JPH04317086A - Sealing structure around powder carrying rotary body - Google Patents

Abstract

PURPOSE:To improve sealing between especially, both side port edges in the axtial direction of a powder carrying rotating body and the powder carrying rotating body, on the supplying or recovery port of a casing for supplying or recovering the powder on which the powder carrying rotating body is applied, and to surely, prevent the leaking out of the powder on the sealing part. CONSTITUTION:The Y surface opposite to the sealing part holding a fixedly provided sealing member 62 between the powder carrying rotating body 11, and the port edges 2d of both sides in the axtial direction of the powder carrying rotating body 11 of the port part 2a supplying or recovering the powder of a casing supplying or recovering the powder, is made of a material 61 having friction lower than that of the material of the powder carrying rotary body 11.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a seal structure around a powder-carrying rotating body, and more specifically to a developing roller of a developing device used in an image forming apparatus that forms images by electrophotography such as a copying machine, facsimile machine, or printer. Alternatively, it is used in a seal structure for a photosensitive drum or the like that forms an electrostatic latent image for development by this developing roller.

0002

[Prior Art] Since a developing roller handles a large amount of fine developer and uses it for development, leakage of the developer between the developer casing and the developer casing that supplies this developer becomes a major problem, and conventional methods have been used to prevent this. Various seal structures have been proposed.

For example, an example of a developing device using a one-component developer is disclosed in FIGS. 2 and 4 of Japanese Patent Application Laid-open No. 63-235970.

[0004] In this developing roller made of metal such as aluminum, the peripheral surface of the developer carrying area facing the developer supply port of the developer casing is made with a so-called satin finish to increase the conveying force and to ensure sufficient developer supply. I'm trying to do it.

On the other hand, smooth developer-free areas are provided on both sides of the developer-carrying area of the developing roller, and these areas face the left and right edges of the developer supply port of the developer casing. I have to.

Between the developing roller and the upper and lower edges of the developer supply port of the developer casing, there is a developer which extends from the upper edge onto the developer carrying area and the developer non-carrying area of the developing roller and comes into pressure contact therewith. The elastic blade for regulating the layer thickness of the developing roller and the sealing piece that extends from the lower lip onto the developer carrying area and non-developing area of the developing roller and are in pressure contact with each other are used to seal the developing roller and developer casing. The space between the left and right mouth edges of the mouth part is sealed by fixed seal pads that are attached to the left and right mouth edges so that they come into pressure contact with the smooth circumferential surface of the developer-free area of the developing roller. are doing.

[0007] Accordingly, the gap between the developing roller and the developer supply port of the developer casing can be sealed around the entire circumference of the opening, thereby preventing leakage of the developer.

[0008]

However, even with the above-mentioned sealing structure, a problem arises in that the developer sometimes leaks to the sides.

The developer non-carrying area of the developing roller has a smooth circumferential surface and is in close contact with seal pads on both left and right edges of the developer supply port of the developer casing. However, the developer carried and conveyed in the developer carrying area of the developing roller tends to enter between the seal pad and the smooth surface of the developer non-carrying area, which is supposed to be in close contact, and this causes the developer to enter the seal pad. It was confirmed that the fluid moves outward as the smooth surface rotates and eventually leaks out to the sides.

As a result of various experiments and studies conducted by the present inventors on this point, it has been found that although the developer non-carrying area of the developing roller is formed smoothly, the developer that tries to enter between it and the seal pad The main cause seems to be the transport force exerted on the agent.

Therefore, it is an object of the present invention to provide a sealing structure around a powder-carrying rotating body that can solve the above-mentioned conventional problems by suppressing such conveying force. .

0012

[Means for Solving the Problems] The first invention of the present application is provided so that a part of the casing for supplying or collecting powder faces the mouth for supplying or collecting the powder, and the powder is supplied through the mouth. In a powder-carrying rotary body that supports and conveys powder or collects the powder that is being carried and is being conveyed through the mouth, the mouth faces the mouth edges on both sides of the powder-carrying rotor in the axial direction of the mouth. The opposing surfaces of the seal portions between which the fixed seal material is sandwiched are made of a material having lower friction than the material forming the powder-carrying rotating body itself.

[0013] A second invention of the present application is characterized in that the low-friction material forming the surface facing the seal portion of the powder-carrying rotating body is a resin material.

[0014] A third invention of the present application is characterized in that the sealing material is made of a material with higher friction than the low-friction material forming the surface facing the seal portion.

[0015]

[Operation] According to the above structure of the first invention of the present application, the mouth portion of the casing that supplies or collects powder is fixed between the rims of both sides in the axial direction of the powder-carrying rotating body. The surface facing the seal portion of the powder-carrying rotating body, on which the sealing material is sandwiched, is made of a material with lower friction than the metal material of the powder-carrying rotating body, and the powder does not enter between the sealing material and the sealing material. When attempting to enter the powder, the surface facing the seal has low friction, so even if it is rotated as part of the developing roller, the conveying force exerted on the powder attempting to enter is small, and the powder is pushed to the side of the sealing material. By making the powder easily captured by the powder and difficult to move, it is possible to sufficiently prevent the powder from moving outward and leaking to the outside.

According to the above configuration of the second invention of the present application, the first
Furthermore, since the low-friction material forming the facing surface of the seal part is a resin material, it can be applied by coating or fitting on the required parts of the powder-carrying rotating body, thereby reducing laborious work and high precision. It is possible to obtain the required low-friction seal portion facing surface without requiring extensive processing. In addition, since it is more elastic than metal, it can adhere well to the boundary with the powder carrier, making it difficult to create gaps where developer can enter.

According to the above configuration of the third invention of the present application, the first
Alternatively, in the second invention, the sealing material is made of a material having higher friction than the low-friction material forming the surface facing the seal portion, so that powder that tries to enter between the surface of the powder-carrying rotating body and the surface facing the seal portion is prevented. This improves the ability of the body to capture the powder on the sealing material side, effectively preventing the powder from being entrained on the side facing the sealing part of the rotating powder-carrying rotating body, and further preventing powder from leaking to the outside. can do.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A developing device as an embodiment to which the present invention is applied will be described below.

FIG. 5 shows an image forming mechanism equipped with the developing device. This image forming mechanism uses a one-component developer, and a developer casing 2 and a waste toner casing 3 are arranged on both sides of a photosensitive drum 4.

The photosensitive drum 4 has a photoconductive layer made of selenium or an organic photoconductive material formed on the surface of a metal base such as aluminum, and the surface is uniformly charged by a charger 52 located at the top. As shown at 23, an electrostatic latent image is formed by imagewise exposure. This electrostatic latent image is developed with a developer supplied from the developer casing 2, and becomes a developed image.

This developed image is transferred onto a transfer sheet 37 by a transfer charger 36 located below the photosensitive drum 4, and then fixed by a fixing device (not shown) to complete image formation.

A developing roller 11 for developing the electrostatic latent image formed on the photosensitive drum 4 is provided at the toner supply port 2a of the developer casing 2 facing the photosensitive drum 4.
It is pivotally supported on the side wall of the developer casing 2 by a shaft 14 .

A development gap is provided between the development roller 11 and the photosensitive drum 4 for non-contact development using a one-component non-magnetic developer.

A developer supply paddle 15 is provided in the developer casing 2 to agitate the developer in the developer casing 2 while supplying it to the fur brush 13, and this includes stirring blades 17 to prevent the toner from forming into blocks. is installed.

At the upper edge 2b of the toner supply port 2a of the developer casing 2, an elastic blade 41 is provided which extends to the circumferential surface of the developing roller 11 and presses against it.

The elastic blade 41 forms a thin layer of the developer supplied by the fur brush 13 onto the developing roller 11 to a predetermined thickness, and is made of rubber blades such as urethane rubber or silicone rubber, phosphor bronze for springs, or spring steel. Metallic blades such as the following are useful.

The upper end of the elastic blade 41 is attached by adhesive or the like to a metal support member 42 extending between the side walls of the developer casing 2, and the lower end is pressed against the surface of the developing roller 11.

A seal piece 25 is provided on the lower edge 2c of the toner supply port 2a of the developer casing 2, and extends over and presses onto the developing roller 11. This seal piece 25 is made of polyethylene terephthalate (PET) or the like, and allows residual toner carried on the developing roller 11 and subjected to development on the photosensitive drum 4 to pass through into the toner supply port 2a. To prevent the developer from coming out from 2a.

By the way, in FIG. 1, the developing roller 11 is made of aluminum or stainless steel, and the developer carrying area X on the central side in the longitudinal direction facing the toner supply port 2a is formed with a satin surface by sandblasting or the like. It is designed to be advantageous for carrying and transporting.

Both ends of the developing roller 11 on both sides of the developer carrying region It exists as an area.

For this reason, the developer non-carrying area Y is formed of a material having lower friction than the metal material of the developing roller 11, so that the conveying force for the developer in this area is minimized. Although the developing roller 11 is made of metal in this embodiment, it is not limited to this.

In this embodiment, as shown in FIG. 1, the developer non-carrying area Y of the developing roller 11 is made into a small diameter portion 11a, and a resin collar 61 is fitted to this to form a low friction surface. are doing. For example, polyacetal is used as the resin material, and by performing the above-mentioned fitting in a press-fitting manner, the shoulder surface of the developer carrying area This prevents objects from entering or being bitten.

However, the color 61 is the same as the developing roller 1.
The required pressure-bonding position of the first developer carrying area X onto the shoulder surface can also be maintained by a snap ring or the like attached to the small diameter portion 11a or the base of the shaft 14.

Further, the outer diameters of the collar 61 and the developer carrying area X of the developing roller 11 are approximately the same at least at their crimped portions. This is suitable for stabilizing the developing function and stabilizing the developer leakage prevention function.

In this case, by simply using a molded collar 61, the friction coefficient of the surface of the developer non-carrying area Y is much smaller than when aluminum or stainless steel is mirror-finished.

In FIGS. 3 and 4, the developer non-carrying area Y of the developing roller 11 is located at the left and right edges 2d of the toner supply port 2a.
The left and right side opening edges 2d
The seal pad 62 is in pressure contact with the seal pad 62 attached to the seal pad 62 to form a seal portion that prevents the developer from leaking to the side.

Further, on the inner surface of the tip of the elastic blade 41, the seal pad 62 on the left and right edges 2d of the toner supply port 2a and the developer non-carrying area Y of the developing roller 11 are formed.
An auxiliary seal pad 63 is provided to seal the gap between the elastic blade 41 and the elastic blade 41.

As described above, the area between the entire circumference of the lip of the toner supply port 2a of the developer casing 2 and the developing roller 11 is sealed by the seal piece 25, the elastic blade 41, the seal pad 62, and the auxiliary seal pad 63, and the developer is leakage is prevented.

In the conventional structure, especially the developer non-carrying area Y of the developing roller 11 and the left and right edges 2d of the toner supply port 2a.
The problem is that the developer tends to leak out between the two. However, the above-mentioned seal structure of this embodiment eliminates such problems.

To further explain this with reference to FIGS. 3 and 4, the developer is transferred to the developer carrying area X of the developing roller 11.
Even if the developer tries to enter between the developer non-carrying area Y and the seal pad 62 or the auxiliary seal pad 63 due to the strong conveyance force caused by the developer, the friction on the surface of the developer non-carrying area Y is much smaller, so this part will be blocked by the developing roller. Even if it is rotated as part of the developer 11, the conveying force exerted on the developer that is about to enter is small.

For this reason, the developer that tries to enter is easily captured by the seal pad 62 and the auxiliary seal pad 63, and is less likely to be attached to the surface of the developer-free region Y of the developing roller 11. It is possible to sufficiently prevent the developer from moving between the carrying area Y and the seal pad 62 and the auxiliary seal pad 63, especially outward migration. It is possible to sufficiently prevent leakage to the sides.

Furthermore, the seal pad 62 and the auxiliary seal pad 63 are made of foamed urethane rubber or the like, and have a higher coefficient of friction than the developer non-carrying area Y, so they have excellent ability to capture the developer. The effect of preventing leakage of developer is even higher. Note that it is advantageous for the foamed urethane rubber to have closed cells. This is because the friction is large, and just a little compression can prevent the developer from escaping or leaking through air bubbles.

With the structure that can sufficiently prevent the developer from leaking out to the side as described above, it is not necessary to forcefully press the seal pad 62 and the auxiliary seal pad 63 against the developer non-carrying area Y. Even in the case of a structure in which the agent non-carrying region Y rotates, the load torque on the developing roller 11 can be reduced.

Furthermore, the degree of compression of the seal pad 62 is reduced, so that the elastic deformability is not impaired, and the gap between the seal pad 62 and the developing roller 11 is maintained at the overlapped portion with the seal piece 25 as shown in FIGS. 3 and 4. It is possible to prevent the formation of a stepped portion that would cause a gap, and the sealing performance is improved in this respect as well.

A cleaning blade 7 extending from the upper edge 3b of the toner collecting shoe 3a is in pressure contact with the portion of the waste toner casing 3 of the photosensitive drum 4 that is opposed to the toner collecting port 3a. The residual toner scraped off from the surface of the photosensitive drum 4 after transfer by the cleaning blade 7 is collected into the waste toner casing 3.

For this collection, a paddle 8 is provided near the bottom of the waste toner casing 3 behind the photosensitive drum 4.
The toner scraped off from the photosensitive drum 4 is scraped into the waste toner casing 3.

A seal piece 26 is provided at the lower edge 3c of the collection port 3a of the waste toner casing 3, and its tip is pressed against the surface of the photosensitive drum 4.

This seal piece 26 is similar to the seal piece 25, and the residual toner on the photosensitive drum 4 passes through the cleaning blade 7 without difficulty, but the residual toner that is scraped off by the cleaning blade 7 and falls off. It serves to receive the toner, guide it into the waste toner casing 3, and prevent it from slipping out below the waste toner casing 3.

Furthermore, the cleaning blade 7 and the seal piece 26 or the sealing material provided on the left and right edges of the toner collection port 3a are added to prevent the toner collection port 3a of the waste toner casing 3 from being connected to the photosensitive drum 4. The gap is sealed to prevent collected toner from leaking out.

The sealing structure around the developing roller 11 and the entire circumference of the mouth edge of the toner supply port 2a of the developing device casing 2 is such that the sealing structure between the photosensitive drum 4 and the waste toner casing 3
By adopting a sealing structure between the toner collection port 3a and the entire circumference of the toner collection port 3a, similar effects can be achieved.

For this purpose, both ends of the photosensitive drum 4 are modified to resemble both ends of the developing roller 11, and the toner collection port 3 is
Fixed seal pads may be provided on the left and right mouth edges of a.

In short, the present invention is not limited to the description of the embodiments, but can be applied to any sealing structure between a powder-carrying rotor and the mouth facing the rotating body for supplying or collecting powder. Can be done.

[0053]

Effects of the Invention According to the first invention of the present application, a fixed seal is provided between the supply port or collection port of the casing for supplying or collecting powder and the axially opposite edges of the powder carrying rotor. The surface of the seal portion facing the sealing member of the powder-carrying rotating body is made of a material with lower friction than the material of the powder-carrying rotating body, and the powder is sandwiched between the sealing member and the sealing member. When a powder tries to enter, the surface facing the seal part has low friction, so even if it is rotated as a part of the developing roller, the conveying force exerted on the powder trying to enter is small, and this powder By making the powder easily caught on the side of the material and difficult to move, it is possible to sufficiently prevent the powder from moving outward and leaking to the outside, thereby preventing wasted developer consumption and leakage to the outside. Eliminates surrounding stains caused by leaked developer.

According to the above configuration of the second invention of the present application, the first
Furthermore, since the low-friction material forming the facing surface of the seal part is a resin material, it can be applied by coating or fitting on the required parts of the powder-carrying rotating body, thereby reducing laborious work and high precision. It is possible to obtain the necessary low-friction facing surface of the seal portion without requiring extensive machining, and the required structure can be easily and inexpensively provided.

According to the above configuration of the third invention of the present application, the first
Alternatively, in the second invention, the sealing material is made of a material having higher friction than the low-friction material forming the surface facing the seal portion, so that powder that tries to enter between the surface of the powder-carrying rotating body and the surface facing the seal portion is prevented. This improves the ability of the body to capture the powder on the sealing material side, effectively preventing the powder from being entrained on the side facing the sealing part of the rotating powder-carrying rotating body, and further preventing powder from leaking to the outside. can do.

[Brief explanation of drawings]

FIG. 1 is a front view of a portion of a developing roller to which the present invention is applied, showing a main part thereof in cross section.

FIG. 2 is a front view showing an installed state of the developing roller shown in FIG. 1;

FIG. 3 is a cross-sectional view of a portion of the developing device showing an installed state of the developing roller shown in FIG. 2;

FIG. 4 is an exploded perspective view of a portion of the developing device shown in FIG. 3;

FIG. 5 is a sectional view showing a schematic configuration of an electrostatic image forming apparatus in which the developing device shown in FIGS. 3 and 4 is used.

[Explanation of symbols]

2. Developer casing 2a Toner supply port 2d Left and right mouth edges 11 Developing roller 61 color 62 Seal pad Y Developer non-supporting area

Claims (3)

[Claims] Claim 1: A casing for supplying or collecting powder, which is provided so as to partially face the mouth for supplying or collecting powder, and for supporting and transporting or supporting the powder supplied through the mouth. In the powder-carrying rotating body that collects the powder being conveyed through the mouth, a fixed sealing material is provided between and facing the mouth edges on both sides of the powder-carrying rotating body in the axial direction of the mouth. A seal structure around a powder-carrying rotor, characterized in that the opposing surface of the seal portion to be sandwiched is formed of a material having lower friction than the material forming the powder-carrying rotor itself. 2. The seal structure around the powder-carrying rotor according to claim 1, wherein the low-friction material forming the surface facing the seal portion of the powder-carrying rotor is a resin material. 3. The sealing material is made of a higher friction material than the low friction material forming the surface facing the seal portion.
Seal structure around the powder-carrying rotating body described in .