JPH10207198A - Developing device for electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the localization of developer so as to prevent the occurrence of printing density irregularity caused by the localization by providing a developer control board controlling a position where the developer falls from a developing magnetic roll to the cross mixer above the cross mixer. SOLUTION: The developer control board 15 is provided above the cross mixer 7 on the developer magnetic roll 4 side of a separating board, and the developer control board 16 is similarly provided above the cross mixer 8. By this constitution, when the developer 13a obtained after developing falls from the roll 4 to the mixer 7, the board 15 provided above the mixer 7 prevents the developer 13a from falling in a direction (β) and makes the developer fall only in a direction (α); so that the localization can be prevented. The board 16 similarly controls the falling position of the developer on the mixer 8 side, so that the localization can be prevented.

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 used for a printer or the like, a low-cost, non-driving cross stirrer is used as a stirrer for uniformizing the toner concentration of a developer consumed and uneven in development. Mixing structure stirring devices are widely used.

[0003] Problems in the conventional developing device will be specifically described with reference to the drawings. FIG. 3 is a cross-sectional view illustrating a configuration of a developing device according to the related art, and FIG. 4 is a perspective view illustrating a developer stirring state in a cross mixer.

In FIG. 1, a developing magnetic roll 4 and a developing magnetic roll 4
5 is attached and rotates at substantially the same peripheral speed in the direction of the arrow in the figure by an appropriate power such as a motor. A doctor plate 6 faces the developing magnetic rolls 4 and 5 at an appropriate interval, and a cross mixer (stirring device) 7 having a plurality of deflecting plates 7a and 7b on both sides of a separation plate 7c facing the developing magnetic roll 4 , A cross mixer 8 having a similar configuration facing the developing magnetic roll 5.
Are attached.

[0005] A stirring paddle 9 is mounted adjacent to the transporting magnetic roll 2, and rotates in the direction of the arrow by appropriate power in conjunction with the developing magnetic rolls 4, 5 and the transporting magnetic roll 2. Further, a toner concentration sensor 10 is attached to the developing container 1 below the stirring paddle 9.

On the other hand, a toner supply roll 12 is attached to a lower portion of a toner container 11 provided adjacent to the developing container 1, and is driven by an appropriate power. In the developing device, the developer 13 inside the developing container 1 is transported by the rotation of the transporting magnetic roll 2 and delivered to the developing magnetic rolls 4 and 5, and is regulated to an appropriate thickness by the doctor plate 6. 5 is conveyed to the photoreceptor 3.
The developer 13a on the side of the developing magnetic roll 4 which has come into contact with the photoreceptor 3 and completed the development falls to the cross mixer 7 and the plurality of deflection plates 7
The toner is transported and agitated in the axial direction at a and 7b, so that the toner density which has become non-uniform due to the development is made uniform, dropped from the cross mixer 7, merges with the developer 13, and is sent to the transport magnetic roll 2 again. On the other hand, the developer 1 on the developing magnetic roll 5 side
3b is dropped onto the cross mixer 8, conveyed and agitated in the same manner as described above, and then passes under the toner replenishing roll 12 to agitate the paddle 9
The toner density is measured by the toner density sensor 10 and sent to the transport magnetic roll 2 again.

When the toner in the developer is consumed during the development process and the toner density decreases, and when the toner density measured by the toner density sensor 10 falls below a certain level, the toner replenishing roll 12 is turned off. When driven, the toner 14 in the toner container 11 is supplied to the developer.

[0008]

The problems of the prior art will now be described. The developer 13a after the completion of the development in the developing device falls from the developing magnetic roll 4 to the cross mixer 7, but is affected by variations in the mounting angle of the magnetic poles of the developing magnetic roll 4 and variations in the magnetization of the roll, and the falling position varies. Occurs. For example, the developer 13 in the direction of α
When a falls, the developer 13a flows evenly into the deflecting plates 7a and 7b, so that the developer 13a that has fallen from the cross mixer 7 is uniformly conveyed to the near side and the far side, so that no offset occurs. However, the developer 13a in the direction of β
Falls, most of the developer passes through the deflecting plate 7a side, so that the developer 13a dropped from the cross mixer 7 is biased to the back side. In this case, when the developer 13 having a uniform toner concentration transported by the transport magnetic roll 2 from the stirring paddle 9 side merges with the developer 13a dropped from the cross mixer 7, the rear side where the developer amount is increased. , The toner density is low, the print becomes lighter, the toner density on the front side where the developer amount is reduced becomes higher, the print becomes darker, and the print density becomes uneven.

On the other hand, the developer 13b on the developing magnetic roll 5
In some cases, deviation may occur due to the same reason as described above. The toner concentration sensor 10 detects a decrease in toner concentration, and the toner
When the developer is replenished, the toner density on the front side where the amount of developer has increased is low and the print becomes lighter, the toner density on the back side where the developer amount has decreased is high and the print becomes dark, and the print density unevenness Becomes Further, since the toner density sensor 10 cannot accurately detect the toner density due to the non-uniform toner density, excessive or too small toner replenishment is performed and the print density becomes darker or lighter as a whole. I do.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device which prevents the developer from being biased and does not cause print density unevenness due to the bias.

[0011]

The above object is achieved by providing a developer regulating plate above the cross mixer for regulating a position at which the developer falls from the developing magnetic roll to the cross mixer.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail using specific embodiments. FIG. 1 is a sectional view showing an embodiment of the developing device according to the present invention. FIG. 2 is a perspective view showing a developer stirring state in the cross mixer.

In the figure, reference numerals 1 to 14 are the same as those described in the prior art. A developer regulating plate 15 is provided above the cross mixer 7 on the side of the developing magnetic roll 4 of the separation plate 7c, and a developer regulating plate 16 is similarly provided above the cross mixer 8.

Hereinafter, a description will be given of the effect of preventing deviation in the developing device having the above-described configuration. The development process is the same as that described in the prior art. In the present invention, the developer 13a after development is
When the developer 13 a falls from the cross mixer 7, the developer regulating plate 15 provided above the cross mixer 7 prevents the developer 13 a from falling in the β direction and allows the developer 13 a to drop only in the α direction. Can be prevented.

Also, the position of the developer falling on the cross mixer 8 side can be regulated by the developer regulating plate 16 in the same manner, so that the deviation can be prevented.

[0016]

As described above, according to the present invention, it is possible to provide a developing device capable of preventing a bias of a developer and performing printing without causing a print density unevenness due to the bias.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a developing device according to the present invention.

FIG. 2 is a perspective view illustrating a developer stirring state in the cross mixer according to the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of a developing device according to a conventional technique.

FIG. 4 is a perspective view showing a developer stirring state in a cross mixer according to the related art.

[Explanation of symbols]

1 is a developing container, 2 is a transport magnetic roll, 3 is a photoreceptor,
5 is a developing magnetic roll, 6 is a doctor plate, 7 and 8 are cross mixers, 9 is a stirring paddle, 10 is a toner density sensor, 1
1 is a toner container, 12 is a toner supply roll, 13 is a developer, 14 is a toner, and 15 and 16 are developer regulating plates.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Tsukasa Onose 1060 Takeda, Hitachinaka-shi, Ibaraki Prefecture Inside Hitachi Koki Co., Ltd. (72) Inventor Hiroshi Ueno 1060 Takeda, Hitachinaka-shi, Ibaraki Inside Hitachi Koki Corporation

Claims (1)

[Claims] An image forming apparatus comprising: one or more developing magnetic rolls disposed opposite to a photoreceptor; and transports the developer axially forward to a position where the developed developer falls from the developing magnetic roll. A developing device for an electrophotographic apparatus having one or more stirrers of a cross-mixing structure in which a deflecting plate and a deflecting plate to be conveyed to the back side are alternately arranged at equal intervals on both sides of the separation plate. A developing device for an electrophotographic apparatus, wherein a developer regulating plate is provided above the stirring device on the side of the developing magnetic roll of the separating plate.