JPH08677Y2 - Development device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a developing device of an electrostatic image forming apparatus, and more specifically, a developer is biased even if the image forming apparatus is not installed properly. The present invention relates to a developing device.

[Prior art]

An example of this type of developing device is, for example, Japanese Patent Laid-Open No. 58-115461.
The one disclosed in the publication is known. In the developing device disclosed in the above publication, one paddle provided with a guide means for guiding the developer in the horizontal axis direction of the paddle (horizontal direction) is used.
The developer is stirred not only in the vertical direction but also in the horizontal direction. Further, for example, JP-A-58-55955 and JP-A-58-654.
In the developing device disclosed in Japanese Patent Laid-Open No. 60, two developer paddles, one for moving the developer to the center of the horizontal axis of the panel and the other for moving the paddles to both ends, are used to stir the developer in the left-right direction.

[Problems to be solved by the device]

In recent years, home-use or personal small-sized portable image forming apparatuses have been widely used, and the image forming apparatus is often portable and its installation location is not limited.

Therefore, the image device built in the device is not always used in a horizontal state. As described above, when the image device is used while being tilted, the balance of the feeding of the developer is deviated due to the weight. In particular, when the developing device is tilted in the axial direction, the developer is unevenly distributed at one end of the developing device.

As a result, the unevenly distributed developer may be abnormally compressed, which may cause deterioration of the developer or generation of aggregates.
Further, uneven distribution of the developer inevitably results in uneven distribution of the toner amount, so that density unevenness in the axial direction occurs in the copy image. Further, the unevenly distributed toner around the horizontal axis of the rotating paddle and the bearing may be welded, and the developing device may be locked.

Further, in the developing device in which the developer is agitated left and right by one paddle as described above, the developer is conveyed in a fixed direction at the tip of the blade and in the opposite direction near the horizontal axis of the paddle. It Therefore, the developer may be excessively biased at a portion inclined to the side where the developer is conveyed low.

On the other hand, in the developing device using the two paddles, the device itself is bulky and is not particularly suitable for a portable image forming device.

Therefore, it is an object of the present invention to provide a developing device in which the developer is not unevenly distributed even when the image device is placed in an inclined state.

[Means for solving the problem]

To achieve the above object, the main means adopted by the present invention comprises a blade having at least a rake angle at its tip and having a notch hole between the tip and the horizontal axis of the paddle. In a developing device having a paddle that rotates so as to stir and convey the developer between the tip portion and the notch hole, the developer is provided at the tip portion and interferes with the developer when the paddle rotates. A developing device characterized by comprising a mechanism for bringing the developer only to the central portion of the paddle horizontal axis and a mechanism provided near the paddle horizontal axis for bringing the developer only to both ends of the paddle horizontal axis. Is.

[Action]

According to the present invention, the developer scooped up at the tip of the blade by the rotation of the paddle is agitated by the mechanism provided at the tip to move the developer only to the central part of the paddle horizontal axis, so that the paddle horizontal axis It is stirred while being drawn to the center. Subsequently, the developer, which is agitated by a mechanism that is provided near the paddle horizontal axis and moves the developer only to both ends of the paddle horizontal axis, is agitated to both ends of the paddle horizontal axis while being agitated. That is, since the developer is equally divided and agitated so as to circulate between the central portion and both end portions in the paddle horizontal axis direction in a short time, the developer is not biased to one end.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. First here
FIG. 2 is a side sectional view showing a main part of a developing device according to an embodiment of the present invention, and FIG. 2 is a plan view showing a paddle included in the developing device.

It should be noted that the embodiments described below do not limit the technical scope of the present invention.

In the developing device 1 according to the present embodiment, as shown in FIG. 1 and FIG. 2, a paddle 2 for stirring and transporting the developer 9 is provided in a casing 12 so as to be rotatable, and the paddle 2 is parallel to the paddle 2. The developing sleeves 11 are adjacent to each other. The paddle 2
Both the developing sleeve 11 and the developing sleeve 11 are adapted to rotate counterclockwise in the drawing (FIG. 1).

The paddle 2 has a horizontal shaft 4 on which a plurality of blades 6 acting as stirring blades are fixed. The blade 6 has a cutout hole 5 formed in a portion between the tip portion 3 and the horizontal shaft 4. The tip 3 of the blade 6 has a solid line B
It is bent at a portion indicated by and has a rake angle θ with respect to the developer 9.

A plurality of guide blades 7 that attract the developer when the paddle 2 is rotated are formed on the side of the notch 5 of the tip portion 3 so as to project in the traveling direction of the blade 6. The guide vanes 7 are
The end portion of the horizontal shaft 4 is inclined so that the end portion of the horizontal shaft 4 faces the central portion of the horizontal shaft 4 in the axial direction. Further, a spiral protrusion 8 is provided near the center of the horizontal shaft 4 in the axial direction. The spiral projection 8 is formed in a spiral shape so as to rotate together with the horizontal shaft 4 and bring the peripheral developer 9 from the central part of the horizontal shaft 4 to the end parts on both sides.

It should be noted that the developer 9 of the spiral projection 8 is arranged in the horizontal axis direction.
The range that can interfere with the guide blade 7 is set to be narrower than the range by the guide vanes 7. This is because it is sufficient for the spiral projection 8 to act only on the developer 9 excessively moved to the central portion, and the developer 9 is developed. This is to prevent uneven distribution in both axial ends of the device 1.

Therefore, in the developing device 1 configured as described above,
When the paddle 2 is rotationally driven, the developer 9 is scooped up by the tip portion 3 of the blade 6. Then, when the inclination of the blade 6 inclines low toward the guide vanes 7 as the paddle 2 rotates,
A part of the developer 9 on the tip portion 3 begins to slip, and the guide blade 7
It moves along with and is brought near the central part of the horizontal axis 4 (arrow c). Further, the developer 9 comes into contact with the spiral projection 8 and is drawn to both sides of the horizontal shaft 4 and drops to the bottom of the casing 12, and the developer 9 returned from the developing sleeve 11 is returned.
Merge with (arrow b). On the other hand, the developer 9 that has not slipped off from the tip portion 3 is the developing sleeve 11 as shown by the arrow a.
Is conveyed to the outer peripheral surface of.

As described above, a part of the developer 9 is not only agitated in the transport direction of the developer 9 by the mechanical force from the rotational driving of the paddle 2, but also divided equally into the horizontal axis 4 in a short time. Since the liquid is circulated and stirred, it is not unevenly distributed in the developing device 1 even when the developing device 1 is placed at an inclination.
Further, the toner 10 and the developer 9 can be efficiently stirred even when the toner 10 is replenished in the apparatus.

[Effect of device]

According to the present invention, as described above, at least the tip portion has a rake angle, and the blade is provided with a notch hole between the tip portion and the paddle horizontal shaft. In a developing device having a paddle that rotates so as to agitate and convey between the portion and the cutout hole,
A mechanism which is provided at the tip portion and interferes with the developer when the paddle is rotated to move the developer only to the central portion of the paddle horizontal axis; and a mechanism which is provided near the paddle horizontal axis and which holds the developer at both ends of the paddle horizontal axis. Since the developing device is characterized in that it is provided with a mechanism that only moves to the side, the developer is divided into equal parts, and each developer circulates in a short time between the central portion in the paddle horizontal axis direction and both end portions. Be stirred. Therefore, even if the developing device is placed in an inclined state, the uneven distribution of the developer to the lower side is immediately eliminated. As a result, density unevenness does not occur in the copied image, and it is possible to prevent deterioration of the developer and generation of aggregates. Further, since the density of the developer does not become dense near the bearing of the horizontal axis of the paddle, it is possible to prevent the developing device from being locked due to toner adhesion.

Further, the two developer streams formed on the left and right sides of the paddle violently collide with each other in the central portion of the paddle, so that the agitation of the developer is much promoted as compared with the above conventional technique.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an essential part of a developing device according to an embodiment of the present invention, and FIG. 2 is a plan view showing a paddle included in the developing device. [Explanation of reference symbols] 1 ... Developing device, 2 ... Paddle 3 ... Tip part, 4 ... Horizontal shaft 5 ... Notch hole, 6 ... Blade 7 ... Guide vane, 8 ... Spiral protrusion 9 ... Developer

Claims (1)

[Scope of utility model registration request] 1. A blade having at least a rake angle at its tip and having a notch hole formed between said tip and the horizontal axis of the paddle, and a developer is provided between said tip and said notch hole. In a developing device having a paddle that rotates so as to stir and convey between them, a developer is provided at the tip portion and interferes with the developer when the paddle rotates, and brings the developer only to the central portion of the horizontal paddle axis. A developing device comprising: a mechanism; and a mechanism that is provided in the vicinity of the paddle horizontal axis and moves the developer only to both ends of the paddle horizontal axis.