JPH026982A - Developing device - Google Patents

Abstract

PURPOSE:To prevent toner from flying out by providing non-magnetic material for recovering developer at a location facing the developing downstream area of a carrier roller and between a receiving member for magnetic developer such as toner falling from the carrier roll and the carrier roll itself. CONSTITUTION:The non-magnetic member 16 for recovering developer is provided at the location facing the developing downstream of the carrier roll 1, and between the receiving member 2 receiving the magnetic developer such as toner falling from the carrier roller 1 and the carrier roll 1. Even if a magnet 3 is rotated, the magnetic developer moving in the direction opposite to its original carrying direction moves along the non-magnetic member 16 due to its revolution. As a result, even if the magnetic roll 3 is rotated to develop an image sharply, the magnetic developer never moves outside a storing vessel 4. The magnetic developer can thereby be prevented from flying out.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is used in an electrostatic recording device such as an electronic copying machine, for example, to record an electrostatic latent image formed on the photosensitive surface of a photoreceptor. The present invention relates to a developing device for developing.

(Prior art) An electrostatic latent image is formed on the photosensitive surface of a photosensitive drum by carrying a developer on a carrier roll by magnetic force and bringing the developer carried on the carrier roll into contact with a photosensitive drum. In developing devices that develop images, various methods have been considered for bringing toner into contact with a photoreceptor drum.
The figure is a cross-sectional configuration diagram showing an example of a developing device using a method capable of performing clear development.

In the figure, 1 is a photosensitive drum, and a sleeve 2 as a carrier roll is provided parallel to this. Inside the sleeve 2 is provided a magnet roll 3 in which a plurality of magnetic poles are alternately arranged. Under the action of the magnetic roll 3 , toner 5 as a magnetic developer stored inside the storage container 4 is supported on the outer peripheral surface of the sleeve 2 .

Note that the bottom portion 4a of the storage container 4 serves as a receiving member that receives the toner 5 that has fallen from the sleeve 2.

6 is a blade, and when the sleeve 2 is rotated,
The (toner layer thickness) of the toner 5 carried by the sleeve 2 and moved as it rotates and guided to the outside of the storage container 4 is kept constant.

Note that 7 to 9 and 11 to 13 are well-known devices that constitute an electrostatic recording device together with this developing device; 7 is a charging unit that charges the photoreceptor drum 1; 8 is a charging unit that exposes the photoreceptor drum 1 to static electricity; An exposure section 9 forms an electrostatic latent image, a transfer section 9 transfers the toner 5 attached to the electrostatic latent image formed on the photoreceptor drum 1 by this developing device onto the recording paper 10, and a transfer section 11 transfers the toner from the photoreceptor drum 1 to the recording paper. The peeling part that peels off 10, 12 has been transferred to the recording paper 10! - A fixing section 13 is a cleaning section that cleans the photoreceptor drum 1;

Further, 14a and 14b are recording paper guides, and 15a and 15b are conveyance rollers.

In the developing device configured as described above, the photosensitive drum 1 is rotated in the direction of arrow A in the figure, and the sleeve 2 is rotated in the direction of arrow B in the figure in opposition to this. Then, move the magnetic roll 3 in the opposite direction to the sleeve 2 by arrow C in the figure.
The toner 5 carried on the sleeve 2 is brought into contact with the photoreceptor drum 1. The l/toner 5 that has come into contact with the photosensitive drum 1 in this manner adheres to the portions where the electrostatic latent image is formed on the photosensitive surface due to the electric charges of the electrostatic latent image. Further, the toner 5 that has come into contact with the portion where the electrostatic latent image is not formed is continuously conveyed as the sleeve 2 rotates, and is stored into the storage container 4 from the lower part of the sleeve 2.

However, in the conventional developing device described above, the following problem occurs when the toner 5 that has not adhered to the photoreceptor drum 1 is stored in the storage container 4.

FIG. 4 is an enlarged sectional view schematically showing the vicinity of the lower part of the sleeve 2. As shown in FIG. As shown in the figure, the toner 5 that has not adhered to the photoreceptor drum is carried between the sleeve 2 and the storage container bottom 4a and stored in the storage container 4 while being held in the sleeve 2. be done. By the way, at this time,
The sleeve 2 and the magnet roll 3 are rotating in opposite directions (in the figure, the sleeve 2 is rotating counterclockwise and the magnet roll 3 is rotating clockwise), and the magnetic field applied to the toner 5 is constantly changing. It rotates counterclockwise due to the influence of magnetic field changes. Therefore, when the toner 5 located on the outer periphery of the toner layer carried by the sleeve 2 comes into contact with the storage container bottom 4a, the toner 5 moves in the opposite direction to the conveyance direction shown in the figure due to the rotation, and further It moves along the wall of the storage container 4 as shown by arrow E in the figure. The magnetic force of the magnet roll 3 is weak outside the wall of the storage container 4, and the toner 5 that has moved to the outside of the wall of the storage container may be scattered.

The above problem occurs because the magnet roll 3 rotates in the direction of arrow C in the figure, which is opposite to the sleeve 2, so if the magnet roll 3 is rotated in the same direction as the sleeve 2, this problem will not occur. However, when the magnet roll 3 is rotated in the direction of arrow B in the figure, the distance between the photosensitive drum 1 and the sleeve 2 is slightly smaller than the toner layer thickness, so the developing area is As shown in FIG. 5, the toner 5a accumulated in the flow section moves in the direction of arrow F in the figure due to rotation, resulting in circulation as shown.

As a result, the adhesion of the toner 5 to the photoreceptor drum becomes inappropriate, resulting in the quality of the image obtained being inferior to that of the developing device shown in FIG.

(Problems to be Solved by the Invention) As mentioned above, in the conventional developing device, in order to perform the phenomenon clearly, the sleeve is rotated so that the toner is conveyed from the upper side of the sleeve, and the magnetic roll is separate from the sleeve. Since it is rotated in the opposite direction, when toner that is not attached to the photoreceptor drum is stored in the storage container, some of the toner moves to the outside of the storage container and scatters, causing damage to the inside of the electrostatic recording device and the like. There was a problem with the recording paper becoming obsolete. Furthermore, if the rotation direction of the magnetic roll is reversed to prevent toner from scattering, the quality of the resulting image will deteriorate.

Therefore, the present invention prevents deterioration of image quality,
An object of the present invention is to provide a developing device that can prevent l-ner from scattering.

[Structure of the Invention] (Means for Solving the Problems) The present invention comprises a magnetic roll formed by alternately arranging a plurality of magnetic poles and rotating in a predetermined direction, and this magnetic roll inside, A magnetic developer such as toner carried on the carrier roll rotated in a direction opposite to the predetermined direction is brought into contact with the photoreceptor drum, and an electrostatic latent image formed on the photoreceptor drum is developed. In the developing device, a magnetic developer such as toner, which is disposed at a position facing the downstream side of the carrier roll and falls from the carrier roll, is located between the receiving member and the carrier roll. A non-magnetic member for developer recovery was provided at the position.

(Function) By taking such a measure, even if the magnet body 3 is rotated as shown in the first figure, the magnetic developer that moves in the opposite direction to the original feeding direction due to its rotation will be moved by the provided non-magnetic developer. Move along the magnetic member.

Therefore, even if the magnetic roll is rotated so that clear development can be performed, the magnetic developer does not move to the outside of the storage container, and the magnetic developer does not scatter.

(Example) Hereinafter, a developing device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the configuration of the developing device.

Note that the same parts as in FIG. 3 are given the same reference numerals, and detailed explanation thereof will be omitted.

Here, the feature of this developing device is that the sleeve 2
A non-magnetic plate member 15 is provided between the storage container bottom 4a and the storage container bottom 4a. This plate member 16 has an arcuate cross section and is provided in parallel to the sleeve 2 and the storage container bottom 4a.

However, if the developing device is configured as described above,
As shown in FIG.
6 in the opposite direction to the original conveyance direction, and further moves as shown by arrow ♀ in the figure. Therefore, the toner 5 that moves due to rotation also moves into the storage container 4, and all of the toner 5 is collected into the storage container 4.

As described above, according to this embodiment, even if the sleeve 2 and the magnet 3 are rotated in a direction that allows clear development, the toner 5 that moves due to its rotation moves along the plate member ]b, so that the storage container The toner 5 moves into the inside of the storage container 4 and does not move to the outside of the storage container 4, and the toner 5 does not scatter.

Note that the present invention is not limited to the 1-thick layer side. For example, in the embodiment described in -1x, a plate member was used as the non-magnetic member, but a non-magnetic film or the like may be provided. Further, the receiving member may be separate from the storage container. In addition, various modifications can be made without departing from the spirit of the present invention.

[Effects of the Invention] According to the present invention, a magnet roll is formed by alternately arranging a plurality of magnetic poles and rotates in a predetermined direction; In a developing device that develops an electrostatic latent image formed on the photoreceptor drum by bringing a magnetic developer, such as toner, carried on the carrier roll rotated in a direction into contact with a photoreceptor drum, the carrier roll A non-magnetic member for collecting the developer is provided at an intermediate position between the carrier roll and a receiving member that is provided at a position facing the downstream area of the roll to catch magnetic developer such as toner falling from the carrier roll. Since the member is provided, the developing device does not cause deterioration in image quality and can prevent toner from scattering.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining a developing device according to an embodiment of the present invention, FIG. 1 is a cross-sectional view showing the configuration of the developing device, and FIG. 2 is a diagram of the sleeve in FIG. A diagram schematically showing an enlarged view of the lower part and FIGS. 3 to 5 are diagrams each illustrating the conventional technology. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 2... Sleeve, 3... Magnet roll, 4... Storage container, 4a... Bottom of storage container, 5... Toner 16... Plate member. ] Figure Figure Figure 4 Figure 3 Figure 5

Claims (1)

[Claims] A magnet roll formed by alternately arranging a plurality of magnetic poles and rotating in a predetermined direction, and a magnet roll inside the magnet roll, which is rotated in a direction opposite to the predetermined direction. , a carrier roll carrying a magnetic developer on its outer peripheral surface, the magnetic developer carried on the carrier roll is brought into contact with a photoreceptor drum, and the electrostatic latent image formed on the photoreceptor drum is In a developing device that develops a magnetic developer, an intermediate position between the carrier roll and a receiving member that is provided at a position opposite to the development downstream area of the carrier roll and catches the magnetic developer falling from the carrier roll. A developing device characterized in that a non-magnetic member for collecting developer is provided.