JPH0744022A - Developing device for electrophotographic device - Google Patents

Abstract

PURPOSE:To stably transfer developer to plural magnetic rolls for developing by supplying the developer scooped by a magnetic roll for carrying to the magnetic roll for developing through a magnetic roll for transferring developer. CONSTITUTION:The developer 8 attracted to the magnetic roll for carrying 2 is scooped up to the side of the magnetic roll for developing 3 by the rotation of the roll 2, and adjusted to a developer layer having fixed thickness by a developer layer thickness regulating member 9. An electrostatic latent image formed on the surface of an electrostatic image holding body 10 is developed by a magnetic brush formed on the magnetic rolls for developing 3 and 4 while it is moved from the roll 3 to the roll 4. Meanwhile, the developer which can not pass through a gap between the surface of the roll 3 and the tip of the regulating member 9 is attracted to the magnetic roll for transferring the developer 7 and adjusted to the developer layer having the fixed thickness by a developer layer thickness regulating member 11, then carried to the side of the magnetic roll for developing 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an electrophotographic apparatus.

[0002]

2. Description of the Related Art In a developing device of an electrophotographic apparatus, as a method of supplying a developer to a developing magnetic roll, two developing magnetic rolls having different rotating directions are provided so as to face the surface of an electrostatic image carrier, The developer drawn up by the transporting magnetic roll provided below the developing magnetic roll is used for the above-mentioned 2
There is a so-called center feed system in which the magnetic particles are distributed and supplied to one developing magnetic roll, and this structure is known, for example, from Japanese Patent Publication No. 62-45552.

[0003]

By the way, in the case of the developing device using the above-mentioned supply system, if the magnetic roll for conveyance and the magnetic roll for development are provided at positions that are too far apart from each other,
There is a problem that the magnetic action between the two becomes weak and the delivery of the developer from the transport magnetic roll to the developing magnetic roll becomes unstable.

An object of the present invention is to provide a developing device capable of stably delivering a developer to a plurality of developing magnetic rolls.

[0005]

In order to achieve the above object, in a developing device of an electrophotographic apparatus of the present invention, a developer is transferred between at least one developing magnetic roll and the carrying magnetic roll. A magnetic roll was provided, and the developer drawn up by the carrying magnetic roll was supplied to the developing magnetic roll via the developer delivering magnetic roll.

[0006]

According to the developing device of the electrophotographic apparatus constructed as described above, it is possible to stably deliver the developer to the plurality of developing magnetic rolls.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 1 denotes a housing of a developing device. Inside the housing 1, a carrying magnetic roll 2 is provided at the bottom, and above the carrying magnetic roll 2, the developing magnetic rolls 3, 4, 5 are provided. , 6 and magnetic roll 7 for delivering developer
Is provided. A magnetic roll 2 for transportation is provided inside the housing 1.
The developer 8 is stored to such an extent that it is dipped, and the developer 8 adsorbed on the transport magnetic roll 2 is pumped up to the developing magnetic roll 3 side by the rotation of the transport magnetic roll 2.
A developing layer having a constant thickness is adjusted by the developing layer thickness regulating member 9, and the developing magnetic roll 3 to the developing magnetic roll 4 are used.
The electrostatic latent image formed on the surface of the electrostatic image holder 10 is developed by the magnetic brush formed on the developing magnetic rolls 3 and 4 while being transferred to. On the other hand, the developer that could not pass through the gap between the surface of the developing magnetic roll 3 and the tip of the developing layer thickness regulating member 9 is adsorbed by the developer delivering magnetic roll 7, and the developing layer thickness regulating member 11 keeps a constant thickness. After being adjusted to the developing layer that it has, it is conveyed to the developing magnetic roll 5 side. The transported developer is further used for the developing layer thickness regulating member 1
The surface of the electrostatic image holding member 10 is adjusted by a magnetic brush formed on the developing magnetic rolls 5 and 6 while being transferred from the developing magnetic roll 5 to the developing magnetic roll 6 while being adjusted to a developing layer having a constant thickness by 2. The electrostatic latent image formed on is developed.

In this embodiment, the peripheral speed of the developer delivering magnetic roll 7 is equal to the peripheral speed of the developing magnetic roll 5 and equal to or less than the peripheral speed of the developing magnetic roll 3. Set to do.

The developing layer thickness regulating members 9 and 12 are provided on the holding member 13 so that the gap can be adjusted independently of the developing magnetic rolls 3 and 5, respectively.

[0010]

As described above, according to the present invention, at least two or more developing magnetic rolls having mutually different rotation directions are provided so as to face the surface of the electrostatic image carrier, and are provided below the developing magnetic roll. The developer drawn up by the magnetic roll for transportation provided is distributed and supplied to the plurality of magnetic rolls for development, and the magnetic brush is formed by the developer adsorbed on the magnetic rolls for development, and an electrostatic image is formed by the magnetic brush. In a developing device for developing the electrostatic latent image formed on the holding body,
A developer delivering magnetic roll is provided between at least one developing magnetic roll and the carrying magnetic roll, and the developer drawn up by the carrying magnetic roll is supplied to the developer delivering magnetic roll via the developer delivering magnetic roll. Since the toner is supplied to the rolls, the developer can be stably delivered to and from the plurality of developing magnetic rolls even if the transporting magnetic rolls and the developing magnetic rolls are provided too far apart.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a developing device according to the present invention.

[Explanation of symbols]

Reference numeral 1 is a housing, 2 is a transporting magnetic roll, 3, 4, 5 and 6 are developing magnetic rolls, 7 is a developer delivering magnetic roll, 1
Reference numeral 0 is an electrostatic image carrier.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Doi 1060 Takeda, Katsuta-shi, Ibaraki Hitachi Koki Co., Ltd. (72) Inventor Otsume Yukio 1060 Takeda, Katsuta, Ibaraki Hitachi Koki Co., Ltd. (72) Inventor Yoichi Takeuchi, 1060 Takeda, Katsuta, Ibaraki, Hitachi Koki Co., Ltd. (72) Inventor, Kotaro Yamada, 1060, Takeda, Katsuta, Ibaraki, Hitachi, Ltd. (72) Inventor, Yoshio Ogura, Katsuta, Ibaraki 1060 Ichitakeda Hitachi Koki Co., Ltd.

Claims (1)

[Claims] 1. At least two developing magnetic rolls having mutually different rotating directions are provided facing the surface of the electrostatic image carrier, and are pumped up by a transporting magnetic roll provided below the developing magnetic roll. The developer is distributed and supplied to the plurality of developing magnetic rolls, and a magnetic brush is formed by the developer adsorbed on the developing magnetic rolls, and at the same time, the electrostatic latent image formed on the electrostatic image holding member by the magnetic brush is formed. In a developing device for developing, a developer delivering magnetic roll is provided between at least one developing magnetic roll and the carrying magnetic roll, and the developer drawn up by the carrying magnetic roll is used as the developer delivering magnetic roll. A developing device for an electrophotographic apparatus, characterized in that the developing device is supplied to a developing magnetic roll via a developer.