, 24: second sealing material.

Claims (1)

[Claims] 1. A bearing for rotatably supporting a rotary shaft of a roller for transporting a developer in a developing tank, a bearing holder for fitting and holding the bearing, and a bearing holder for a wall of the developing tank. A coupling means for movably coupling to the radial direction of the rotation axis,
A first sealing material that seals between the rotating shaft and the bearing, and a second sealing material that seals between the bearing holder and the tank wall of the developing tank are provided, and the second sealing material is provided. The developing device is characterized in that the stopper is slidably in contact with either the bearing holder or the tank wall of the developing tank on a surface parallel to the radial direction of the rotating shaft.