JPH0256579A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an excellent image of uniform image density having no 'sweep trace' by installing a magnet body opposite to a developing sleeve and also installing a magnet body which is sandwiched between magnets with the same polarity at a position opposite a photosensitive body in the developing sleeve. CONSTITUTION:The developing sleeve 2 which is made of a rotatable nonmagnetic body is installed opposite the photosensitive drum 1, a nap cutting plate 3 facing the developing sleeve 2 and a rotatable agitation blade above the developing sleeve 2 are installed, and plural conveying magnetic poles 6 are installed in the developing sleeve 2 so that the opposite polarities adjoin to each other. The magnet body 7 is installed between conveying magnetic poles with the same polarity opposite the photosensitive body and a magnet body 8 is provided in the photosensitive drum opposite the developing sleeve. A layer of a developer formed in the rotating direction of the developing sleeve is disordered in the axial direction of the developing sleeve through the operation of the magnet body in the developing sleeve and the magnet body in the photosensitive drum to form the uniform layer of the developer on the developing sleeve.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an image forming apparatus that uses a magnetic developer to visualize an electrostatic latent image.

(Prior Art) Generally, in an electrophotographic apparatus, a developing device containing a powder developer is installed in a part of the outer periphery of the photoreceptor drum, and the developer is attached to the electrostatic latent image formed on the photoreceptor drum. It is visualized by doing this. There are two types of developer: magnetic developer and non-magnetic developer. In a developing device that uses magnetic developer, the developer is placed on a developing sleeve made of a rotatable non-magnetic plate, and is installed inside this developing sleeve. The electrostatic latent image on the photoreceptor is visualized by magnetizing the developer with the magnetic poles and forming a magnetic brush.

In such a developing device, the rotation of the developing sleeve causes
The developer magnetized on the developing sleeve moves in the rotational direction of the developing sleeve and is conveyed to a position facing the photoreceptor.

However, in such an image forming apparatus, a layer of developer is formed in the rotational direction of the developing sleeve of the developing device, and a uniform layer of developer cannot be formed. For this reason, when an image is formed, there are problems such as streaks called "cross-cuts" are formed on the image, and the image density is not uniform.

(Problems to be Solved by the Invention) As detailed above, in a developing device using a magnetic developer, a layer of developer is formed in the rotational direction of the developing sleeve.
This resulted in problems such as sushi spots called "hakime" appearing on the image and uneven image density.

In the present invention, in order to solve the above problems, by forming a uniform layer of developer on the developing sleeve,
The objective was to obtain a good image with uniform developed density without any problems.

(Means for Solving the Problems) In the present invention, in order to solve the above problems, a magnetic body is installed at a position facing the developing sleeve inside the electrostatic latent image support,
By installing a magnetic material sandwiched between magnets of the same polarity inside the developing sleeve at a position facing the photoreceptor, the layer of developer formed in the rotational direction on the developing sleeve is disturbed in the axial direction of the developing sleeve. A uniform developer layer was formed.

(Function) Due to the action of the magnetic material in the developing sleeve and the magnetic material in the photoreceptor drum, the layer of developer formed in the rotational direction of the developing sleeve is disturbed in the axial direction of the developing sleeve, so that the layer of developer formed on the developing sleeve is A uniform layer of developer is formed on the surface. For this reason,
A good image with uniform image density and no blemishes can be obtained.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings.

First, the O-position structure used in this embodiment will be explained with reference to FIG. Reference numeral 1 in FIG. 1 is a photosensitive drum, on which an electrostatic latent image is formed. A rotatable developing sleeve 2 made of a non-magnetic material is installed at a position facing the photosensitive drum 1, a cutting plate 3 is placed at a position in contact with the developing sleeve 2, and a rotatable stirring blade 4 is placed above the developing sleeve 2. is installed. Further, inside the developing sleeve 2, a plurality of transport magnetic poles 6 were installed so that opposite magnetic poles were placed next to each other, and a magnetic body 7 was installed between the transport magnetic poles of the same polarity at a position facing the photoreceptor. . Further, a magnetic body 8 is provided in the photosensitive drum at a position facing the developing sleeve. FIG. 2 shows a structural diagram of this magnetic material. The magnetic body 8 vibrates around the shaft 9 as the photosensitive drum 1 rotates.

Next, the operation of this image forming apparatus in the developing process will be explained. The developer conveyed onto the developing sleeve 2 by the stirring blade 4 is magnetized by an internal conveying magnetic pole on the developing sleeve 2 to form a layer of developer. As the developing sleeve 2 rotates, the developer is transported to a position facing the photoreceptor.
The electrostatic latent image that is transferred onto the photosensitive drum 1 and formed on the drum 1 is visualized. Here, since the magnetic body installed inside the photoconductor drum vibrates as the photoconductor drum rotates around the shaft 9, the vibration of the magnetic body 9 causes the magnetic body installed inside the developing sleeve to vibrate. 7 vibrates. The vibration of the magnetic body 7 disturbs the developer layer formed in the direction of rotation of the developing sleeve, forming a uniform developer layer. As a result, when an image is formed, a good image with uniform image density and no "cross-cuts" can be obtained.

〔Effect of the invention〕

As detailed above, according to the present invention, the developer layer is disturbed by the action of the developing magnetic pole to form a uniform developer layer.
A good, uniform image with a degree of image quality and no "blind marks" can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the developing device of the present invention, and FIG.
FIG. 3 is a schematic diagram showing the structure of a magnetic body installed within a photoconductor in one embodiment of the present invention. 6...Transporting magnetic pole 7...Magnetic material 8...Magnetic material agent Patent attorney Noriyuki Chika Same as above Diagram Yamashita

Claims (1)

[Claims] In an image forming apparatus that forms a magnetic brush of developer and visualizes the electrostatic latent image by rubbing the magnetic brush against an electrostatic latent image support, the image forming apparatus includes a collecting section that collects the developer; a rotatably provided cylindrical non-magnetic plate; magnets having sequentially opposite polarities along the inner circumferential surface of the non-magnetic plate; and the non-magnetic plate on the circumferential surface of the electrostatic latent image support. An image forming apparatus characterized in that magnetic bodies are provided at opposing positions.