JPH05134538A - Developing device - Google Patents

Abstract

PURPOSE:To detect the moving direction of toner in a toner reflux area where toner removed by a toner layer thickness regulating member goes toward a toner stirring part by providing a toner moving direction detecting plate in the toner reflux area. CONSTITUTION:The toner moving direction detecting plate 12 turnably supported on the side plate of a developing device 2 through a shaft 13 is provided at a part which is positioned in the toner reflux area 11 in the nearly central part between a toner stirring part 4 and a developing roller 8. When the amount of toner in a developer container 3 is large, the inflow pressure of the toner to the area 11 is made high, so that it overcomes the pressure of the toner in the area 11, and the plate 12 is turned and displaced in a direction B, that is, on an opposite direction side to the reflux direction R of the toner. On the other hand, when the amount of toner in the developer container 3 is small, the toner removed by the toner layer thickness regulating member 9 moves in the reflux direction R and the plate 12 is turned and displaced in a direction A, that is, on the reflux direction R side of the toner. Thus, the moving direction of the toner in the vicinity area of the roller 8 and the member 9 is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner carrier, which is rotatably driven, carries toner on the surface thereof and conveys the toner on the toner carrier by a toner layer thickness regulating member brought into contact with the toner carrier. After a part of the toner is removed and the layer thickness of the toner is regulated, the electrostatic latent image formed on the latent image carrier is developed in the developing area where the latent image carrier and the toner carrier face each other. The present invention relates to a developing device that visualizes an image with toner after the layer thickness is regulated.

[0002]

2. Description of the Related Art A dry developing device is widely used in an image forming apparatus such as an electronic copying machine, a laser printer or a facsimile, which obtains a recorded image by visualizing an electrostatic latent image formed on a latent image carrier. ing. Of such developing devices,
A developer of a type in which a carrier-free one-component toner (one-component developer) is used as a developer, the toner is supplied onto the peripheral surface of a toner carrier, and the supplied toner is formed as a thin layer before development. The device is known.

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention. Here, while borrowing FIG. 1 and clarifying the overall configuration of this developing device, there is a problem with the conventional developing device of the above-mentioned type. The points will be described below.

In FIG. 1, reference numeral 1 denotes a drum-shaped photoconductor which is an example of the constitution of a latent image carrier, and a developing device 2 is provided so as to face the drum-shaped photoconductor. The developing device 2 is provided with a developing roller 8 which is an example of the configuration of a toner carrier, and
The photoconductor 1 and the photoconductor 1 are driven to rotate in the directions indicated by the arrows.

A one-component toner (not shown) is accommodated in the developing container 3 of the developing device 2, and the toner contained therein is agitated by the toner agitating portion 4 and is made of a soft elastic material such as a sponge roller. It is supplied onto the developing roller 8 via the supply roller 7. That is, the toner is supplied by the toner supply roller 7 so that the toner is rubbed against the developing roller 8.

In this way, the toner is supplied, and the supplied toner is carried while being carried on the developing roller 8. Reference numeral 9 indicates a toner layer thickness regulating member. The toner layer thickness regulating member 9 has a base end side fixed to the developing container 3 and a free end side abutting on the developing roller 8 via the toner. ..

Part of the toner conveyed on the developing roller 8 is removed by the toner layer thickness regulating member 9,
It is regulated to a layer thickness suitable for development. Part of the removed toner is guided in the R direction and returned to the toner stirring unit 4.
That is, the toner is allowed to flow back toward the toner stirring section 4. Hereinafter, the R direction will be referred to as the “reflux direction”.

On the other hand, the toner on the developing roller 8 whose layer thickness is regulated becomes a thin layer after the regulation and is carried on the developing roller 8 so that the photoconductor 1 and the developing roller 8 face each other. In the area 10, the electrostatic latent image already formed on the photoconductor 1 is visualized. Such a latent image is formed by charging the photoconductor 1 and exposing the charged surface to an image, and a visible image formed as a toner image on the photoconductor 1 is transferred to a transfer material (not shown). The image is transferred and fixed on the transfer material by the fixing device.

Here, the toner layer thickness regulating member 9 is arranged so that its free end side is on the downstream side with respect to the developing roller 8 in the rotational direction thereof. An area surrounded by the member 9, the developing roller 8, the toner stirring section 4, etc., and relatively close to the toner layer thickness regulating member 9 and the developing roller 8 is a substantially triangular void area as shown in the figure. ..

A two-dot chain line area indicated by reference numeral 11 is such a triangular area, and this area is a toner recirculation area when the toner removed by the toner layer thickness regulating member 9 goes to the toner stirring section 4.

In such a toner recirculation region 11,
The toner recirculates in the R direction, and this recirculation action works in opposition to the action of guiding the toner toward the developing roller 8 by the toner stirring unit 4.

When the amount of toner in the developing container 3 is very large, for example, when the toner is full, the toner sent from the toner agitating section 4 gradually flows into the toner recirculation region 11. The toner in this region tends to be compressed, the pressure of the toner in this region increases, and the toner layer thickness regulating member 9 is pushed up by the toner.

In this case, the layer thickness of the toner fluctuates, and when the layer thickness fluctuates, the density of the recorded image fluctuates, which causes deterioration of the image quality. For example, when the amount by which the toner layer thickness regulating member 9 is pushed up increases, the toner layer thickness increases, the image density abnormally increases, and the background stain occurs. From this point, it is understood that the toner layer thickness depends on the amount of toner in the developing container 3.

When the amount of toner in the developing container 3 is large, the toner removed by the toner layer thickness regulating member 9 is less likely to flow back in the R direction, and the area 11 loses its function as a return area. At this time, the toner recirculation region 1
The toner of No. 1 is compressed, and the toner layer thickness regulating member 9 is pushed up by this compressed toner, but at this time, the toner in that area is positively collected by the toner stirring unit 4. For example, such pushing up of the toner layer thickness regulating member 9 can be eliminated.

On the other hand, when the amount of toner in the developing container 3 becomes small, the toner removed by the toner layer thickness regulating member 9 will be returned in the R direction, but since the absolute amount of toner is small, the toner If the ability to convey toner from the agitator 4 is always constant, the developing roller 8
The amount of toner supplied to the printer also decreases. Then, the layer thickness of the toner is also reduced, and the image density is lowered. In such a case, if the amount of toner conveyed from the toner agitating unit 4 can be increased, such a decrease in image density can be prevented.

In any case, if the moving direction of the toner in the toner recirculation region 11 can be detected, the amount of the toner in the developing container 3 can be grasped and the problem as described above can be dealt with. Of.

A developing device using this type of one-component developer has already been proposed by JP-A-63-243977. Further, as a similar technique of this kind, Japanese Patent Laid-Open No. 57-119383 and Japanese Utility Model Laid-Open No. 60-
Japanese Patent Laid-Open No. 191059 and Japanese Patent Laid-Open No. 62-4367 have been proposed, and these examples do not detect the moving direction of toner, but detect the amount of toner in the developing container. ing. In addition, actual development Sho 62-2
In the example according to Japanese Patent No. 7360, similarly, the moving direction of the toner is not detected, but the pressure of the toner in the developing container is relaxed.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner carrier and a toner layer thickness regulating member in a region surrounded by a toner carrier, a toner layer thickness regulating member and a toner stirring section. It is an object of the present invention to provide a developing device capable of detecting the toner moving direction or toner pressure in a near area.

[0019]

In order to achieve the above object, the present invention has a toner layer thickness in which toner is carried on the surface of a toner carrier which is rotationally driven and conveyed, and brought into contact with the toner carrier. The regulation member removes a part of the toner on the toner carrier and regulates the layer thickness of the toner, and then the latent image carrier is carried in the developing area where the latent image carrier and the toner carrier face each other. In a developing device for visualizing an electrostatic latent image formed on a body with toner after a layer thickness is regulated, a developing device has a toner stirring section for stirring toner supplied to a toner carrier, and this toner stirring section, In the area between the toner carrier and the toner removed by the toner layer thickness regulating member, the toner is moved to the toner recirculation area toward the toner stirring section. When the amount of toner in the developing device is small, the toner is displaced toward the toner recirculation direction. However, if the amount of toner is large And it proposes a structure in which a toner moving direction detection plate to be displaced toward the direction opposite to its reflux direction.

The toner agitator has an agitator which is rotationally driven in a direction in which the agitated toner is conveyed toward the toner carrier, and a sub-agitator which is rotationally driven in a direction opposite to the rotational direction of the agitator. However, it is effective that the sub-agitator among these is a sub-agitator that is rotationally driven when the toner movement direction detection plate is displaced to the side opposite to the recirculation direction.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic constitution and operation of the developing device 2 of the embodiment shown in FIG. 1 are as described above, and it has the toner stirring section 4 for stirring the toner to be supplied to the developing roller 8. There is. In this embodiment, the toner stirring unit 4 has an agitator 5 and a sub-agitator 6 which have the same shaft as the center of rotation.

A toner movement direction detection plate 12 is provided at a portion located in the toner recirculation region 11, which is a substantially central portion between the toner agitating portion 4 thus constructed and the developing roller 8. There is. As shown in FIG. 2, a shaft 13 fixedly supporting the toner movement direction detection plate 12 is rotatably supported by a side plate 14 of the developing device, and a shutter plate 15 is fixed to a shaft portion extending outside the side plate. It is equipped.

Reference numerals 16 and 17 respectively indicate a light emitting element and a light receiving element which constitute a photo sensor. For example, when the toner moving direction detecting plate 12 is in a vertical position,
The detection light from the light emitting element 16 is blocked by the shutter plate 15, does not reach the light receiving element 17, and is turned off.

When the amount of toner in the developing container 3 is large, the pressure of the toner flowing into the area 11 increases, so that the toner pressure in the area 11 is overcome, and the toner movement direction detection plate 12 is rotated and displaced in the B direction. Be done. That is, the toner movement direction detection plate 12 is rotationally displaced to the side opposite to the R direction, which is the toner circulation direction.

On the other hand, when the amount of toner in the developing container 3 is small, the toner removed by the toner layer thickness regulating member 9 smoothly moves in the R direction which is the recirculation direction. Toner movement direction detection plate 1
2 is rotationally displaced in the A direction. That is, the toner movement direction detection plate 12 is rotationally displaced toward the toner circulation direction.

On the other hand, when the amount of toner is large, the toner removed by the toner layer thickness regulating member 9 is less likely to flow back in the R direction, and the toner conveying force from the toner agitating section 4 becomes superior. The toner movement direction detection plate 12
Will move in the B direction. In any case,
The detection plate 12 detects the moving direction of the toner and detects whether the toner easily flows back.

For example, assuming that the amount of toner in the developing container 3 is large, at this time, the toner movement direction detection plate 12 shown in FIG. 2 is rotationally displaced in the direction of arrow B. Then, the shutter plate 15 is also rotationally displaced in the same direction, whereby the detection light from the light emitting element 16 reaches the light receiving element 17, which is turned on. After all, it is possible to detect whether the amount of toner in the developing container 3 is large by turning this element on and off.

When the amount of toner in the developing container 3 is large, in the conventional developing device, the toner layer thickness regulating member 9 is pushed up and the toner layer thickness fluctuates, as described above.

The agitator 5 of the toner stirring unit 4 is constantly driven to rotate in the direction of the arrow shown in the drawing when the developing device 2 is operated so that the stirred toner is directed toward the toner supply roller 7 and the developing roller 8. On the other hand, the sub-agitator 6 is rotationally driven in the direction opposite to the rotational direction of the agitator 5 when it is determined that the toner amount in the toner container 3 is excessive.

That is, the toner movement direction detection plate 12 is B
When the toner in the area 11 is detected to be excessively present, the compressed toner in the area 11 is positively moved by rotating the sub-agitator 6 which has been stopped until now. The toner layer thickness regulating member 9 is prevented from being pushed up by the toner. During this time, the main agitator 5 continues to rotate to feed the toner toward the toner supply roller 7. By such a series of operations, the supply and the recirculation of the toner are carried out in a good balance, and it is possible to prevent the toner layer thickness regulating member 9 from being pushed up or the supply of the toner to fall short.

When the amount of toner in the developing container 3 becomes small, the toner movement direction detection plate 12 is rotationally displaced in the direction A. At this time, the rotation speed of the agitator 5 is increased or the sub agitator is rotated. 6 may be rotationally driven in the same clockwise direction as the agitator 5 to increase the toner supply amount. In any case, such a function can be achieved if it is possible to detect in which direction the toner moves between the developing roller 8 and the toner stirring unit 4. The sub-agitator 6 is not necessarily required when the developing device is configured so that the rotation speed of the agitator 5 is increased or decreased by the displacement of the toner moving direction detection plate 12.

[0032]

According to the developing device of the present invention, since the moving direction (toner behavior) of the toner in the vicinity of the toner carrier and the toner layer thickness regulating member can be detected, the toner layer thickness regulating member can be detected. It is possible to judge whether the toner removed by the recirculation is easy to reflow,
Further, since the amount of toner in the developing device can also be indirectly detected, it becomes possible to eliminate excess or deficiency of the supply amount.

According to the developing device of the second aspect, it is possible to prevent the layer thickness of the toner thin layer from changing, and it is possible to obtain a stable and high-quality image without density fluctuation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a developing device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a toner movement direction detection plate constituting portion of the developing device according to the embodiment of the present invention.

[Explanation of symbols]

 2 developing device 4 toner agitating section 8 developing roller as a toner carrier 9 toner layer thickness regulating member 10 developing area 12 toner movement direction detecting plate

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Yuichi Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh Co., Ltd. (72) Akira Sawada 1-3-6 Nakamagome, Ota-ku, Tokyo Stocks Company Ricoh

Claims (2)

[Claims] 1. A surface of a toner carrier that is rotationally driven,
The toner image is transferred after carrying the toner, and the toner layer thickness regulating member abutting on the toner carrier removes a part of the toner on the toner carrier and regulates the layer thickness of the toner. In a developing device that visualizes an electrostatic latent image formed on a latent image carrier with toner after layer thickness regulation in a developing area where the carrier and the toner carrier face each other, A toner stirring unit that stirs the supplied toner is provided. In a region between the toner stirring unit and the toner carrier, the toner removed by the toner layer thickness regulating member flows toward the toner stirring unit. In the area, a toner movement direction detection plate is provided, which is displaced toward the toner recirculation direction side when the toner amount in the developing device is small, and displaced toward the side opposite to the toner recirculation direction side when the toner amount is large. And developing device. 2. The toner agitator has an agitator that is rotationally driven in a direction in which the agitated toner is conveyed toward a toner carrier, and a sub-agitator that is rotationally driven in a direction opposite to the rotational direction of the agitator. 2. The developing device according to claim 1, wherein the sub-agitator is a sub-agitator that is rotationally driven when the toner movement direction detection plate is displaced to the side opposite to the recirculation direction.