JPH0518765Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a developing device for an electrophotographic copying machine.

[Conventional technology]

Various developing means for electrophotographic copying machines have been developed and put into practical use, one of which is a two-component system consisting of charged toner particles and magnetic carrier particles that electrostatically attract and transport the toner particles. There is a magnetic brush developing means that causes spikes of developer made of the above to stand up using a magnetic field and brings the developer into contact with an electrostatic latent image formed on a photoreceptor to form a toner image on the latent image. A chute is used as a means for collecting surplus developer from the developing roll that conveys the developer to the photoconductor side and mixing the developer and toner. As another means, an auger is used to rotate the developer collected as a surplus in a direction to mix it with the toner.

[Problem that the invention attempts to solve]

In the developing device as described above, when considering the circulation state of the developer, it is found that the toner cannot be sufficiently supplied.
There is a problem that the copy density is not stable, and there is also a backflow of developer, and the above problems are even more pronounced in developing devices having a small relative distance.

[Means and actions for solving problems]

The present invention has been developed in consideration of the above-mentioned problems, and it is possible to smoothly collect surplus developer from the developing roll, and to develop the product after properly mixing and stirring the surplus developer with a high-concentration developer. The purpose of the present invention is to provide a developing device for an electrophotographic copying machine that is capable of supplying toner to the roll side to obtain a stable copy density. In a developing device of an electrophotographic copying machine that uses a developer to develop a latent image on a photoreceptor using a magnetic brush development method using a developer roll, excess developer from the developer roll is placed in a stirring chamber on the rear side of the developer roll. In addition to providing a surplus developer receiving chamber partitioned by a surplus developer receiving plate, a developing chamber facing the developing roll 1, and a toner supply chamber 3c communicating with the toner chamber,
A merging chamber communicating with one side end of these chambers is provided,
A transport auger with the merging chamber side facing upstream in the transport direction is installed in the surplus developer receiving chamber, a transport auger with the merging chamber side facing downstream in the transport direction is installed in the developing chamber, and a transport auger with the merging chamber side facing downstream in the transport direction is installed in the toner supply chamber. A conveyance auger is provided on the downstream side, and the upstream side of the toner supply chamber in the conveyance direction by the conveyance auger communicates with the toner chamber, and the downstream side of the excess developer receiving chamber in the conveyance direction by the conveyance auger is connected to the developing chamber and the toner supply chamber. The developing roll 1 is connected to the upstream side of the conveying direction by each conveying auger, and the developing roll 1 is connected to the surplus developer receiving plate.
The structure includes a chute for receiving the excess developer trimmed by the developer roll, and the excess developer from the developing roll is received by the chute of the excess developer receiving plate and stored in the excess developer receiving chamber, where it is collected. The toner is sent together with the developer from the merging chamber by the provided transport auger, and is sent to the upstream side in the transport direction of each transport auger in the developing chamber and toner supply chamber by the downstream side in the transport direction. In the toner supply chamber, new toner is supplied from the toner chamber along with the developer from the surplus developer receiving chamber to the upstream side in the direction of conveyance by these conveyance augers, and this is conveyed to the merging chamber while being stirred by the conveyance augers. . Further, in the developing chamber, while the developer supplied from the surplus developer receiving chamber is conveyed to the merging chamber side by the conveying auger, it comes into contact with the developing roll to perform development.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

In the figure, 1 is a developing roll provided facing the photoreceptor 2, 1a is a box supporting this developing roll 1, and this box 1a includes a stirring chamber 3 on the rear side of the developing roll 1, and a toner There is a room 4. A trimmer bar 5 is provided above the developing roll 1 and facing the upstream side in the rotational direction thereof. The agitation chamber 3 has a surplus developer receiving chamber 3a, a developing chamber 3b facing the developing roll 1, and a toner supply chamber 3 communicating with the toner chamber 4 through a surplus developer receiving plate 6 and a partition 7.
It is divided into three chambers 3a, 3b, 3
c are communicated with each other through a merging chamber 3d formed at one end thereof. Conveying augers 8, 9, and 10 are provided in each of the chambers 3a, 3b, and 3c in parallel, with one end of each facing toward the merging chamber 3. A conveying auger 11 is also provided within the toner chamber 4.

The conveyance direction of each of the augers 8, to 11 is within the developing chamber 3b, and within the toner supply chamber 3c.
10 is directed towards the merging chamber 3d, and the conveying auger inside the surplus developer receiving chamber 3a and the toner chamber 4 is directed towards the merging chamber 3.
It is designed to be transported in the d direction and the opposite direction, respectively.

The upstream side of the toner supply chamber 3c in the conveyance direction by the conveyance auger 10 is a toner chamber 4 and a surplus developer receiving chamber 3.
a through openings 12 and 13, respectively. Further, the upstream side of the developing chamber 3b in the conveying direction by the conveying auger 9 is communicated with an opening 14 in the surplus developer receiving chamber 3a.

The surplus developer receiving plate 6 constituting the surplus developer receiving chamber 3a includes a chute 6a for receiving surplus developer from the trimmer bar 5, and a pipe portion 6b along the conveying auger.
It is made up of.

In the above configuration, the developing roll 1 and each of the conveyance augers 8, - 11 are rotationally driven during the developing operation. As the developing roll 1 rotates, the developer raised on the surface of the developing roll 1 is applied to the photoreceptor 1.
The latent image on the photoreceptor 1 is developed. At this time, excess developer on the surface of the developing roll 1 is trimmed by a trimmer bar 5 and received by a chute 6a of an excess developer receiving plate 6. The development of the developing roll 1 is performed using a developer in a developing chamber 3b.

Next, the movement of toner and developer due to the rotation of the four conveyance augers 8, 11 will be explained.

First, due to the rotation of the transport auger 11 in the toner chamber 4, the toner in the toner chamber 4 is supplied to the upstream side in the transport direction of the transport auger 10 of the toner supply chamber 3c through the opening 12. Also, the surplus developer receiving chamber 3a
A portion of the developer therein is supplied through the opening 13 to the upstream side of the toner supply chamber 3c in the conveyance direction by the conveyance auger 10. Further, most of the remaining surplus developer in the surplus developer receiving chamber 3a is supplied from the opening 14 to the upstream side in the conveyance direction by the conveyance auger 9 of the development chamber 3b.

The toner supplied to the upstream side of the toner supply chamber 3c in the conveyance direction by the conveyance auger 10 is conveyed to the merging chamber 3d by the conveyance auger 10 while being stirred.
On the other hand, the developer in the developing chamber 3b is also conveyed to the merging chamber 3d by the conveying auger 9 thereof. The two developers are then mixed in the merging chamber 3d and conveyed to the excess developer receiving chamber 3a while being stirred by a conveying auger 8 provided there, and from the downstream side of the surplus developer receiving chamber 3a to the developing chamber 3b.
is fed through the opening 14 to the upstream side of the water.

In the developing chamber 3b, a developing action is performed using the developer in which the toner is well mixed through the above-mentioned path. At this time, as the developer in the developing chamber 3b goes downstream in the direction of conveyance by the conveying auger 9, the toner concentration gradually decreases due to consumption due to the above-mentioned developing action. The toner concentration is restored by merging with the developer having a high toner concentration that has been conveyed from the developer.

In the above embodiment, the opening 14 for supplying the developer from the surplus developer receiving chamber 3a to the developing chamber 3b was provided only on the downstream side, but as shown in FIG. A plurality of holes 15 are provided in the longitudinal direction of the pipe portion 6b of the plate 6, and the developer in the surplus developer receiving chamber 3a is also transferred from each hole 15 to the developing chamber 4b.
It may also be supplied to the side.

[Effect of idea]

According to the present invention, surplus developer from the developing roll 1 can be smoothly collected. In particular, according to the present invention, the surplus developer receiving chamber 3a of the stirring chamber 3 and the developing chamber 3
A merging chamber 3d is provided at one side end of the toner supply chamber 3c and the surplus developer receiving chamber 3a, and a conveying auger 8 with the merging chamber 3d side upstream in the conveying direction is provided in the surplus developer receiving chamber 3a, and a merging chamber 3d is provided in the developing chamber 3b. The conveying auger 9 with the downstream side in the conveying direction is further connected to the toner supply chamber 3c in the merging chamber 3.
A conveyance auger 10 with the d side as the downstream side in the conveyance direction is provided, and the conveyance auger 10 of the toner supply chamber 3c
The upstream side of the surplus developer receiving chamber 3a in the conveyance direction by the conveyance auger 8 is connected to the toner chamber 4, and the downstream side of the surplus developer receiving chamber 3a in the conveyance direction by the conveyance auger 8 is connected to the development chamber 3b and the toner supply chamber 3c.
By communicating with the upstream side in the conveyance direction by the respective conveyance augers 9 and 10, the developer whose concentration has become low due to toner consumption while being conveyed through the developing chamber 3b is transferred to the merging chamber at the downstream end thereof. At step 3d, the toner is mixed with the high-concentration developer conveyed from the toner supply chamber 3c, and then conveyed together with the surplus developer while being stirred by the conveyance auger 8 of the surplus developer receiving chamber 3a, and then conveyed again to the development chamber 3b. The developer can be supplied to the upstream side in the conveyance direction by the auger 9, and as a result, the developer in the developing chamber 3b can always maintain a constant concentration state and can always obtain a stable copy density.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a longitudinal sectional view, FIG. 2 is a developed explanatory view, and FIGS. 3 and 4 are parts showing different embodiments of the surplus developer receiving plate. FIG. 1 is a developing roll, 2 is a photoreceptor, 3 is a stirring chamber, 3
3b is a developing chamber, 3c is a toner supply chamber, 4 is a toner chamber, 6 is a surplus developer receiving plate, and 6a is a chute.

Claims (1)

[Scope of utility model registration request] In a developing device of an electrophotographic copying machine that uses a two-component developer consisting of toner and carrier to develop a latent image on a photoreceptor 2 using a magnetic brush development method using a developing roll 1, a stirring chamber on the rear side of the developing roll 1 is used. 3
a surplus developer receiving chamber 3a partitioned by a surplus developer receiving plate 6 for receiving surplus developer from the developing roll 1; and a developing chamber 3b facing the developing roll 1;
A toner supply chamber 3c communicating with the toner chamber 4 is provided, and a merging chamber 3d communicating with one end of these chambers 3a, 3b, 3c is provided, and a merging chamber 3d side is provided in the surplus developer receiving chamber 3a. The conveyance auger 8 is connected to the upstream side in the conveyance direction, and the merging chamber 3 is connected to the developing chamber 3b.
A conveying auger 9 with the d side as the downstream side in the conveying direction and a conveying auger 10 with the merging chamber 3d side as the downstream side in the conveying direction are provided in the toner supply chamber 3c. The upstream side communicates with the toner chamber 4, and the downstream side of the surplus developer receiving chamber 3a in the conveyance direction by the conveyance auger 8 communicates with the upstream side in the conveyance direction by the respective conveyance augers 9 and 10 of the developing chamber 3b and toner supply chamber 3c. The developing device for an electrophotographic copying machine is further characterized in that the surplus developer receiving plate 6 is provided with a chute 6a for receiving surplus developer trimmed from the developing roll 1.