JP2003263030A - Developing roller and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the backlash of a magnet roller in the radial direction, to improve the relative dimension and the position reproducibility in assembling a developing doctor blade, and to improve the stability in terms of accuracy and the assembly efficiency after assemblage. <P>SOLUTION: The developing roller is provided with the magnet roller 1 which is arranged inside a developing sleeve 6 and equipped with a plurality of magnets in the circumferential direction, and the developing sleeve 6 is freely rotatably supported through a bearing between the magnet roller 1 and the developing sleeve 6. Tapered sliding bearings 4 and 5 are used as the bearings, and the roller is provided with a leaf spring 9 for energizing the bearings so as to remove the clearance in the radial direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roller provided in a developing device of an electrophotographic apparatus such as a copying machine, a printer and a facsimile, and an image forming apparatus provided with the developing roller, and more particularly to a two-component developing roller and its two-component developing roller. The present invention relates to an image forming apparatus including a developing roller.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a schematic configuration of an image forming apparatus. As shown in FIG. 5, an image forming apparatus such as a copying machine, a printer, and a facsimile uses a photoconductor drum 200 that forms a latent image and a developing device that develops the latent image formed on the photoconductor drum 200 in an electrophotographic process. And a device 100. The developing device 100 includes a developing roller 10
1 and a developing doctor blade 113 for regulating the developer layer thickness on the developing roller 101.

FIG. 6 is a view showing a positional relationship between a conventional developing roller and a developing doctor blade, and FIG. 7 is a side view of the same.
As shown in FIG. 6, the developing roller 101 includes a stationary magnet roller 102 and a rotating developing sleeve 10.
7 and 7. The structure of the magnet roller 102 includes a roll-shaped magnet main body having a plurality of magnets in the circumferential direction, and a fixed shaft 109 which is a fixed support shaft integrally formed with the magnet main body. The magnet roller 102 is arranged inside a developing sleeve 107 having a magnet body made of a non-magnetic cylindrical body. At both ends of the developing sleeve 107, a rotary shaft 108 serving as a rotary support shaft is provided.
Is integrally provided with a rear side flange 103 and a front side flange 105 having a through hole through which the fixed shaft 109 passes. And the rear side flange 10
3 is a slide bearing 104 that supports the fixed shaft 109 on the rear side.
The front side flange 105 is provided with a slide bearing 106 that supports a fixed shaft 109 on the front side. The front side flange 105 is provided with a seal 110 for preventing developer invasion.

In such a conventional developing roller 101, a rotary shaft 108 is rotatably supported by a support plate 111 via a bearing (not shown), and a fixed shaft 109 is fixed to the support plate 112. Further, a developing doctor blade 113 is attached to the support plates 111 and 112 via screws 116. The developing doctor blade 113 is arranged such that its tip and the surface of the developing sleeve 107 are separated by the doctor gap.

This developing roller 101 rotates the developing sleeve 107 to fix the magnet roller 102,
Two-component developer with carrier and toner
And the latent image on the photosensitive drum 200 can be developed.

[0006]

However, when setting the gap between the magnet roller 102 and the developing doctor blade 113, the set value of the doctor gap is not stable due to the backlash of the magnet roller 102. Particularly, due to the structure of the magnet roller 102, as shown in FIG.
There is a large play between the slide bearing 106 and the slide bearing 106. The reason is that the rotary shaft 108 on the rear side, the flange 103, and the developing sleeve 107 have an integral structure, but the fixed shaft 109 on the front side has an integral structure with the magnet body, and the developing sleeve side and the magnet roller side are independent. Cage, bearing 1
This is because most of them are supported by the part 06. That is, the backlash G in this portion directly affects the accuracy in the radial direction.

As shown in FIG. 6, when the rotating shaft 108 and the fixed shaft 109 are used as a reference, there is a play G of the developing sleeve 107.
However, when the developing doctor blade 113 is assembled and adjusted, a change in accuracy occurs. Here, the rear doctor gap 114 and the front doctor gap 11
5 clearly shows the difference in the amount of play and play.

The magnet roller 1 is used for adjustment.
02 and the developing doctor blade 113 are inserted with a clearance gauge, and the developing doctor blade 113 is assembled while being pressed, but at this time, the amount of bearing play inside the developing roller 102 is picked up due to variations and the set amount. The doctor gap cannot be obtained even if the gap gauge is inserted.

Further, after the magnet roller 102 is installed in the developing unit, the amount of backlash causes a doctor gap variation and adversely affects the developing characteristics such as the density. Further, there is a problem that the number of assembly adjustments is increased due to instability of the deflection accuracy.

Therefore, the present invention reduces the amount of play in the radial direction of the magnet roller, improves the relative size and position reproducibility of the developing doctor blade when assembling, and stabilizes the accuracy after assembling and improves the assembling property. It is an object of the present invention to provide a developing roller and an image forming apparatus that can be improved.

[0011]

In order to achieve the above-mentioned object, the invention of claim 1 is provided with a magnet roller which is arranged inside a developing sleeve and in which a plurality of magnets are arranged in the circumferential direction. A developing roller in which the developing sleeve is rotatably supported via a bearing between the developing sleeve and a biasing means for biasing the bearing so as to remove a radial clearance of the bearing. It is characterized by being.

According to a second aspect of the present invention, the bearing is an inclined slide bearing, and the urging means includes an elastic member for urging the half body of the inclined slide bearing in the thrust direction. The developing roller according to claim 1, wherein the developing roller is a developing roller.

According to a third aspect of the present invention, the bearing is an inclined ball bearing, and the urging means includes an elastic member for urging the half body of the inclined ball bearing in the thrust direction. The developing roller according to claim 1, wherein the developing roller is a developing roller.

According to a fourth aspect of the present invention, of the pair of bearing halves constituting the bearing, one is attached to the magnet roller side and the other is attached to the developing sleeve side. 4. The developing roller according to claim 2, wherein the developing roller is movable to the right and the movable bearing half is urged by the elastic member.

A fifth aspect of the present invention is an image forming apparatus including the developing roller according to any one of the first to fourth aspects.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a developing roller of a first embodiment which is an embodiment of the present invention.

As shown in FIG. 1, the developing roller comprises a stationary magnet roller 1 and a rotating developing sleeve 6.
It has and. The structure of the magnet roller 1 includes a roll-shaped magnet main body having a plurality of magnets in the circumferential direction, and a fixed shaft 8 which is a fixed support shaft integrally formed with the magnet main body. The magnet roller 1 is arranged inside a developing sleeve 6 having a magnet body made of a non-magnetic cylindrical body. At both ends of the developing sleeve 6, a rear side flange 2 integrally provided with a rotary shaft 7 as a rotary support shaft and a front side flange 10 having a through hole through which a fixed shaft 8 penetrates are integrally provided. The rear side flange 2 has a taper portion 8b serving as a rear side fixed shaft.
The tapered slide bearing 3 for supporting the shaft is provided, and the front side flange 10 is provided with the tapered slide bearing 4 for supporting the fixed shaft 8 on the front side. A seal 110 for preventing developer invasion is provided on the front side flange 10 as in the conventional example.

The tapered slide bearing 3 attached to the rear side flange 2 bears a tapered portion 8b coaxial with the fixed shaft 8 of the magnet roller 1 by means of mutually tapered surfaces.

Further, the tapered slide bearing 4 attached to the tapered slide bearing 3 is rotatably supported by a tapered slide bearing 5 having a tapered surface that follows the tapered surface. The tapered slide bearing 5 is provided with a key 5a that forms a key groove together with an axial groove 8a formed in the fixed shaft 8 of the magnet roller 1. As a result, the tapered plain bearing 5 is movable only in the axial direction of the fixed shaft 8. A leaf spring 9 which is an elastic member provided in the biasing means is arranged between the tapered plain bearing 5 and the end surface of the magnet roller 1. This leaf spring 9 presses and urges the tapered slide bearing 5 in the thrust direction, whereby the tapered slide bearing 3 of the rear side flange 2 and the taper portion 8b of the magnet roller 1 are brought into pressure contact with each other, and the tapered slide bearing is also formed. 5 and the tapered slide bearing 4 are pressed against each other. Therefore, the radial clearance between the bearings is minimized.

As described above, in the present invention, as a measure for removing the radial play, which has been a problem in the related art, a method of removing the radial play by applying a force in the thrust direction to form a gap is adopted. Specifically, the taper slide bearing 3 is a taper slide bearing, and when the taper portion 8b as the fixed shaft of the magnet roller 1 is inserted, the taper positioning can be performed on the rear side. Further, on the front side flange 10 side, a tapered slide bearing 4 and a tapered slide bearing 5 are provided.
Is attached, and the leaf spring 9 has a tension function in the thrust direction. With this tension function and the tapered plain bearings 4 and 5, the radial direction play can be removed by the thrust direction force. Similarly, the tapered slide bearing 3 and the tapered portion 8b can remove play in the radial direction.

2A and 2B are views showing the biasing means. FIG. 2A is a front view of the leaf spring of the first example which is the biasing means, FIG. 2B is the same plan view, and FIG. 2C is the biasing means. The front view of the leaf spring of a certain 2nd example, (D) is the same top view.

Here, as shown in FIGS. 2 (A) and 2 (B), the leaf spring is a flat spring steel material having a spring property, and has a spring claw 9a on the spring base 9 in a rising shape.
The claw tip 9b serves to prevent the thrust force and the tapered slide bearing 5 from rotating. The direction of the spring claw 9a is opposite to the rotation direction. Therefore, when this leaf spring is used, the tapered slide bearing 5 and the fixed shaft 8 can be prevented from rotating, so that the key 5a and the groove 8a may be omitted. Further, when the key 5a and the groove 8a are provided, rubber, spring or the like can be used as the elastic member.

The spring claws 9a can be provided in a plurality of rows, and the spring claws 9a can face each other to form a detent structure in the forward and reverse directions. In addition, as shown in FIGS. 2 (A) and (B) and FIGS. 2 (C) and (D), individual shapes are provided. 2C and 2D, the spring claw 19 is provided on the outer peripheral side of the spring base 19.
a and the claw tip portion 19b are arranged.

When the leaf spring shown in FIG. 2 is used as the biasing means, the key grooves (key 5a, groove 8a) can be omitted. Further, when the key groove is provided, as the elastic member provided in the biasing means, other elastic bodies such as rubber and spring can be used in addition to the leaf spring.

FIG. 3 is a view showing a developing roller of a second embodiment which is an embodiment of the present invention. As shown in FIG.
This developing roller includes tapered slide bearings 11a, 1a at both ends of the outer peripheral surface of the magnet body of the magnet roller 11.
1b is provided, and tapered bearings 11a and 11b are adhered to the outer shapes of both ends of the magnet body. Further, bearings 16 and 17 are mounted on the inner surfaces of both ends of the developing sleeve 15 to provide a bearing function. In this embodiment, an axial key 15a, which is a protrusion along the axial direction, is provided on the inner circumference of the developing sleeve 15, and an axial groove 17a is provided on the outer circumference of the tapered slide bearing 17, and the key 15a is provided.
And the groove 17a form a key groove. However, when the leaf spring of FIG. 2 is used as the biasing means, the key groove can be omitted as in FIG. Further, when the key groove is provided, another elastic body can be used as the biasing means as in the embodiment of FIG. Reference numeral 20 indicates a fixed shaft.

Here, the assembly is such that the tapered sleeve bearings 16 and 17 are attached to the developing sleeve 15, the rear side flange 13 having the rotating shaft 18 is fixed, the magnet main body is inserted, the bearing 17 is inserted from the right side, and then the leaf spring 19 is inserted. Insert and fix the front flange 14. With these configurations, due to the taper structure at both ends of the magnet body, the force in the thrust direction is received from the leaf spring 19, and the play can be removed by absorbing the gap in the radial direction.

FIG. 4 is a view showing a developing roller of a third embodiment which is an embodiment of the present invention. As shown in FIG.
In this developing roller, the angular ball bearing 23 is used as a bearing.
Was used. That is, the outer race 23a of the angular ball bearing 23 is attached to the front side flange 22, and the inner race 23b is provided with an axial key 23c on the inner peripheral surface thereof and an axial groove 24a formed in the fixed shaft 24 of the magnet roller 21. And it was attached so that it could slide in the axial direction. It should be noted that the key 23c and the groove 24a can be omitted in the same manner as the embodiment shown in FIG. 1 when the leaf spring of FIG. 2 is used.

That is, in the embodiment of FIG. 1, the angular contact ball bearing 23 is used in place of the tapered slide bearings 4 and 5, and the other structure is the same as that of the embodiment of FIG. When this angular contact ball bearing 23 is used, the cost is slightly increased, but the accuracy can be easily secured. The reference numeral 24 indicates a fixed shaft.

As described above, the present invention has a problem in that the relative position and the size of the magnet roller with respect to the developing sleeve which is a counterpart component of the magnet roller are changed due to the backlash on one side of the length of the magnet roller.

As a solution to this problem, a taper bearing system is adopted for the bearing, and a force is applied in the thrust direction so that the amount of movement corresponding to the gap acts in the radial direction of the bearing to remove play.

According to the developing roller of the above-described embodiment, by providing the mechanism for removing the play of the bearing portion between the fixed side magnet roller and the rotating side developing sleeve, the left and right backlash of the developing sleeve surface of the developing roller. , The deflection deviation has disappeared,
The size and variation with the doctor gap can be set small. In addition, it is possible to stabilize the developing characteristics after incorporating the developing unit. Further, by improving the accuracy of parts, the assembly adjustment time can be shortened and the malfunction of the unit can be reduced to save energy. The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the gist of the present invention.

[0032]

As described above, according to the developing roller of the present invention, the amount of play in the radial direction of the magnet roller is reduced, and the relative size and position reproducibility of the developing doctor blade during assembly are improved. It is possible to improve the stability of the doctor gap accuracy after assembly and the assemblability.

Further, according to the image forming apparatus of the present invention, it is possible to prevent the development unevenness due to the doctor gap variation, so that the image quality can be greatly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a developing roller of a first embodiment which is an embodiment of the present invention.

2A and 2B are views showing a biasing means, FIG. 2A is a front view of a leaf spring of a first example which is a biasing means, and FIG.
(C) is a front view of a leaf spring of a second example which is a biasing means,
(D) is a plan view of the same.

FIG. 3 is a diagram showing a developing roller according to a second embodiment which is an embodiment of the present invention.

FIG. 4 is a diagram showing a developing roller according to a third embodiment, which is an embodiment of the present invention.

FIG. 5 is a diagram showing a schematic configuration of an image forming apparatus.

FIG. 6 is a view showing a conventional developing roller.

FIG. 7 is a side view of a conventional developing roller.

[Explanation of symbols]

1 magnet roller 2 Rear side flange 3,4,5 Tapered plain bearings 6 Development sleeve 7 rotation axis 8 fixed axis 8b taper part 9 Spring base (leaf spring) 10,14 Front flange 11 Magnet roller 11a tapered plain bearing 11b tapered plain bearing 13 Rear flange 15 Development sleeve 16,17 tapered plain bearing 18 rotation axis 19 Spring base (leaf spring) 20 fixed axis 21 Magnet roller 22 Front flange 23 Angular Contact Ball Bearing 24 fixed axis G backlash

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/00 550 G03G 15/00 550 15/08 501 501/08 501Z F term (reference) 2H031 AC08 AC13 AC18 AC19 2H071 BA03 BA16 BA19 BA36 BA43 DA08 2H077 AD02 AD06 BA03 FA16 FA21 3J012 AB02 AB03 BB01 BB03 CB03 DB09 FB01 FB10 GB10 HB01 3J103 AA02 AA13 AA23 AA25 DA01 DA05 DA07 FA15 FA18 GA02 GA57 GA58 GA60

Claims (5)

[Claims] 1. A developing device comprising a magnet roller arranged inside a developing sleeve and having a plurality of magnets arranged in a circumferential direction, wherein the developing sleeve is rotatable via a bearing between the magnet roller and the developing sleeve. The developing roller being supported is provided with an urging means for urging the bearing so as to remove a radial clearance of the bearing. 2. A bearing according to claim 1, wherein the bearing is an inclined slide bearing, and the urging means includes an elastic member for urging the half body of the inclined slide bearing in a thrust direction. The developing roller described. 3. The bearing according to claim 1, wherein the bearing is an inclined ball bearing, and the urging means includes an elastic member for urging the half body of the inclined ball bearing in a thrust direction. The developing roller described. 4. A pair of bearing halves constituting the bearing, one of which is attached to the magnet roller side and the other of which is attached to the developing sleeve side, and one of the bearing halves is axially movable, and the movable half is movable. The developing roller according to claim 2 or 3, wherein a simple bearing half is urged by the elastic member. 5. An image forming apparatus comprising the developing roller according to claim 1.