JP3591615B2 - Developing device for electrophotographic equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a developing device for an electrophotographic apparatus.
[0002]
[Prior art]
In a developing device of an electrophotographic device used for a printer, etc., a stirrer of a cross-mixing structure which is inexpensive and does not require a driving force is used as a stirrer for equalizing the toner concentration of a developer which has been consumed and becomes non-uniform during development. Is 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 showing a configuration of a developing device according to the related art, and FIG. 4 is a perspective view showing a stirring state of a developer in a cross mixer.
[0004]
In the drawing, developing magnetic rolls 4 and 5 are attached to the inside of a developing container 1 so as to face a transporting magnetic roll 2 and a photoreceptor 3, and are rotated at substantially the same peripheral speed in a direction indicated by an arrow in FIG. I do. 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 separating plate 7c facing the developing magnetic roll 4 is provided. A cross mixer 8 having a similar configuration is attached to the developing magnetic roll 5.
[0005]
Further, a stirring paddle 9 is mounted adjacent to the transporting magnetic roll 2, and rotates in the direction of the arrow in the figure by appropriate power in conjunction with the developing magnetic rolls 4, 5 and the transporting magnetic roll 2. Further, a toner density sensor 10 is attached to the developing container 1 below the stirring paddle 9.
[0006]
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 that has come into contact with the photoreceptor 3 and completed development falls into the cross mixer 7, and is conveyed and agitated in the axial direction by the plurality of deflecting plates 7a and 7b, so that it is unevenly developed by the development. The resulting toner concentration is made uniform, dropped from the cross mixer 7, merged with the developer 13, and sent to the transport magnetic roll 2 again. On the other hand, the developer 13b on the side of the developing magnetic roll 5 drops into the cross mixer 8, is conveyed and agitated in the same manner as described above, is sent under the toner replenishing roll 12, and is sent by the agitation paddle 9, and the toner density sensor 10 Is measured and sent to the transport magnetic roll 2 again.
[0007]
Further, when the toner in the developer is consumed during the development process and the toner concentration decreases, and when the toner concentration measured by the toner concentration sensor 10 falls below a certain level, the toner replenishing roll 12 is driven and the toner supply roller 12 is driven. The toner 14 in the container 11 is supplied to the developer.
[0008]
[Problems to be solved by the invention]
Here, the problems of the related art will 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 pole of the developing magnetic roll 4 and variations in the magnetization of the roll. Occurs. For example, when the developer 13a drops in the direction of α, the developer 13a flows uniformly into the deflecting plates 7a and 7b, so that the developer 13a dropped from the cross mixer 7 is uniformly transported to the near side and the far side. Therefore, no offset occurs. However, when the developer 13a drops in the direction of β, 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 developer on the rear side where the amount of the developer has increased 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.
[0009]
On the other hand, the developer 13b on the developing magnetic roll 5 may also be offset for the same reason as described above, and the toner concentration sensor 10 detects a decrease in the toner concentration. When the developer 14 is replenished with the developer, the toner density on the front side where the developer amount has increased is low and the print becomes lighter, and the toner density on the rear side where the developer amount has decreased is high and the print becomes darker. It becomes uneven. In addition, since the toner density sensor 10 cannot accurately detect the toner density due to the uneven toner density, excessive or too small toner replenishment is performed and the print density becomes darker or lighter as a whole. I do.
[0010]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device that prevents the developer from being biased and does not cause print density unevenness due to the bias.
[0011]
[Means for Solving the Problems]
The above object is achieved by providing a developer regulating plate for regulating a position where the developer falls from the developing magnetic roll to the cross mixer above the cross mixer.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail using specific examples. 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 state in which the developer is stirred by the cross mixer.
[0013]
In the figure, reference numerals 1 to 14 are the same as those described in the related art. A developer regulating plate 15 is provided above the cross mixer 7 on the developing magnetic roll 4 side of the separation plate 7c, and a developer regulating plate 16 is similarly provided above the cross mixer 8.
[0014]
Hereinafter, the effect of preventing the misalignment in the developing device configured as described above will be described. The development process is the same as that described in the prior art. In the present invention, when the developer 13a after development falls from the developing magnetic roll 4 to the cross mixer 7, the developer regulating plate 15 provided above the cross mixer 7 prevents the developer 13a from falling in the β direction. Can be prevented and can be dropped only in the α-direction, so that the deviation can be prevented.
[0015]
In addition, the cross mixer 8 can also control the position at which the developer falls by the developer restricting plate 16 in the same manner, so that the deviation can be prevented.
[0016]
【The invention's effect】
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 showing a stirring state of a developer in a 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 conveying magnetic roll, 3 is a photoreceptor, 4 and 5 are developing magnetic rolls, 6 is a doctor plate, 7 and 8 are cross mixers, 9 is a stirring paddle, 10 is a toner density sensor, and 11 is toner. A container, 12 is a toner supply roll, 13 is a developer, 14 is a toner, and 15 and 16 are developer regulating plates.

Claims (1)

A plurality of developing magnetic rolls arranged opposite to the photoreceptor, and a developer provided on one surface of the separation plate and dropped from above the separation plate toward the front side in the longitudinal direction of the separation plate. Developing device having a deflecting plate and a cross mixer provided on the other surface of the separating plate and provided with a deflecting plate for dropping the developer fed from above the separating plate toward the back in the longitudinal direction of the separating plate. A device,
In a developing device of an electrophotographic apparatus in which the cross mixer is arranged at a position where the developer after development falls from each of the developing magnetic rolls ,
A developing device for an electrophotographic apparatus, wherein a developer regulating plate is provided above a separation plate of the cross mixer to regulate a position at which the developer falls on the cross mixer .

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