JPH019960Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a magnetic brush developing device for an electronic copying machine.

(Prior Art) In a developing magnet roller that forms a magnetic brush in a magnetic brush developing device using a two-component developing method for an electronic copying machine, a fixing roller as shown in FIGS. 1 and 2 has conventionally been used. A magnetic shaft and a rotating sleeve bearing are used. That is, the magnet roller 3, which consists of a fixed magnet shaft 1 to which the rod-shaped magnet 1a is fixed, and a rotating sleeve 2, is disposed inside an agitated developing device (not shown), so that it supports the fixed magnet shaft 1. If only the bearing part 4 was used, the scattered toner a would enter the bearing part 4 and adhere to the lubricating oil applied to the bearing 5, which would have a significant negative effect on the rotation and life of the bearing 5.

Therefore, in order to prevent the intrusion of toner, various types of bearing parts have been considered in the past, which are a combination of an oil seal and a bearing.

(Problem to be solved by the invention) However, in the case of a conventional bearing that combines an oil seal and a bearing, a space is required to accommodate the bearing and the oil seal, and the oil seal is attached to the shaft. Because they are in contact with each other, the oil seal deteriorates and becomes unable to seal after long-term use, and must be replaced periodically.Furthermore, the use of bearings and oil seals is expensive. It had

The present invention was developed to solve the above problems, and its purpose is to prevent toner from entering the bearing with a relatively simple structure, and to be able to withstand high-speed rotation and long-term use. It is an object of the present invention to provide a magnetic brush developing device.

[Structure of the idea]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a fixed magnet shaft made of a non-magnetic material in which a rod-shaped magnet is integrally formed in the axial direction in a developing device in which toner is stored, and a fixed magnet shaft made of a non-magnetic material. A non-magnetic material integrally formed with a cylindrical member made of a non-magnetic material that covers the outer periphery of the shaft in the axial direction, and a bearing portion that is fixed to the end of this cylindrical member to cover the fixed magnet shaft and rotatably support it. and a flange for preventing toner from entering the fixed magnet shaft through a bearing portion of the flange, wherein the bearing portion is a bearing of a low friction coefficient member that rotatably supports the fixed magnet shaft. ,
A cylindrical sleeve of a magnetic member is formed in close contact with the outer periphery of the bearing.

(Function) That is, with the above structure, toner adheres to the exposed portion of the sleeve along with the magnetic carrier and rotates around the fixed magnet shaft, forming a cylindrical carrier brush.

Therefore, the carrier brush can prevent the flying toner from entering from the bearing.

(Example) The present invention will be described below based on an example shown in FIGS. 3 and 4. 3 and 4 are a front view and a side view showing the bearing portion of the developing magnet roller. In FIG. 3, reference numeral 11 denotes a non-magnetic fixed magnet shaft supported by a pair of support frames (not shown) provided inside the developing device, and having a bar-shaped magnet 11a fixed in the axial direction. A cylindrical member 12 made of a non-magnetic material (for example, aluminum material) is provided on the outer periphery of the magnet shaft 11 with an appropriate gap, a flange 15 made of a non-magnetic material fixed to one end of the cylindrical member 12, and a flange 15 made of a non-magnetic material fixed to one end of the cylindrical member 12. The fixed magnet shaft 11 is covered by a conductive holder 16 fixed to the other end of the member 12.

The flange 15 has a low friction coefficient member (for example, Teflon (registered trademark)) that supports one end of the fixed magnet shaft 11 in the center.
A cylindrical bearing 13 and a bearing part 20 made of a cylindrical sleeve 14 made of a magnetic member (for example, magnetic stainless steel) are formed in close contact with the outer periphery of the bearing 13, and rotatably support one end of the fixed magnet shaft 11. I'm starting to do that.

On the other hand, the holder 16 rotatably supports the other end of the fixed magnet shaft 11 and connects the developing bias power source 1 via a conductive bearing 17.
8 is connected.

Therefore, the cylindrical member 12 and the flange 15
and the holder 16 integrally has a bias power supply 18
The magnet is configured to be able to rotate in the direction shown by the arrow around the fixed magnet shaft 11 by receiving power from the magnet.

Note that 19 is a non-conductive support (for example, a synthetic resin member) that rotatably supports the holding body 16 .

Next, the operation of the present invention based on the above configuration will be explained. The magnetic carrier a in the developer adheres to the surface of a magnet roller, ie, a cylindrical member 12, housed in a developing device (not shown) by magnetic force generated from an internal bar-shaped magnet 11a.
At this time, toner (not shown) is also electrostatically attached to the carrier a.

Further, the cylindrical member 12 is attached to the fixed magnet shaft 1.
1, the cylindrical sleeve 14 of the bearing portion 20 made of a magnetic material will rotate around the bar-shaped magnet 11.
In order to be magnetized by receiving the magnetic force of a, the sleeve 1
The scattered magnetic carrier a adheres to the exposed surface of 4. This sleeve 14 is attached to the fixed magnet shaft 1.
1, the attached magnetic carrier a rotates around the fixed magnet shaft 11, forming a so-called cylindrical carrier brush.

Toner is attached to the exposed portion of the sleeve 14 along with the magnetic carrier a, but once the magnetic carrier a is attached in a brush-like manner, this carrier brush further scatters the toner from the bearing 13 into the inside of the magnet roller. Since it acts to prevent intrusion, it has the same effect as an oil seal.

[Effect of idea]

As explained above, according to the present invention, the cylindrical member and the cylindrical sleeve rotate around the fixed magnet shaft via the bearing, and the toner adheres to the exposed portion of the sleeve together with the magnetic carrier, forming a carrier brush. Therefore, it is possible to prevent toner from entering the magnet roller without using an oil seal.

Therefore, this provides excellent effects in that the magnet roller can rotate at high speed and have a long life.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of a magnet roller showing the main parts of a conventional magnetic brush developing device, Fig. 2 is a longitudinal sectional front view of a bearing part showing a part thereof, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a vertical sectional front view of the magnet roller shown, and FIG. 4 is a left side view thereof. 11...Fixed magnet shaft, 13...Bearing, 1
4... Sleeve, 15... Flange, a... Magnetic carrier, 20... Bearing portion.

Claims (1)

[Scope of utility model registration request] A fixed magnet shaft made of a non-magnetic material in which a rod-shaped magnet is integrally formed in the axial direction in a developing device in which toner is stored, a cylindrical member made of a non-magnetic material that covers the outer periphery of the fixed magnet shaft in the axial direction, and this cylindrical member. and a non-magnetic flange integrally formed with a bearing portion which covers and rotatably supports the fixed magnet shaft by being fixed to the end of the magnet shaft, and the toner is supplied to the fixed magnet shaft through the bearing portion of the flange. In the device for preventing intrusion, the bearing portion includes a bearing made of a low friction coefficient member that rotatably supports the fixed magnet shaft, and a cylindrical sleeve made of a magnetic member formed in close contact with the outer periphery of this bearing. A magnetic brush developing device characterized by being provided with a magnetic brush developing device.