JPH03196073A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the generation of the unequalness of developers even if the sizes of respective rollers are reduced by setting the rotating speeds of the respective rollers in such a manner that the speed of the 2nd agitating roller is lower than the speed of the developing roller and the speed of the 1st agitating roller is higher than the speed of the developing roller. CONSTITUTION:The developing roller 2, and the 1st agitating roller 3 which agitates the toner replenished into a developing tank 1 and transports the toner to the developing roller 2 side and the 2nd agitating roller 4 disposed between the 1st agitating roller 3 and the developing roller 2 are freely rotatably provided in the developing tank 1 disposed in proximity to a photosensitive body. The rotating speeds V2 to V4 of the respective rollers 2 to 4 are so set that the speed of the 2nd agitating roller 4 is lower than the speed of the developing roller 2 (V4<V2) and the speed of the 1st agitating roller 3 is higher than the speed of the developing roller 2 (V2<V3). Thus, the agitating performance of the developer is improved and the generation of the unequalness of the developers is prevented even if the sizes of the respective rollers 2 to 4 in the developing tank 1 are reduced. The disposition of the agitating rollers in the developing tank to horizontal direction is attained and the miniaturization of the developing device is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a developing device for a copying machine, a laser printer, etc.

<Prior art> With the miniaturization of copying machines, the developing device also needs to be miniaturized, and by miniaturizing each roller in the developing device, the amount of developer that can be put into the developing device is reduced, and the life of the developer is extended. There is no hope of change.

Therefore, by arranging multiple stirring members inside the developing device and making the developing device longer in the horizontal direction to make it thinner, we are able to ensure a sufficient amount of developer and extend the life of the developing device. This makes it possible to respond to the miniaturization of

<Problems to be Solved by the Invention> However, in the above-mentioned developing device, the agitation performance becomes extremely unstable due to the long and thin shape in the horizontal direction.
There is a problem that unevenness occurs in the developer.

In view of the above, the present invention improves the stirring performance of the developer,
Moreover, it is an object of the present invention to provide a developing device which can be miniaturized.

<Means for Solving the Problems> As shown in FIG. 1.2, the means for solving the problems according to the present invention includes a developing roller 2 in a developing tank 1, and stirring the toner supplied in the developing tank 1 with a developer. A second stirring roller 4 disposed between the developing port roller 2 and the first stirring roller 3 is rotatably provided, and the rotational speed of each roller 2.3.4 is V t ,
V 3 and V 4 are set such that the second stirring roller 4 is smaller than the developing roller 2 and the first stirring roller 3 is set larger than the developing roller 2.

<Operation> In the above problem solving means, the replenished toner falls onto the first stirring roller 3. Then, the first stirring roller 3 rotating at high speed causes the development tank! The developer and toner inside are quickly mixed and stirred, the toner rubs against each other, becomes electrically charged, and is sent to the second stirring roller 4. Thereafter, the second stirring roller 4 rotating at a low speed performs stirring in the axial direction of the roller, and the developer within the developer tank 1 is uniformly stirred.

Here, the rotational speed of each roller 2, 3.4 is V! +V
The experimental results regarding the stirring performance of the developer when S*V4 is set as V 4 < V 2 < V s are shown.

First, FIG. 3 shows a comparative study of the flow of developer in the axial direction of the rollers. According to this, the developer is conveyed from the first stirring roller 3 to the second stirring roller 4, and the developer is conveyed to the second stirring roller 4.
is rotating at the same rotational speed as the first stirring roller 3,
The same amount of developer as the developer conveyed from the first stirring roller 3 is further transferred to the developing roller 2 by the second stirring roller 4.
It ends up being transported towards.

However, when the second stirring roller 4 rotates at a lower speed than the first stirring roller 3, a smaller amount of developer is transported toward the developing roller 2 than the amount of developer transported from the first stirring roller 3. It can be seen that since the remaining amount is conveyed in the axial direction, it takes less time for the developer to be uniformly stirred, and the developer flows smoothly in the axial direction of the roller.

Next, FIG. 4 shows a comparative study of the flow of developer between rollers. According to this, the rotational speed v3 of the first stirring roller 3 should be set faster than the rotational speed V4 of the second stirring roller 4. As a result, there is a difference in the flow rate of the developer at each roller 3.4, and the agitation of the developer becomes intense at the boundary.
Therefore, it can be seen that the stirring time between the first stirring roller 3 and the second stirring roller 4 can be shortened, the developer can be conveyed smoothly, and the stirring between the rollers can be performed quickly.

Therefore, even if each roller in the developer tank is downsized, the agitation performance of the developer can be improved, and the occurrence of unevenness in the developer can be prevented. Furthermore, it becomes possible to arrange the stirring roller laterally within the developer tank, and the size of the developing device can also be reduced.

<Example> An example of the present invention will be described below based on the drawings. FIG. 1 is a sectional view of a developing device showing one embodiment of the present invention, and FIG.
FIG. 3 is a perspective view of the first and second stirring rollers, FIG. 3 is a diagram showing the developer stirring performance in the axial direction of the roller, and FIG. 4 is a diagram showing the developer stirring performance in the rotational direction of the roller.

As shown in FIG. 1, the developing device of this embodiment includes a developing roller 2 and toner supplied to the developing tank 1 in a developing tank 1 disposed close to a photoreceptor (not shown). Ada Mikoto → 9 Tsukuda 11. = Bottle-hidden eggplant rack - A beech slag roller 3 and a second stirring roller 4 disposed between the developing roller 2 and the first stirring roller 3 are rotatably provided, and each roller 2, 3
．． 4 rotational speed Vt.

V3. V4 is set such that the second stirring roller 4 is smaller than the developing roller 2 (V4<V2), and the second stirring roller 3 is set larger than the developing roller 2 (V!<V3). be.

The developer tank l has an opening 5 formed on the side facing the photoreceptor, the developer roller 2 is disposed in the opening 5, and the second stirring roller 4 is disposed on the side farther from the photoreceptor than the developer roller 2. The first stirring roller 3 is disposed on a side further apart from the second stirring roller 4.

A toner replenishment port 6 is formed above the first stirring roller 3 and communicates with a toner replenishment tank (not shown). In the figure, 7 is a doctor and 8 is a toner concentration sensor.

The developing roller 2 includes a magnet body 9 that is fitted around a support shaft 1a that is rotatably supported by the developer tank l and fixed to the developer tank l, and a sleeve IO that is rotatably fitted to the outside of the magnet body 9. The sleeve 10 rotates counterclockwise.

The first stirring roller 3 and the second stirring roller 4 are
As shown in the figure, the roller shaft 3 is rotatably supported in the developer tank l.
a, 4a, a large number of elliptical fins 11 externally fitted and fixed at an angle to the roller shafts 3a, 4a, and projecting in the radial direction from the shafts 3a, 4a between each elliptical fin 11. vertical fins 12, and each roller 3.4 rotates in the same direction as the developer roller 2. And, the correction oval fin I! The paper is transported in the axial direction of the rollers, and the vertical fins 12 transport the paper between the rollers.

Each of the rollers 2, 3.4 is rotationally driven by a motor (not shown).

In the above configuration, the toner supplied from the toner supply tank through the toner supply port 6 falls onto the first stirring port 3 . Then, the first stirring roller 3 rotating at high speed quickly mixes and stirs the developer and toner in the developer tank l, and the toner rubs against each other, becomes electrically charged, and is sent to the second stirring roller 4. Thereafter, the second agitation roller 4 rotating at a low speed performs agitation in the roller axial direction, and the developer tank 1 is agitated.
The developer is uniformly stirred within the container.

The sufficiently agitated developer forms spikes on the sleeve 10, and is conveyed to the photoreceptor while the height of the spikes is regulated by the doctor 7.

Here, each roller 2, 3, 4 (7) rotation speed V! ,
Vs.

v4 as in this example, V4 < V! <V
The experimental results regarding the stirring performance of the developer when setting s are shown.

First, the experimental results regarding the stirring performance in the axial direction of the roller are shown in the third section.
As shown in the figure. In this experiment, developers with different concentrations were placed in the front side of the developer tank 1 and on the opposite side across the roller shafts 3a and 4a, and the developer was placed between When the rotation speed of the first stirring roller 3 is increased (V 4 < Va) and when the rotation speed of the first stirring roller 3 and the second stirring roller 4 are made equal (V a = V
, ) is a comparative study of the flow of developer in the axial direction of the roller due to stirring.

According to this, from the first stirring roller 3 to the second stirring roller 4
Although the second stirring roller 4 is rotating at the same rotational speed as the first stirring roller 3, the same amount of developer as the developer transported from the first stirring roller 3 is further transported to the second stirring roller 4. The second stirring roller 4 transports the toner toward the developing roller 2 . However, when the second stirring roller 4 rotates at a lower speed than the first stirring roller 3, a smaller amount of developer is transported toward the developing roller 2 than the amount of developer transported from the first stirring roller 3. It can be seen that since the remaining amount is conveyed in the axial direction, it takes less time for the developer to be uniformly stirred, and the developer flows smoothly in the axial direction of the roller.

Next, FIG. 4 shows the experimental results regarding the stirring performance between the rollers. In this experiment, the first stirring roller 3 and the second stirring roller 4 were
When developers with different concentrations are put into the parts of , and the rotation speed of the first agitation port 3 is made faster than the second agitation roller 4 (V4<VS), the first agitation roller 3 and the second agitation roller When the rotational speeds of 4 are made equal (V s = V 4), the rice between the rollers is 1! This is due to the lack of AI.

According to this, by setting the rotational speed V of the first stirring roller 3 faster than the rotational speed V4 of the second stirring roller 4, a difference appears in the flow rate of the developer at each roller 3.4, and the boundary between the two Since the agitation of the developer becomes more intense during the process, the agitation time between the first agitation roller 3 and the second agitation roller 4 can be shortened, the developer can be conveyed smoothly, and the agitation between the rollers can be reduced. I know it will be done soon.

That is, by setting the rotational speed V4 of the second stirring roller 4 to be the same as or higher than that of the first stirring roller 3, the toner replenished from the toner replenishment port can be sufficiently stirred and smoothly conveyed to the second stirring roller 4. Not only is this impossible, but it also causes uneven density of the developer in the axial direction of the roller.

Therefore, the rotational speed V4 of the second stirring roller 4 is set to be smaller than the rotational speed V of the developing roller 2, and the rotational speed V3 of the first stirring roller 3 is set to be larger than the rotational speed V of the developing roller 2. Therefore, even if each roller is made smaller, the agitation performance of the developer can be improved, and the occurrence of unevenness of the developer can be prevented. Furthermore, it becomes possible to arrange the stirring roller laterally within the developer tank, and the size of the developing device can also be reduced.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, although the first stirring roller 3 and the second stirring roller 4 in this embodiment are formed to have the same diameter, by making the diameter of the second stirring roller 4 smaller than the diameter of the first stirring roller 3,
It is also possible to make a difference in rotation speed. Moreover, the shapes of both rollers are not limited to the same one, but may be different shapes.

<Effects of the Invention> As is clear from the above description, according to the present invention, a developing roller is provided in a developing tank, and a first stirring unit that mixes the toner supplied to the developing tank with the developer and transports the toner to the developing roller side. A roller and a second stirring roller disposed between the developing roller and the first stirring port roller are rotatably provided, and the rotational speed of each roller is such that the second stirring roller is smaller than the developing roller. in,
By setting the first stirring roller larger than the developing roller, it is possible to improve the stirring performance of the developer even if each roller is downsized, and it is possible to prevent the occurrence of unevenness of the developer. Moreover, it is possible to arrange the agitation roller laterally within the developer tank, and the development device can be miniaturized, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a developing device showing one embodiment of the present invention;
FIG. 2 is a perspective view of the first and second stirring rollers, FIG. 3 is a diagram showing the developer stirring performance in the axial direction of the roller, and FIG. 4 is a diagram showing the developer stirring performance in the rotational direction of the roller. 1: Developing tank, 2: Developing roller, 3: First stirring roller, 4
:Second stirring roller, ■, :Developing roller rotation speed, V3:
First stirring roller rotation speed, V4: second stirring roller rotation speed. Applicant Sharp Corporation

Claims (1)

[Claims] In the developing tank, a developing roller, a first stirring roller that stirs the toner supplied to the developing tank with the developer and conveys the mixture to the developing roller side, and a first stirring roller arranged between the developing roller and the first stirring roller. A second stirring roller is rotatably provided, and the rotational speed of each roller is set such that the second stirring roller is set to be smaller than the developing roller, and the first stirring roller is set to be faster than the developing roller. A developing device.