JPS6324267A - Developing device - Google Patents

Abstract

PURPOSE:To obtain an image uniform in a longitudinal direction by increasing the rotational radius of a stirring member around an approximately center part of the member in the longitudinal direction continuously or like steps in the direction to both the end sides. CONSTITUTION:Since the stirring rod 1 is constituted so that the rotational radius is increased from the center of the longitudinal direction to the end parts, the relation between the rotational radii r1, r1' near the end parts and the rotational radii r2, r2' near the center satisfies r1, r1' > r2, r2'. The stirring rod formed such a shape makes it possible to supply the uniform quantity of developer in a hopper 12 to a developing sleeve 5 and maintain a longitudinally uniform picture quality.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a developing device for developing an electrostatic latent image in an electrophotographic copying machine, a 7mm facsimile machine, etc., and a particularly effective one is a small-sized one. , developer? The present invention relates to a developer agitation mechanism in a disposable, easy-to-use developing device whose life span ends when the developing device is used up.

[Background of the invention]

Conventionally, this type of device has been used for two-component development using a developer consisting of carrier and toner, and for one-component development using a developer containing magnetic powder such as iron powder dispersed in resin. Commonly used.

In these systems, for example, in the two-component development method, there is a stirring means for sufficiently mixing and stirring the toner supplied from the developer container with the carrier to impart sufficient electric charge to the toner, and a -component. In the developing method, the newly supplied developer from the developer container and the developer that has not been developed in the developing section and has returned to the developer are mixed and stirred to separate the newly supplied developer and the undeveloped developer. A stirring means is used to uniformly mix the developer in the same state. Conventionally, in a small disposable type developing device, the stirring means is a line whose rotating shape is cylindrical, as shown in FIG. A type in which a stirring member is rotated is generally adopted. That is, the linear stirring member 20 having an eccentric portion stepped and bent with respect to the rotation axis A-A forms a cylindrical rotation locus along a developing sleeve or the like having a predetermined length in the female direction. It is configured to provide an agitating action to the developer stored in this portion.

By the way, in a stirring mechanism having such a stirring means, both ends of the stirring member are supported by a side plate (fixed support) of the developing device, and one end is driven to rotate. Although it is normal, since the strength of the wire is weak, there is a difference between the torque on the driving side and the torque on the non-driving side, which inevitably causes twisting of the stirring member.

When the agitating member is twisted, fluidity in the axial direction is applied to the agitated developer, which causes the developer to shift toward the non-driving side, causing the developer on the driving side to [Object of the Invention] The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional example, and its purpose is to solve the problem that the developing sleeve is consumed in the longitudinal direction in the developing device. The object of the present invention is to provide a stirring means that makes it possible to maintain the developer t uniformly.

[Summary of the invention]

A feature of the developing device according to the present invention, which has been made to achieve such an object, is that an agitating means provided in the developing container to serve as a developer conveying means such as a developing sleeve is rotated by a fixed support. It is formed by a stirring rod that is supported and has rotating shaft portions at both ends with one end serving as a driving shaft and the other end serving as a driven shaft, and a bent and eccentric intermediate portion, and the eccentric shape of the intermediate portion of the stirring rod is as follows. The rotation radius increases from approximately the center in the longitudinal direction toward both ends.

In the above configuration, increasing the radius of rotation may mean that the stirring bar is inclined with respect to the axis from the center in the longitudinal direction toward the ends, or that it is provided in a step-like manner, and is preferably provided. are provided substantially symmetrically on both end sides with respect to the central portion in the longitudinal direction. Considering the offset, the radius of the offset 9 portion may be made larger, or it may be asymmetrical.

The degree of the increase in the inclined linear shape or stepwise shape depends on the internal field of the developer container, etc., but generally, the dimension of the maximum rotation radius portion on both ends with respect to the longitudinal dimension is 10/nm to 50/nm.
In this embodiment, it is suitably realized that the temperature is about 20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/20/2000/2000, preferably about 20/30/100/200/200/200/2000/2000/2000/2000/2000/2000/2000/2000.

It is preferable that the increase in diameter at both ends relative to the center be within 10W, as this will result in further uniformity.

The stirring rod serving as the stirring means is generally made of a metal wire made of non-magnetic material such as stainless steel or aluminum.

[Embodiments of the invention]

The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 is a diagram illustrating an example of a general configuration of a developing device using a stirring rod 1t according to the present invention.
The developing sleeve (developer conveying means) 5 is disposed at a lower position within the interior, close to the developing sleeve (developer conveying means) 5, and along the longitudinal direction thereof. As shown in FIG. 2, this stirring rod 1 has two ends la and lb which are rotatably supported by a fixed support (not shown) (side plate of the container).
Extended tips that extend a certain length on opposite sides in the radial direction,
They are connected by a straight line IC inclined with respect to the axis, and one end 1a is connected to a rotational drive mechanism (not shown), and the other end 1b is a driven bearing.

In addition, 5 is a sleeve that carries the developer and rotates in the direction of arrow 11, 6 is a magnet that is arranged inside the sleeve 5 and carries and conveys the developer 10 by its magnetic field, and 7 is the sleeve 5.
This is a blade that regulates the amount of developer applied to the top.

To explain the basic flow of the developer 10 having such a configuration, the developer 10 applied onto the sleeve 5 develops the latent image on the latent image holder (not shown) and then is subjected to development. The developer container 8 is carried with the remaining developer 9 that was left undeveloped and collected in the container 12 by the action of the stirring rod 1.
The new developer 10 supplied from the developer 9 and the residual developer 9 are mixed and newly applied onto the sleeve 5. Due to the configuration in which the radius of one rotation is large, the radius of rotation rllrl' near the end and the radius r2er2' near the center are such that rl, r凰'>
rzsrz', and by adopting the shape of the stirring rod, a uniform amount of the developer in the hole p4-12 is supplied to the developing sleeve 5 in the longitudinal direction, and uniform image quality in the longitudinal direction is maintained. This will have the effect of To explain this specifically, the difference in the stirring radius given by the shape of the stirring rod 1 as described above causes a difference in stirring speed between the ends and the center of the developer, and the developer moves as indicated by the arrows in Figure 2. 3. The developer moves in the direction of ``3'' and collects near the center, but the developer that has gathered in the center is pushed radially outward by the flow of arrows 3 and 3', creating a flow of 4 and 4' in the upper layer, and the developer is developed. Agent arrow 3→4. A flow occurs in the direction of arrows 3'→4', which causes a longitudinal circulation of the developer.

Specifically, the radius of both ends should be in contact with the bottom of the container,
Its radius 'f? , 28 m, the center radius is 20 m,
By continuously changing the range, it was possible to prevent the toner from shifting toward the end, and stable toner replenishment was achieved over the longitudinal direction of the developer carrier, and the developed density was also stabilized.

FIG. 3 shows a stirring rod 13 according to another embodiment of the present invention, and in this example, the rotating shaft core portions 13 a e 1 at both ends
3b, the intermediate portion is formed in a step-like manner to provide the same developer flow as in the previous embodiment. In this example as well, the above-mentioned action has the effect of ensuring an average distribution state of the developer in the longitudinal direction of the stirring rod.

〔Effect of the invention〕

As described above, in the present invention, the stirring member is configured to have a rotation radius that increases continuously or stepwise toward both ends, with the stirring member centered approximately at the center in the longitudinal direction. This has the effect that a uniform distribution of developer is supplied to the sleeve 5, thereby making it possible to obtain uniform image quality in the longitudinal direction.

Furthermore, even if the developer is unevenly distributed due to external factors, the amount of developer can be evenly distributed through the stirring action.
It is also possible to always obtain uniform image quality in the longitudinal direction, which is extremely useful.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing the general configuration of a developing device to which the present invention is applied, FIG. 2 is a front view showing an example of a stirring bar, and FIG. 3 is a front view showing an example of a stirring bar.
The figure shows another example of a stirring rod, and FIG. 4 shows a conventional example of a stirring member (rod). 1.13... Stirring rod 5... Developing sleeve 6.
... Magnet 7 ... Blade 8 ... Developing container 9, 1 o ... Developer 12 ... Hopper 20 ... Stirring member (rod) Honda small□1゛1 Shore 1) Correct line゛?・τ] 1 ・・1 Kota Tani m-1, -11no

Claims (1)

[Claims] a developer container for storing developer; a developer transport means for transporting the stored developer to the surface of the latent image carrier; and a developer transport means arranged along the longitudinal direction of the developer transport means within the developer container, and In the developing device, the developer stirring means is rotatably supported by a fixed support and has a driving shaft at one end and a driven shaft at the other end. It is formed by a stirring rod having rotating shaft portions at both ends forming a shape, and a bent eccentric middle portion, and the eccentric shape of the middle portion of the stirring rod rotates from the approximately central portion in the longitudinal direction toward both ends. A developing device characterized by having a configuration in which the radius increases.