JPH03265878A - Cylindrical assembling body for image forming device - Google Patents

Abstract

PURPOSE:To secure the sufficient magnetic force on the outside face of a cylindrical body even if this cylindrical assembling body is miniaturized in size and diameter and to prevent the abuse of the turbulence of the magnetic force by slidably supporting a magnetic roller by means of the cylindrical body via a sliding member. CONSTITUTION:In the developing roller 10 of a developing unit, the magnetic roller 12 is held in a fixed state inside a developing sleeve 11 as the cylindrical body, and a developer is held on the circumference of the developing sleeve 11 by the magnetic force of the magnetic roller 12, and the developing sleeve 11 is rotated in a fixed direction to supply the developer to an image carrier side. At this time, the sliding member 15 is attached to the outer periphery of the magnetic roller 12, and the magnetic roller 12 is slidably supported by the developing sleeve 11 via the sliding member 15. The distortion, etc., of the magnetic roller 12 are prevented, and a gap between the developing sleeve 11 and the magnetic roller 12 is uniformly held. Thus, the functions of the cylindrical assembling body are sufficiently exhibited even if it is miniaturized.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a cylinder of an image forming apparatus, which is composed of a magnetic roller and a cylinder having the magnetic roller inside, and is used in an image forming apparatus such as a copying machine. Regarding the assembly.

(Prior Art) An example of a cylindrical assembly of an image forming apparatus including a magnet roller and a cylindrical body having the magnet roller inside will be described using a developing roller of a developing device of an electrophotographic copying machine as an example.

A copying machine is provided with a developing device for visualizing an electrostatic latent image formed on a photosensitive tram, which is an image carrier, using a developer (toner). A developing roller is provided in the developing device, and the toner in the developing device is supplied toward the photosensitive drum by the action of the magnetic force of the developing roller.

As shown in FIG. 3, this developing roller is composed of a cylindrical developing sleeve 100 that rotates in a fixed direction and a MacNet I roller 101 disposed within the developing sleeve 100. The magnetic roller 101 is fixed to both ends of its core metal part 101a or to the developing device main body 110, and the developing screen 100 has a slight gap with the magnetic part 101b of the magnetic roller 101, and
01, and both ends of the bearing member 10 are arranged so as to cover the bearing member 10.
2, 102, and is pivotally supported on the developing device main body 110.

Here, the rigidity of the magnet roller 101 is maintained by penetratingly adhering a core metal part 101a made of a metal material such as iron to a relatively soft cylindrical magnet part 101b made of rubber or vinyl chloride.

(Problem to be solved by the invention) However, with the recent demand for smaller copying machines, there has also been a demand for smaller developing units, which has also led to demands for smaller developing rollers (smaller diameter). ing. For this reason, if a conventional size (diameter) is used for the core metal part 101a, the thickness of the magnetic net part 101b becomes thinner, and the magnetic force necessary for development cannot be obtained, resulting in a decrease in the developing ability. It will come to life.

Furthermore, if the diameter of the core metal portion 101a is made smaller in proportion to the reduction in the diameter of the developing roller, the entire magnetic roller 101 will lack rigidity, and the magnetic roller 101 will bend due to its own weight, etc., and the developing screen 100 and the magnetic roller The gap between 101 becomes uneven, and the developing three 710
This may lead to problems such as non-uniform magnetic force on the 0 surface, resulting in poor development. When the deflection of the magnet roller 101 further increases, as the developing screen 100 rotates, the magnetic roller 101 and the developing screen 100 rub against each other.
This also causes unnecessary torque to be generated in the developing sleeve 100.

Further, the above is not limited to the developing roller of the developing device, but also applies to the cleaning roller of the cleaning device used for cleaning the photosensitive tram.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a cylindrical assembly for an image forming apparatus consisting of a magnet roller and a cylindrical body, which can sufficiently exhibit its functions even when downsized. It is in.

(Means for Solving the Problems) In order to achieve the above object, the present invention comprises a magnet roller with low rigidity and a cylindrical body having the magnet roller inside, and at least one of these rotates to form an image. In the cylindrical assembly of the device, a sliding member is attached to the outer peripheral surface of the magnet roller, and the magnet roller is slidably supported by the cylindrical body via the sliding member.

(Function) For example, in the developing roller of a developing device, a magnetic roller is held in a fixed state within a cylindrical developing sleeve, and the developer is held in the developing sleeve layer by the magnetic force of the magnetic roller, and the developing By rotating the screen in a certain direction, this developer is supplied toward the image carrier.

In this case, in order to generate a uniform magnetic force in the developing sleeve layer, the gap between the magnet roller and the developing sleeve must be uniform, or if the rigidity of the magnetic roller is small, the magnetic roller may be deflected, etc. Maintaining uniform gaps becomes difficult.

Therefore, by attaching a sliding member to the outer circumferential surface of the magnet roller and slidingly supporting the magnet roller on the developing sleeve via the sliding member, bending of the magnet roller can be prevented and the developing sleeve can The gap with the magnet roller is maintained evenly.

(Example) Examples of the present invention will be described below with reference to the accompanying drawings, taking a developing roller of a developing device as an example.

FIG. 1 is a cross-sectional view of the area around a developing roller in the developing device, and FIG. 2 is a cross-sectional view of the developing device incorporated in the image forming apparatus.

As shown in FIG. 2, the developing device 2 is disposed on one side of the photosensitive tram 1, which is an image carrier that rotates in a fixed direction.
A developing roller 10 that supplies developer (toner) T to the photosensitive tram 1, a magnetic tray F 20 that regulates the layer thickness of toner held around the developing roller 10, and a magnetic plate 20 and the developing roller 10. It is composed of a developing device main body 30 that holds the toner and also serves as a part of a hopper for storing toner.

The developing roller 10 has a plurality of magnetic poles N1. A magnet roller 12 with a circular cross section having N2°S, , S, and a cylindrical developing sleeve 11 that covers the outer periphery of the magnet roller 12.
The developing sleeve 11 is composed of a developing device main body 3 and the like.
0, or is the magnetic roller 1 rotatably supported?
2 is fixed to the developing device main body 30. Since the toner T in the developing device main body 30 is a magnetic toner, the toner is easily held around the developing sleeve 11 via the magnetic roller 12 by magnetic force.

That is, the toner T held around the developing sleeve 711 via the magnetic poles N2 and S2 of the magnetic roller 12 is moved toward the magnetic plate 20 as the developing sleeve 11 rotates, but the magnetic plate 20 and the magnetic roller 12 Due to the action of the magnetic pole N1, the toner T on the developing sleeve 11 is directed toward the photosensitive tram 1 in a state where the layer thickness is regulated to be thin. Then, by the action of the magnetic pole S of the magnet roller 12, the toner T on the developing screen 11 forms a magnetic flag, and is moved toward the electrostatic latent image on the photosensitive tram 1 and subjected to a developing operation.

Next, the specific structure of the developing roller 10 and its attachment state to the developing device main body 30 will be explained with reference to FIG.

The developing screen 11 is made of a non-magnetic material such as aluminum or stainless steel, and bearing members 13 are provided at both ends thereof or on the inner peripheral surface of the support recesses 31 and 32 of the developing device main body 30.
．． It is pivotally supported via 14. In addition, the developing sleeve 11
A drive gear 14 for rotating the developing sleeve 11 is attached within the supporting portion 31 at one end, and the driving gear 14 is rotated by a power transmission means (not shown), so that the developing sleeve 11 is rotated at a constant speed. It is now possible to do so.

The magnet roller 12 is made by extruding a relatively soft and low-rigidity magnet material such as rubber-based or vinyl chloride-based material into a solid roller shape, and has end surfaces 12a at both ends thereof,
12a is fixed to support protrusions 31a and 32a protruding from the ends of support recesses 31 and 32 of the developing device main body 30.

Note that the support protrusion 31a passes through the center of the drive gear 14.

Now, in order to uniformly apply the magnetic force of the magnet roller 12 to the developing sleeve 11, is it necessary to maintain the gap t between the inner surface of the magnet roller 12 and the outer surface ffJf of the developing sleeve 11 at a constant value? 12
Since it is made of a material with relatively low rigidity, it is easily bent due to its own weight, and it is not necessarily easy to maintain a constant gap t between the developing sleeve 11 and the magnet roller 12.

Therefore, a sliding member 15.15.15 having a substantially concave thickness is fixed to the outer circumferential surface of the middle part and both ends of the magnet roller 12 above the gap between the magnet roller 12 and the developing sleeve 711, and the sliding member 15.15. Member 15. The magnet roller 12 is slidably supported on the inner surface of the developing screen 11 via..., and the gap t between the developing screen 11 and the magnet roller 12 is maintained at a constant value.

The sliding member 15 is made of a material with high sliding properties, such as polyacetal resin, ultra-high molecular weight polyethylene, or heat-shrinkable tune of polyethylene terephthalate, so that the frictional resistance between it and the developing screen 11 can be kept as low as possible. It looks like this.

Therefore, even if the magnet roller 12 is made of a relatively soft and low-rigidity material, and a core made of a highly rigid metal material is not attached to the magnet roller 12, the magnet roller 12 sliding member 15. Since the developing sleeve 11 can be slidably supported through the magnetic roller 10, the gap between the developing sleeve 11 and the magnet roller 12 can be maintained at a constant value, and the developing device 2 having this developing roller 10 can be used properly. image formation.

In addition, the separating magnetic roller 1 does not require a core metal etc.
The magnetic force of the magnetic roller 2 can be increased, the diameter of the magnetic roller 2 can be reduced, and the magnetic roller 12 can be manufactured simply by extrusion molding, which reduces the cost of the device and the number of manufacturing steps. This means that it is possible to achieve the following.

Above, the developing sleeve 11 rotates and the magnet roller 1
Although the description has been made regarding the developing roller 10 in which the developing sleeve 11 is fixed and the magnetic roller 12 rotates, the developing roller 10 in which the developing sleeve 11 is fixed and the magnetic roller 12 rotates, or the developing roller 10 in which both the developing sleeve 11 and the magnetic roller 12 are rotated in opposite directions. Of course, the present invention can also be applied to the rotating developing roller 10.

Further, the present invention includes not only the developing roller 10 of the developing device 2, but also other devices in the image forming apparatus, such as a cleaning device that cleans residual toner on the photosensitive tram l, and includes a magnetic roller and a cleaning sleeve. Of course, it can also be applied to cleaning rollers.

Furthermore, the present invention is applicable not only to image forming apparatuses but also to general cylindrical assemblies in which a magnetic roller is held within a cylindrical body and at least one of these is rotated.

(Effects of the Invention) As is clear from the above description, according to the present invention, in the cylindrical assembly of an image forming apparatus having a magnet roller with low rigidity inside the cylindrical body, the magnet roller is attached to the cylindrical body via a sliding member. Since the magnetic roller is slidably supported, the magnetic roller can be properly disposed within the cylindrical body even if the magnetic roller has low rigidity.

Therefore, even if the magnet roller is made smaller and smaller in diameter, it is possible to ensure sufficient magnetic force on the outer surface of the cylindrical body with this magnet roller because no core metal etc. is required, and the magnet roller does not bend, and the cylinder that is caused by the deflection of the magnet roller It is possible to prevent harmful effects such as disturbance of magnetic force on the external surface of the body.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the area around the developing roller of a developing device, FIG. 2 is a sectional view of the area around the developing device in an image forming apparatus, and FIG. 3 is a sectional view of the area around the developing roller of a developing device according to the prior art. 10...Developing roller (cylindrical assembly), 11... Cylindrical body (developing sleeve), 12... Magnet roller 15
-...Sliding member.

Claims (5)

[Claims] (1) In a cylindrical assembly of an image forming apparatus that is composed of a magnet roller with low rigidity and a cylindrical body having the magnet roller inside, at least one of which rotates, there is a sliding member on the outer peripheral surface of the magnet roller. 1. A cylindrical assembly for an image forming apparatus, characterized in that a magnet roller is slidably supported on the cylindrical body via the sliding member. (2) the magnetic roller does not have a metal core;
The cylindrical assembly for an image forming apparatus according to claim 1, wherein the magnet roller is made of a rubber-based or plastic-based material. (3) The cylindrical assembly for an image forming apparatus according to claim 2, wherein the magnet roller is molded by extrusion molding technology. (4) The cylindrical assembly for an image forming apparatus according to claim 1, 2 or 3, wherein the cylindrical body is a developing sleeve of a developing device. (5) The cylindrical assembly for an image forming apparatus according to claim 1, 2 or 3, wherein the cylindrical body is a cleaning sleeve of a cleaning roller of a cleaning device.