JPH04100076A - developing device - Google Patents

Abstract

PURPOSE:To easily remove developer by a removing means by arranging a shielding member which always shields a magnetic field from a magnetic field generating means at the inside part of the surface part of a developer carrying means on which the removing means abuts. CONSTITUTION:In order to prevent the ghost of a developing sleeve, residual magnetic toner 1 on the surface of the developing sleeve 32 is removed by a scraper 38 which abuts on the sleeve 32 on a downstream side in a developing area after development. Since a magnetic material 40 is provided inside the sleeve 32 and at a position where the scraper 38 abuts, the magnetic field from a magnetic roll 34 mostly passes inside the magnetic material 40 and hardly goes to the outside of the sleeve 32 at such a time. As a result, the attractive force of the sleeve 32 and the toner 2 at the position on the sleeve 32 where the scraper 38 abuts becomes weak and the toner 1 is easily removed from the sleeve 32 at this position with small force. Therefore, the abutting force of the scraper 38 for removing the toner 1 is made small and the thawing of the pressure of the toner 1 is prevented. Thus, a beautiful image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device installed in an electrophotographic device or the like that develops an electrostatic latent image on a photoreceptor into a visible image.

[Prior Art] Conventionally, as a developing device for developing an electrostatic latent image recorded on a photoreceptor into a visible image using a magnetic developer, a second developing device is used.
A configuration as shown in the figure is being considered. FIG. 2 shows a conventional example of a developing device using a one-component developing method using magnetic toner.

The configuration of this developing device 10 will be described below with reference to FIG.

The developing device 10 is roughly divided into a storage section 20 that stores the magnetic toner 1, and a storage section 20 that is provided below the storage section 20, and a photoreceptor 10.
The developing section 30 develops the electrostatic latent image of the image recorded on the surface of the 0. Further, the housing section 20 and the developing section 30 form one housing 12.

The storage section 20 includes a storage container 22 in which the magnetic toner 1 is stored, and an opening 2 provided below the storage container 22.
4 and a toner replenishing roller 26 provided at the toner replenishing roller 26.

At the center of the developing section 30, a developing section 30 is provided with magnetic toner 1 replenished by a toner replenishing roller 26 on its surface, and is rotated by a driving means (not shown), facing a photoreceptor 100 carrying an electrostatic latent image. magnetic toner to the area 1
A non-magnetic developing sleeve 32 for conveying the image is provided. Inside the developing sleeve 32, a magnet roll 34, which is a magnetic field generating means for supporting the magnetic toner 1 on the surface of the developing sleeve 32, is provided so as to be rotatable relative to the developing sleeve 32. A layer thickness regulating blade 36 is fixed to the housing 12 above the developing sleeve 32 in order to regulate the layer thickness of the magnetic torch 1 supported on the surface of the developing sleeve 32.

Furthermore, a scraper 38 is provided so as to come into contact with the surface of the developing sleeve 32 on the downstream side of the developing area, for removing the magnetic toner 1 remaining on the surface of the developing sleeve 32 even after development. .

The magnetic toner 1 in the storage container 22 is transferred to the toner replenishing roller 2.
The developing sleeve 32 is discharged by the rotation of the developing sleeve 32, and is attached by the magnetic force of the magnet roll 34 disposed inside the developing sleeve 32. The developing sleeve 32 and the magnet roll 34 are rotatably supported relative to each other, and the magnetic toner 1 forming a magnetic brush on the developing sleeve 32 is repeatedly transferred and developed by the rotation of the developing sleeve 32 and the magnet roll 34. sleeve 3
2 and is triboelectrically charged. The thus charged magnetic toner 1 has its spike height regulated by the layer thickness regulating blade 36, and is transported to the developing area where it is placed on the photoreceptor drum 10.
It adheres to the electrostatic latent image on 0 with electrostatic force and develops into a visible image. After development, the magnetic toner 1 remaining on the developing sleeve 32 is
It is scraped off by a scraper 38 that is pressed against the developing sleeve 32 downstream of the developing area. This is to prevent so-called sleeve ghost, where the effects of previous development appear again.

[Problems to be Solved by the Invention] However, in the developing device 10 having the above configuration,
The magnetic toner 32 and the developing sleeve 40 are a magnet roll 42.
Since it is strongly attached by the magnetic force of the developing sleeve 40, the scraper 46 must be pressed against the developing sleeve 40 with strong force in order to scrape it off.

Therefore, the magnetic toner 32 may fuse due to pressure at the contact position with the developing sleeve 40, causing toner clogging, or the magnetic toner 32 may adhere to the developing sleeve 40, causing the magnetic toner 1 on the developing sleeve 40 to The layer becomes non-uniform, and as a result, a good image cannot be obtained.

Furthermore, in order to prevent this phenomenon, it is possible to reduce the magnetic force of the magnet roll 42 and the magnitude of the saturation magnetization of the magnetic toner 32, but this will weaken the adhesion force of the magnetic toner 32 to the developing sleeve 40 and cause the toner to scatter. This is undesirable because it causes the inside of the device and the top of the photoreceptor drum 38 to become dirty.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a developing device that can easily remove the developer on the developer conveying means.

[Means for Solving the Problems] In order to achieve the above object, the developing device of the present invention includes a photoconductor on which an electrostatic latent image of an image is recorded, a developer having magnetic properties, and a developer having magnetic properties. A developer is carried on the surface of the electrostatic latent image and conveyed to a development area facing the photoconductor, and the developer is attached to the electrostatic latent image to develop the image. a cylindrical developer transporting means comprising a cylindrical developer transporting means; and a developer transporting means fixedly arranged so as to be in contact with the surface of the developer transporting means, and remaining on the surface of the developer transporting means after passing through the development area. a removing means for removing the developer, and a shielding member for shielding the magnetic field from the magnetic field generating means is fixedly disposed on an inner part of the surface portion of the developer conveying means that the removing means is in contact with. has been done.

[Function] According to the present invention having the above configuration, the magnetic developer remaining on the developer transport means after passing through the development area is removed from the position where the shielding member is provided inside the developer transport means. At this point, the magnetic adsorption force between the developer and the conveying means is weakened, making it easier for them to separate from each other.

At that time, the removing means removes the developer from the developer transport means.

[Example 1] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

First, the configuration of the developing device of this embodiment will be explained with reference to FIG. FIG. 1 is a schematic diagram of a developing device.

The developing device 10 is roughly divided into a storage section 20 that stores the magnetic toner 1, and a storage section 20 that is provided below the storage section 20, and a photoreceptor 10.
The developing section 30 develops the electrostatic latent image of the image recorded on the surface of the 0. Further, the housing section 20 and the developing section 30 form one housing 12.

The storage section 20 includes a storage container 22 in which the magnetic toner 1 is stored, and an opening 2 provided below the storage container 22.
4 and a toner replenishing roller 26 provided at the toner replenishing roller 26.

At the center of the developing section 30, a developing section 30 is provided with magnetic toner 1 replenished by a toner replenishing roller 26 on its surface, and is rotated by a driving means (not shown), facing a photoreceptor 100 carrying an electrostatic latent image. magnetic toner to the area 1
A non-magnetic developing sleeve 32 for conveying the image is provided. Inside the developing sleeve 32, a magnet roll 34, which is a magnetic field generating means for supporting the magnetic toner 1 on the surface of the developing sleeve 32, is provided so as to be rotatable relative to the developing sleeve 32. Above the developing sleeve 32, a layer thickness regulating blade 36 for regulating the layer thickness of the magnetic toner 1 carried on the surface of the developing sleeve 32 is mounted on the housing 12.
It is fixedly installed. Furthermore, a scraper 38 is provided so as to come into contact with the surface of the developing sleeve 32 on the downstream side of the developing area, for removing the magnetic toner 1 remaining on the surface of the developing sleeve 32 even after development. . Further, a magnetic body 40 is provided inside the developing sleeve 32 at a position where the scraper 38 contacts. The magnetic body 40 is made of a material with high magnetic permeability, such as ferrite, and its position is fixed regardless of the rotation of the developing sleeve 32.

Here, the magnetic toner 1 is a powder containing 10% to 65% of magnetic powder such as ferrite in a styrene-acrylic resin, and has an average particle size of about 10 μm (micrometers) mixed with carbon black as a colorant. Positively charged toners use electron-donating substances such as nigrosine dyes, fatty acid metal salts, and quaternary ammonium salts, while negatively charged toners use electron-accepting substances such as azo metal-containing dyes, chlorparaffins, and chlorinated polyesters. Substances are added externally.

Further, the surface of the developing sleeve 32 is desirably coated with a substance that charges the magnetic toner 1 to a predetermined polarity. Silicon or the like is preferable for charging.

Next, the operation of the developing device 10 of this embodiment will be explained with reference to FIG.

The magnetic toner 1 in the storage container 22 is transferred to the toner replenishing roller 2.
6 is discharged, and is attached to the surface of the developing sleeve 32 by the magnetic force of the magnet roll 34 provided inside the developing sleeve 32. The developing sleeve 32 and the magnet roll 34 are relatively rotatably supported, and the magnetic toner 1 forming a magnetic brush on the developing sleeve 32 is
As the developing sleeve 32 and the magnet roll 34 rotate, the magnet is repeatedly transferred and charged by friction between the developing sleeve 32 and the developing sleeve 32 . The thus charged magnetic toner 1 has its spike height regulated by the layer thickness regulation blade 36, and is transported to the development area where an electrostatic latent image is applied to the electrostatic latent image recorded on the surface of the photoreceptor 100. It is attached to the film and developed into a visible image. After development, the magnetic toner 1 remaining on the surface of the developing sleeve 32 is removed by a scraper 38 that is in contact with the developing sleeve 32 downstream of the developing area.
removed by This is to prevent so-called developing sleeve ghost, where the effects of previous development appear again. At this time, as described above, since the magnetic body 40 is provided inside the developing sleeve 32 at the contact position of the scraper 38, most of the magnetic field from the magnet roll 34 passes through the inside of the magnetic body 4o, It rarely appears outside. As a result, the adhesion force between the developing sleeve 32 and the magnetic toner 1 at the position on the developing sleeve 32 where the scraper 38 contacts is weakened, and the magnetic toner 1 cannot be removed from the developing sleeve 32 with a weak force at this position. can. Therefore, the contact force of the scraper 38 provided for removing the magnetic toner 1 can be weakened, so it is possible to prevent pressure melting of the magnetic torch 1 at this position, and as a result, a beautiful image can be obtained. A developing device can be provided.

Further, the present invention is not limited to the examples detailed above, and changes can be made without departing from the spirit thereof.

For example, the storage section 20 and the developing section 30 may not be configured in the same housing.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, the magnetic field from the magnetic field generating means is always applied to the inner part of the surface of the developer conveying means that the removing means is in contact with. Since the shielding member for shielding is disposed, it is possible to provide a developing device in which the removing means can easily remove the developer, which is an industrially advantageous effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a developing device according to the present invention, and FIG. 2 is a schematic diagram of a conventional developing device. In the figure, 1 is a magnetic toner, 10 is a developing device, 12 is a housing, 32 is a developing sleeve, 34 is a magnet roll, 36 is a layer thickness regulating blade, 38 is a scraper, and 40 is a magnetic material.

Claims (1)

[Scope of Claims] 1. A photoreceptor on whose surface an electrostatic latent image of an image is recorded, a magnetic developer, and a photoreceptor with the developer supported on its surface facing the photoreceptor. A cylindrical developer conveying means that conveys the developer to a development area and causes the electrostatic latent image to be visualized and developed by adhering the developer to the electrostatic latent image, and is provided with a magnetic field generating means therein; a developing device that is fixedly disposed so as to come into contact with the surface of the conveying means, and removes developer remaining on the surface of the developer conveying means after passing through the developing area; A developing device characterized in that a shielding member for shielding the magnetic field from the magnetic field generating means is disposed inside a portion of the surface of the developer conveying means that the means is in contact with.