JPH10301395A - Magnet roll for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve parts accuracy and assemblability by adopting two of shaft member respectively in the same shape being shorter than a magnet roll, and making respective flange on a sleeve both end as common parts. SOLUTION: In this magnet roll 12 for developing, since the shaft 34 supported rotatably by the shaft hole in the flange 30 is fixed with one end section of the magnet roll 18, and the shaft 36 fixed in the shaft hole of the flange 32 is supported rotatably by the other end of the magnet roll 18, the magnetic roll 18 by the shaft 34, and the sleeve 20 by the shaft 36 respectively is made possible to be independently rotatively driven. Moreover, the need of the shaft member penetrating the magnet roll 18 is eliminated by adopting two shafts 34 and 36 in the same shape, and respective length of shafts 34 and 36 can be composed shorter than the conventional shaft member, therefore the parts accuracy can be raised. Moreover, the number of component can be reduced by respective making two of flanges 30 and 32, and the shafts 34 and 36 in the same shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet roll used in an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus such as a copying machine, a developing device for developing an electrostatic latent image formed on a photoreceptor with toner is provided with a developing magnet roll. I have. The developing magnet roll includes a cylindrical sleeve that is rotatably held, and a magnet roll that is disposed in the sleeve and has a plurality of magnetic poles in a circumferential direction. Then, the developer containing the toner supplied to the developing magnet roll in the developing device is conveyed to the developing area according to the rotation of the sleeve while being held on the sleeve by the magnetic force of the magnet roll, where the developer contacts the photosensitive member. The electrostatic latent image is developed.

[0003]

However, the conventional developing magnet roll requires a shaft member that penetrates the magnet roll, and this shaft member must be formed longer than the magnet roll. It was difficult to ensure accuracy. Further, there are also problems that flanges provided at both ends of the sleeve for rotational driving are different between left and right, so that the number of parts is increased and assembly is troublesome.

Therefore, an object of the present invention is to use two shaft members of the same shape which are shorter than the magnet roll and to use common flanges at both ends of the sleeve to improve the accuracy of the magnet roll and the assemblability. It is to plan.

[0005]

In order to achieve the above object, a magnet roll for an image forming apparatus according to the present invention is provided with a conductive and non-magnetic cylindrical sleeve, fixed to both ends of the sleeve, and having a shaft hole. First and second flanges having the same shape, respectively, and a cylindrical magnet roll housed in the sleeve between the first and second flanges and having a plurality of magnetic poles on an outer peripheral portion have the same shape. Have
The first shaft is rotatably supported by the shaft hole of the first flange, and the tip is fixed to one end of the magnet roll, and is fixed in the shaft hole of the second flange. A second shaft whose tip is rotatably supported by the other end of the magnet roll.

[0006]

According to the magnet roll of the present invention, the first shaft rotatably supported by the shaft hole of the first flange is fixed to one end of the magnet roll and fixed to the shaft hole of the second flange. Since the second shaft is rotatably supported at the other end of the magnet roll, the magnet roll can be driven by the first shaft and the sleeve can be driven by the second shaft independently. In addition, the use of two shafts having the same shape eliminates the need for a shaft member that penetrates the magnet roll, and increases the precision of parts by forming each shaft shorter than a conventional shaft member. Furthermore, by making each of the two flanges and the shaft the same shape, the number of parts can be reduced, and the assemblability of the magnet roll can be improved and the cost can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a developing device 10 of an image forming apparatus such as a copying machine. The developing device 10 has an arrow 10
It is arranged to face the photoconductor 100 rotating in two directions.
Inside the developing device 10, a developing magnet roll 12, a supply roll 14, and a stirring roll 1 are sequentially arranged from the photoconductor 100 side.
6 are arranged. The developer containing the toner and the carrier (or the magnetic one-component developer containing only the toner) contained in the developing device 10 is supplied to the supply roll 14 while being stirred by the stirring roll 16. The developer supplied to the supply roll is conveyed by the rotation of the outer peripheral sleeve of the supply roll 14 and is supplied to the development magnet roll 12 at a portion facing the development roll 12.

The developing magnet roll 12 has a magnet roll therein. As shown in FIG. 2, the magnet roll 18 has a cylindrical shape having a plurality of magnetic poles (N, S) in the circumferential direction and integrally molded. However, as in the case of the magnet roll 18 shown in FIG. 3, a plurality of magnetic pole pieces 18b having a fan-shaped cross section may be fixed around the pipe 18a to form a cylindrical shape. The use of such cylindrical magnet rolls has the advantage that the precision of the parts is increased, and as a result, the magnetic force is stabilized.

As shown in FIG. 1, the developing magnet roll 12 has a cylindrical sleeve 20 which is driven to rotate in the direction of arrow 22 on the outer periphery of the magnet roll 18. The developer supplied to the developing magnet roll 12 is conveyed by the rotation of the sleeve 20 while being held on the sleeve 20 by the magnetic force of the magnet roll, and the conveyance amount is regulated by the regulating member 24. It is transported to the area 104. Then, the developer contacts the electrostatic latent image formed on the photoconductor 100 and develops the toner. The facing area 104
Is returned to the supply roll 14 and then collected by the stirring roll 16.

Next, the developing magnet roll 12 will be described in detail with reference to FIG. The cylindrical sleeve 20 is made of a conductive and non-magnetic material. At both ends of the sleeve 20, flanges 30 and 32 are fitted and fixed by caulking. The flanges 30 and 32 are made of a conductive resin and have the same shape. A shaft hole is formed in the center of each of the flanges 30 and 32 along the axial direction of the sleeve 20, and the inner peripheral surface of the shaft hole has a bearing function such as an impregnated slide bearing. I have. Sleeve 2 between these flanges 30, 32
The magnet roll 18 is accommodated in the housing 0.

Shafts 34 and 36 having the same shape are inserted into the shaft holes of the flanges 30 and 32, respectively. Each of the shafts 34 and 36 has an annular projection 38 at an intermediate portion. The first shaft 40 and the magnet roll 1 located on the opposite side of the magnet roll 18 with the annular projection 38 as a boundary.
It is divided into a second shaft portion 42 located on the eighth side. The second shaft portion 42 is further provided with a step, and a large diameter portion and a small diameter portion are formed.

The shaft 34 has an annular projection 38 between the magnet roll 18 and the flange 30, and a first shaft 40 is rotatably supported by a shaft hole of the flange 30. In addition, a second end, which is the other end of the shaft 34,
The large diameter portion of the shaft portion 42 is press-fitted or adhered into the center hole 44 at one end of the magnet roll 18 and fixed.

On the other hand, the annular projection 38 of the shaft 36 is outside the flange 32. And the second of the shaft 36
The large diameter portion of the shaft portion 42 is fixed in the shaft hole of the flange 32 by a method such as bonding or caulking, and the small diameter portion is fixed to the magnet roll 18.
Is rotatably supported by a bearing 46 press-fitted into a center hole 44 at the other end.

The thus-developed magnet roll 12 is assembled, for example, as follows. First,
The flange 30 is fixed to one end of the sleeve 20. Then, the magnet roll 18 in which the shaft 34 is fixed at one end in advance by press fitting or the like and the bearing 46 is press fitted at the other end,
The first shaft portion 40 of the shaft 34 is inserted into the shaft hole of the flange 30 by being inserted from the other open end of the sleeve 20. Next, the flange 32 is fixed to the other end of the sleeve 20. Then, after inserting the second shaft portion 42 of the shaft 36 into the shaft hole of the flange 32 and the bearing 46, the shaft 36 is fixed to the flange 32. By such a simple process, the assembly of the developing magnet roll 12 is completed.

As described above, in the developing magnet roll 12 of the present embodiment, the shaft 34 rotatably supported by the shaft hole of the flange 30 is fixed to one end of the magnet roll 18, and the shaft 34 is Since the fixed shaft 36 is rotatably supported by the other end of the magnet roll 18, the magnet roll 18 can be driven by the shaft 34 and the sleeve 20 can be driven by the shaft 36 independently. Also, by using two shafts 34, 36 having the same shape, a shaft member that penetrates the magnet roll 18 is not required, and the length of each shaft 34, 36 is made shorter than that of the conventional shaft member. Can be raised. In addition, each two flanges 3
By making the shafts 0 and 32 and the shafts 34 and 36 have the same shape, the number of parts can be reduced, and the assemblability of the magnet roll 12 can be improved and the cost can be reduced.

The magnet roll of the present embodiment is
Although described as being used for a developing roll, the present invention is not limited to this, and may be used for a supply roll or a stirring roll in a developing device, or used for a magnetic brush cleaning roller or a magnetic brush charging roller for a photoconductor. May be.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic configuration of a developing device arranged to face a photoconductor.

FIG. 2 is a perspective view of a magnet roll.

FIG. 3 is a perspective view of a modification of the magnet roll.

FIG. 4 is a sectional view showing a configuration of a magnet roll.

[Explanation of symbols]

12: magnet roll for development (magnet roll for image forming apparatus), 18: magnet roll, 20: sleeve, 3
0, 32... Flanges (first and second flanges), 3
4, 36... Shafts (first and second shafts), 4
6 ... Bearing.

Claims (1)

[Claims] 1. An electrically conductive, non-magnetic cylindrical sleeve, first and second flanges respectively fixed to both ends of the sleeve and having the same shape, each having a shaft hole, and the first and second flanges. A cylindrical magnet roll having a plurality of magnetic poles on an outer peripheral portion, each of which has the same shape, is rotatably supported by a shaft hole of the first flange, and has a distal end portion. A first shaft fixed to one end of the magnet roll, and inserted and fixed in a shaft hole of the second flange, and a tip end is rotatably supported by the other end of the magnet roll. A second shaft, and a magnet roll for an image forming apparatus.