JPH0546017A - Layer regulating device - Google Patents

Abstract

PURPOSE:To accomplish the regulation of a layer which is uniform and excellent in aging stability by simple and small-sized layer regulating structure. CONSTITUTION:In a layer regulating device where developer carried and fed on the surface of a developer carrier 11a is regulated to be a specified thin layer by a layer regulating member 41 which press-contacts with the surface of the developer carrier 11a, the member 41 is formed of a magnetic member, so that it is attracted by a fixed magnet 11b provided in the developer carrier and press-contacts with the surface of the carrier 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a facsimile,
The present invention relates to a layer regulating device used in a developing device in an image forming apparatus that forms an image by an electrophotographic method such as a laser beam printer.

[0002]

2. Description of the Related Art A developing device using this type of layer regulating device is disclosed, for example, in Japanese Patent Publication No. 63-16736 as a developing device using a one-component developer.

These conventionally known ones use a rubber or metal flat plate having elasticity as a layer regulating blade. Specifically, the belly surface of the tip of the layer control blade,
Alternatively, the edge portion at the tip is provided so as to come into pressure contact with the surface of the developer carrying member.

In both of the so-called abdomen contact method and edge contact method, the layer regulating blade is an elastic body made of rubber or a leaf spring. The layers are pressed against each other, and the above-mentioned layer regulation is performed by this pressing force. Therefore, no special member for pressure welding is required.

[0005]

However, as described above, the pressure contact method with the developer carrying member by the abutting of the layer-regulating blade accompanied by the bending of the layer-regulating blade is different from the variation in the position for supporting the rear portion of the layer-regulating blade and the layer-regulating blade. Variations in the pressure contact force are likely to occur due to the dimensional error of, the wear during use, and the like. For this reason, the layer thickness of the developer regulated by the layer regulation blade sometimes becomes uneven in the longitudinal direction of the layer regulation blade or changes with time. Bring

In order to firmly support the rear end portion of the layer regulating blade under the same conditions, it is necessary to have a sufficient supporting structure over the entire rear portion of the layer regulating blade. For this reason, the installation space for the layer regulation blade is likely to be large including the support structure, which hinders downsizing of the device.

Therefore, an object of the present invention is to provide a layer regulating device which can solve the above problems by improving the pressure contact structure of the layer regulating member.

[0008]

In order to achieve the above object, the first invention of the present application is a layer in which a developer carried on a surface of a developer carrying member is pressed against the surface of the developer carrying member. In the layer regulation device that makes a predetermined thin layer by the regulation member,
The layer regulating member is a magnetic member, and the layer regulating member is attracted by a fixed magnet provided in the developer bearing member to be pressed against the surface of the developer bearing member.

The second invention of the present application is the same as the first invention, wherein the layer regulating member is located at a pressure contact position with the developer carrying member.
It is characterized in that it faces the magnetic pole of a magnet in the developer carrying member.

A third aspect of the invention of the present application is the feature of the second aspect of the invention, further characterized in that the layer regulating member is held so as to be capable of coming into contact with and away from the developer carrying member.

A fourth aspect of the invention of the present application is the feature of the second aspect of the invention, further characterized in that the layer regulating member is made of an elastic blade and is brought into contact with the developer carrying member with bending.

[0012]

According to the above configuration of the first invention of the present application, the layer regulating member is a magnetic member and is pressed against the surface of the developer carrying member by being attracted by the fixed magnet in the developer carrying member. The force is almost determined by the positional relationship between the layer regulating member and the fixed magnet, which is not easily affected by the dimensional error and wear of the layer regulating member. The layer regulating member only needs to be movably supported, and the mounting structure at a predetermined position is required. Since there is no particular need for it, the influence of variations in the mounting position is eliminated, and a predetermined pressure contact force is guaranteed throughout the layer regulation member, and uniform layer regulation is achieved over the entire length of the layer regulation member and over time. be able to.

According to the above configuration of the second invention of the present application,
In the invention, the layer regulation member is strongly and stably attracted to the magnetic pole of the fixed magnet in the developer bearing member at the position of pressure contact with the developer bearing member, so that it is more uniform and stable. Layer regulation can be performed.

According to the above configuration of the third invention of the present application, the first
Alternatively, in the second aspect of the invention, the layer regulating member is held so as to be separable from and in contact with the developer carrying member, and the attraction by the fixed magnet is equally received over the entire area facing the developer carrying member. A uniform and stable layer regulation can be achieved by holding the structure.

According to the above configuration of the fourth invention of the present application,
Alternatively, in the second invention, the magnetic layer regulating member is made of an elastic blade and abuts on the developer carrying member with a deflection, and the uniform and stable layer regulation by the magnetic force corresponds to the deflection of the layer regulating member. It can be performed more fully by adding resilience.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A layer regulating device as a first embodiment of the present invention shown in FIGS. 1 and 2 will be described.

FIG. 1 shows an image forming mechanism provided with the layer regulating device. This image forming mechanism uses a one-component developer, and includes a developing device casing 2 and a waste toner casing 3.
And are arranged on both sides of the photosensitive drum 4.

The photosensitive drum 4 is formed by forming a photoconductive layer such as selenium or an organic photoconductive material on the surface of a metal base such as aluminum. The surface of the photosensitive drum 4 is uniformly charged by the charging charger 5 on the upper side. An electrostatic latent image is formed by receiving image exposure as indicated at 23. This electrostatic latent image is developed by the developer supplied from the developing device casing 2 and becomes a visible image.

This visible image is transferred to 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 the 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 developing device casing 2 facing the photosensitive drum 4.
It is axially supported on the side wall of the developing device casing 2.

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

A developer supplying paddle 15 for stirring the developer in the developing device casing 2 while supplying the developer in the developing device casing 2 to the fur brush 13 is provided in the developing device casing 2, and a stirring blade 17 for preventing the toner from blocking. Is installed.

At the upper edge of the toner supply port 2a of the developing device casing 2, there is provided a layer regulating blade 41 which extends to the peripheral surface of the developing roller 11 and comes into pressure contact therewith.

The layer-regulating blade 41 serves to make the developer supplied by the fur brush 13 on the developing roller 11 into a thin layer having a predetermined thickness, and is made of a magnetic material. The magnetic material used for this may be a metallic material, but urethane rubber, silicone rubber mixed with a magnetic material, or other suitable synthetic resin may be used.

Such a layer regulating blade 41 is slidably held on the surface of the developing roller 11 by channel guides 42 fixed to both sides of the developing device casing 2 so as to be radially slidable and capable of coming into contact with the surface of the developing roller 11. Has become.

On the other hand, the developing roller 11 comprises a developing sleeve 11a which is driven to rotate to carry and convey the developer, and a fixed magnet 11b provided in the developing sleeve 11a. The fixed magnet 11b is provided on the layer regulation blade 41.
2 is sucked and brought into pressure contact with the surface of the developing sleeve 11a.
As described above, the developer carried and carried on the developing sleeve 11a is regulated to a predetermined layer thickness t. The magnetic pole S or N of the fixed magnet 11b faces the portion where the layer restriction blade 41 is in pressure contact with the developing sleeve 11a so that the fixed magnet 11b can strongly and surely attract the layer thickness regulating blade 41.

Further, the magnetic pole of the fixed magnet 11b does not have to be opposed to the portion where the layer regulating blade 41 is opposed to the developing sleeve 11a, and a magnetic force acting on the layer regulating blade 41 due to the displacement of the opposing position can be provided. .

A seal piece 25 is provided on the lower edge of the toner supply port 2a of the developing device casing 2, and the developing roller 11
It extends upward and is in pressure contact. The seal piece 25 is made of polyethylene terephthalate (PET) or the like, and allows the residual toner after being carried on the developing roller 11 and subjected to development on the photosensitive drum 4 to pass through the toner supply port 2a, but the toner supply port Preventing the developer from coming off from 2a.

According to the experiments conducted by the present inventor, the layer regulating blade 41 is held by the channel guides 42 on both sides so as to be movable up and down and guided by the magnetic force from the magnetic pole S of the fixed magnet 11b. It was strongly sucked and sufficiently and stably pressed against the surface of the developing sleeve 11a.

However, this pressure contact force is variously set according to the type of developer and the size of the layer thickness t determined according to other developing conditions. Such pressure contact force can be set freely depending on the magnetic force of the fixed magnet 11b, the type and size of the magnetic body, and the like.

When the magnetic material forming the layer regulating blade 41 is rubber or synthetic resin material mixed with a magnetic material, the pressure contact force can be set by changing the mixing ratio of the magnetic material. Further, the pressure contact force can be changed depending on the thickness of the nonmagnetic material.

The layer regulating blade 41 is easily worn when it is made of rubber or synthetic resin. However, the wear does not affect the pressure contact force due to the attraction of the fixed magnet 11b.

Moreover, the attraction force of the fixed magnet 11b is evenly distributed over the entire area of the layer-regulating blade 41 abutting on the surface of the developing sleeve 11a and does not fluctuate. As a result, a uniform pressure contact force was obtained over the entire contact area without fluctuation over time.

In this sense, the holding of the layer regulating blade 41 is
The better it is, the more rough it is so that it does not vibrate or fall off.
The support structure is simplified. Further, when the layer regulating blade 41 is worn, the layer regulating blade 41 slides against the surface of the developing sleeve 11a, which is convenient for obtaining a uniform pressure contact force.

The layer-regulating blade 41 may have a shape other than the blade type, and the shape and the holding structure may be freely selected as long as they are in close contact with the surface of the developing sleeve 11a. It can also be supported at the tip of a rotatable lever member.

The developing sleeve 11a is preferably non-magnetic, but the developer may be non-magnetic or magnetic. It does not matter whether or not the toner layer contacts the photosensitive drum 4.

Toner recovery port 3a of the waste toner casing 3
A cleaning blade 7 extending to the surface of the photosensitive drum 4 is provided at the upper edge of the photosensitive drum 4, and removes residual toner adhering to the surface of the photosensitive drum 4 after transfer. The removed toner is scraped into the inside of the waste toner casing 3 by the paddle 8.

The photosensitive drum 4 is provided at the lower edge of the toner recovery port 3a.
A seal piece 26 extending to the surface of the cleaning blade 7 is provided to allow the residual toner after the transfer on the surface of the photosensitive drum 4 to pass to the cleaning blade 7 side.
Thus, the toner removed from the surface of the photosensitive drum 4 is prevented from passing through to the transfer portion side and leaking.

FIG. 3 shows a second embodiment of the present invention in which a magnetic material made of an elastic material such as rubber or synthetic resin mixed with a magnetic material is used as the layer regulating blade 51.

The layer regulating blade 51 is a supporting member 52 fixed along the upper edge of the toner supply port of the developing casing 2.
The rear end portion is attached by adhesion or the like, and the front end portion is brought into pressure contact with the surface of the developing sleeve 11a with the entire bending.

Therefore, the tip of the layer-regulating blade 51 is pressed against the surface of the developing sleeve 11a by the attraction force of the fixed magnet 11b in the developing sleeve 11a and the elastic restoring force of the layer-regulating blade 51. It is suitable for obtaining a stable force.

[0042]

According to the first aspect of the present invention, the layer regulating member is a magnetic member, and when it is attracted by the fixed magnet in the developer carrying member, it is pressed against the surface of the developer carrying member. Is almost determined by the positional relationship between the layer regulation member and the fixed magnet, and this is not easily affected by dimensional errors and wear of the layer regulation member, and the layer regulation member only needs to be movably supported, and the mounting structure at a predetermined position Is not required, the influence of variations in the mounting position is eliminated, and the prescribed pressure contact force is guaranteed at all times and in the entire layer regulation member, and even layer regulation is achieved over the entire length of the layer regulation member and over time. Therefore, it is possible to ensure highly accurate development characteristics with a simple and compact pressure contact structure.

According to the second invention of the present application, further, in the first invention, the layer regulating member strongly opposes the magnetic pole of the fixed magnet in the developer carrying body at the position of pressure contact with the developer carrying body, Further, since the ink is sucked in stably and the layer regulation is further uniform and stable, the developing characteristics can be further stabilized.

According to the third invention of the present application, the first or second
Further, in the invention, the layer regulating member is held so as to be able to come into contact with and separate from the developer carrying member, and is equally attracted by the fixed magnet over the entire area facing the developer carrying member, and is held by a simple guide structure. Thus, uniform and stable layer regulation can be achieved, and simplification of the structure and miniaturization can be further promoted without affecting development characteristics.

According to the fourth aspect of the present invention, the first or second aspect
Further, in the invention, the layer regulating member is made of an elastic blade and is abutted on the developer carrying member with bending, and the uniform and stable layer regulation by magnetic force is also applied with the restoring force of the bending amount of the layer regulating member. Further, since it can be sufficiently performed, it is possible to sufficiently cope with the case where strong, uniform and stable layer regulation is required.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an image forming mechanism using a layer regulating device according to an embodiment of the present invention.

FIG. 2 is a side view showing a layer regulation state by the layer regulation blade of FIG.

FIG. 3 is a side view of a layer regulating device showing a second embodiment of the present invention.

[Explanation of symbols]

 11 developing roller 11a developing sleeve 11b fixed magnets 41, 51 layer regulation blade 42 guide 52 supporting member

Claims (4)

[Claims] 1. A layer regulation device for forming a predetermined thin layer by a layer regulation member that presses a developer carried on a surface of a developer carrier and is conveyed to the surface of the developer carrier, wherein the layer regulation member is a magnetic member. The layer regulation device is characterized in that the layer regulation member is attracted by a fixed magnet provided in the developer bearing body and brought into pressure contact with the surface of the developer bearing body. 2. The layer regulating device according to claim 1, wherein the layer regulating member faces a magnetic pole of a magnet in the developer bearing body at a position where the layer regulating member is pressed against the developer bearing body. 3. The layer regulating device according to claim 1, wherein the layer regulating member is held so as to be capable of coming into contact with and away from the developer carrying member. 4. The layer-regulating device according to claim 1, wherein the layer-regulating member is made of an elastic blade and is in contact with the developer carrying member while flexing.