JPH01134479A - Developing device - Google Patents

Abstract

PURPOSE:To execute a satisfactory development by providing a first carrying means on the upper part of a developer supply means and providing a second carrying means for carrying a developer in a second direction being reverse to a first direction on the lower part of said means. CONSTITUTION:Since a feed screw 20 is provided on the upper part of a supply roller 18, a toner (a) drops downward by gravity, therefore, the toner (a) can be delivered efficiently to the supply roller 18. Also, with respect to a control plate 24, by making the width of a rear part R narrower than that of a front part F, the quantity of the toner (a) controlled by the control pate 24 becomes smaller in the rear part R. Accordingly, the toner (a) of the rear part R on the feed screw 20 is delivered efficiently to the supply roller 18, the toner (a) does not collect in the rear part R, the toner circulates satisfactorily, and a toner quantity detecting sensor executes a normal detection, therefore, it does not occur that an excessive toner (a)is supplied into a developing device 4 from a hopper. In such a way, the toner (a) layer being in a uniform state can be formed on a developing roller 10, and a satisfactory development can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a developing device that performs development using, for example, a non-magnetic component developer.

(Prior Art) Recently, in image forming apparatuses such as electrophotographic devices and electrostatic recording devices, electrostatic latent images formed on photoreceptors, dielectric materials, etc. are visualized using non-magnetic component coloring agents. A developing device has been developed. This type of developing device is disclosed in Japanese Patent Application No. 62-11, for example.
It is described in 8311@ gazette.

(Problems to be Solved by the Invention) In the conventional device described above, the first conveyance means and the second conveyance means are in substantially horizontal positions. The developer is sufficiently agitated and charged by circulation between these re-conveying means. however,
It is difficult to transfer the developer from the first conveyance means to the second conveyance means, and the developer accumulates at the end of the first conveyance means in the developing device, reducing the developer circulation efficiency. If the circulation efficiency of the developer decreases, there is a risk that an excessive amount of new developer will be supplied to the first conveying means. However, this newly supplied developer is uncharged and has poor flight properties to the developer carrier. On the other hand, since the developer accumulated at the terminal end is electrically charged, it has good flying properties. Therefore, according to the above-mentioned conventional technology, there is a fear that uneven development may occur due to the difference in the flying properties of the developer within the developing device.

The present invention has been made based on the above-mentioned problems, and an object of the present invention is to provide a developing device capable of performing good-quality development.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a first transport means for transporting the developer in a first direction above the developer supply means. A developing agent is provided below the first conveying means.
A second conveying means for conveying in a second direction opposite to the direction of is provided.

(Function) With the above configuration, the developer excessively transported by the first transporting means is transferred to the second transporting means located below the first transporting means.
It becomes easier to be delivered to the conveyance means.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a developing device that is an embodiment of the present invention, FIG. 2 is a partially cutaway plan sectional view of FIG. 1, and FIG. 3 is an external perspective view of the casing of FIG. , FIG. 4 shows a perspective view of the exterior of FIG. 1. First, the configuration of a developing device according to an embodiment of the present invention will be explained.

Quiet? A developing device main body 4 is arranged around the photosensitive drum 2 that holds the ff latent image. The developing device main body 4 is provided with a developer storage means (container) 6 for storing non-magnetic component toner (developer) a. A developing roller (developer carrier) 10 that supports the toner a on its periphery and faces the photosensitive drum 2 is exposed and provided in the opening 8 of the storage portion 6 . The developing roller 10 is made of stainless steel with an outer diameter of 30111 Ill, for example.
The surface was mirror-finished and then roughened to 4.8n+mRZ by sandblasting. A layer of toner is formed on the developing roller 10 and charged by friction, for example, to a thickness of 0°1.
An elastic blade (developing layer forming means) 12 made of stainless steel No. 5111111 is provided. This elastic blade 1
The free ends of the rollers 2 are disposed to face the rotational direction of the developing roller 10 in the drawing, and the tips are pressed against the developing roller 10 so as not to hit the developing roller 10.

Further, the fixed end of this elastic blade 12 is connected to a holder 14.
is held in

Further, the toner a is placed below the opening 8 in contact with the developing roller 10.
A collection blade 16 lined with, for example, a cushion material is provided for collecting.

A supply roller (developing roller) that supplies toner a to the developing roller 10 on the circumferential surface between the elastic blade 12 and the collection blade 16 on the developing roller 10, and also scrapes off residual toner a that is not used from the developing roller 10. agent supply means)
18 are provided.

The outer periphery of this supply row 518 is made of a soft material such as polyester polyurethane foam and is made porous with single cells.

A feed screw 20 is provided above the supply roller 18 to transport the toner a in the storage portion 6 in a first direction while stirring it. The above-mentioned first direction is from the front part F (the terminal end of the feed screw 20) to the rear part R (the end of the feed screw 20).
0).

A return screw 22 is provided below the feed screw 20 at a position of the supply roller 18 facing the developing roller 10 to transport the toner a in the second direction while agitating the toner a in the container 6. The second direction is opposite to the first direction, and is a direction from the rear portion R to the front 'rAF.

A developer control means (control plate) 24 that is parallel to the feed screw 20, extends downward from above the inner wall surface of the developing device, and has a cross-sectional shape extending toward the feed screw 20, and controls the toner a. is provided. This control plate 24 is wider at the front part F and wider at the rear part R.
The width becomes narrower as you move towards the end.

As shown in the external perspective view of FIG. 4, a pair of positioning rollers 28 are provided at both ends outside the developing device 4, and are provided coaxially with the axis of the developing roller 10. The developing roller 10 contacts both ends of the circumferential surface of the photosensitive drum 2 to maintain a constant distance between the photosensitive drum 2 and the developing roller 10.

Further, a toner reservoir 30 is provided at one end outside the developing device 4 to temporarily hold the toner a. Return screw 22
The discharged toner a is once stored in this toner reservoir 30, and then sent to the storage section 6 again by the feed screw 20. This toner reservoir 30 includes a toner mm detection sensor (developer amount detection means) 32 that detects the amount of toner a.
is provided. Toner a is replenished from the hopper 36 through the replenishment port 34 in accordance with the detection result of the toner spot detection sensor 32 .

Next, the operation of the present device configured as above will be explained.

The toner a supplied from the toner reservoir 30 is developed when the feed screw 20 rotates in the direction of arrow C in the figure! While being conveyed to the first field R of the storage section 6 in the A storage 4, it is supplied to the supply roller 18.

Since the feed screw 20 is located above the supply roller 18, the toner a is easily transferred by gravity.

Further, since the control plate 24 has a wider width at the front portion F than at the rear portion R, the front portion F can more easily receive the 1-ner a. Therefore, the toner a can be uniformly supplied from the feed screw 20 to the supply roller 18.

Next, the toner a is supplied to the phenomenon roller 10 by rotating the supply roller 18 in the direction of arrow B in the figure. By rotating the developing roller 10 in the direction of the arrow in the figure, the elastic blade 12 controls the hanging of the toner a supplied from the supply roller 18, and the toner a is transferred to the developing roller 510.
Between a! A uniform layer is formed on the developing roller 10 by frictional charging.

This layered toner a is opposed to the electrostatic latent image previously formed on the photoreceptor drum 2 as the developing roller 10 rotates in the direction of the arrow in the figure, and the electric field of this electrostatic latent image A bias electric field from a bias power source (not shown) connected to the developing roller 10 causes the electrostatic latent image to move in a circular motion to develop the electrostatic latent image.

Toner a remaining on the developing roller 10 without being subjected to development
is the recovery blade 16. It passes through the supply roller 18 and is collected into the storage section 6 . Next, this toner a is transferred to the return screw 22
is conveyed to the front part F by rotating in the direction of the arrow in the figure, and is discharged into the toner reservoir 30. The toner a once stored in the toner reservoir 30 is sent out to the feed screw 20 again.

According to the above configuration, since the feed screw 20 is provided above the supply roller 18, the toner a falls down due to gravity, so that the feed screw 20 is placed above the supply roller 18.
Hetner a can be delivered efficiently. Also, by making the width of the rear mR of the control plate 24 narrower than that of the front part F, the amount of toner a controlled (received) by the control plate 24 is smaller in the rear part R, so that The toner a in the rear portion R is efficiently delivered to the supply roller 18, and the toner a does not accumulate in the rear portion R, resulting in good toner circulation. When the circulation efficiency of the toner a is good, the toner mm detection sensor 32 performs normal detection, so that excess toner a is not supplied from the hopper into the developing device 4. Therefore, since the toner a in the developing device 4 is in the same state, it is possible to form a layer of toner a in a uniform state on the developing roller 10.

Further, since the control plate 24 has the above-described shape, the most of the toner a received by the control plate 24 is large in the front part F where there is a large amount of toner a on the feed screw 20, and the toner a is small. Since the amount of toner a is small in the rear portion R where it is present, the toner a can be uniformly supplied to the supply roller 18.

The supply roller 18 to which the toner a is evenly supplied
Accordingly, the image can be developed on the photoreceptor 2 in a good condition.

In this embodiment, a developing device using a non-magnetic component developer has been described, but modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As explained above, according to the present invention, by providing the first conveyance means above the developer supply means, the developer is transported to the first conveyance means.
Since the developer does not accumulate at the end of the conveying means and the circulation efficiency of the developer is improved, it is possible to form a layer of developer uniformly on the developer supply means, and as a result, it is possible to perform good development. equipment can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a developing device showing an embodiment of the present invention, FIG. 2 is a partially cutaway plan sectional view of the developing device shown in FIG. 1, and FIG. 3 is a cross-sectional view of the developing device shown in FIG. 1. FIG. M4, an external perspective view of the casing of the apparatus, is an external perspective view of the developing device shown in FIG. 1. 4... Developing device 6... Accommodating section (developer accommodating means) 10... Developing roller (developer carrying means) 12... Elastic blade (developing layer forming means) 18... Supply roller (
developer supply means) 20... feeding screw (first conveying means) 22... return screw (second conveying means) 24
...control board (developer control board)

Claims (2)

[Claims] (1) a developer accommodating means for accommodating the developer; a developer carrying means for carrying the developer in the developer accommodating means; a developer supplying means for supplying the developer to the developer carrying means; a developer layer forming means for forming the developer carrying means layer using the developer supplied by the developer supply means; a second conveying means provided below the first conveying means and conveying the developer in the developer accommodating means in a second direction opposite to the first direction; and a developer control means for controlling developer supplied from the first transport means to the developer supply means. (2) The developing device according to claim 1, wherein the developer control plate controls the developer by having different lengths on the left and right sides in the longitudinal direction.