JP2006091325A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of improving agitation of a developer by suppressing unevenness in screw pitch. <P>SOLUTION: The developing device is equipped with a developer carrier 1 which has a plurality of peripherally arranged magnetic poles and carries a developer, 1st and 2nd agitating conveyance means 2 and 3 which agitate the developer in a developer container 109 and carry it toward the developer carrier 1, and a developer-restricting means 5 of restricting the developer on the developer carrier 1 to a designated layer thickness, and has a partition wall 4 between adjacent magnetic poles of the same polarity of the developer carrier 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device that visualizes a latent image as a developer image by applying the developer to a rotatable latent image carrier that carries the latent image, and an image forming apparatus including the developing device.

  FIG. 8 is a cross-sectional view showing a schematic configuration of a conventional developing device provided in an electrophotographic image forming apparatus. The developing device that faces the photoconductor 11 includes a developing roller 1, a first agitation transport screw 2, a second agitation transport screw 3, a developer regulating member 5, and a toner concentration detection means 7. Reference numeral 6 denotes a developer (carrier, toner).

By the way, the developing roller is composed of a rotatable sleeve and a magnetic pole fixedly arranged inside the sleeve. Since the sleeve has a small diameter, the magnetic pole arranged inside the sleeve is an adjacent repulsive magnetic pole (example in FIG. 8). Then, S1 and S3) must be arranged close to each other, and when the developer peeled off by the repulsive magnetic force is immediately pumped up by the developer layer thickness regulating pole, an image with a high image density is obtained. In some cases, uneven density may occur.
In addition, the two-component developer that visualizes the electrostatic latent image on the photosensitive member has a reduced toner concentration due to the consumption of the toner, but it is in a state where it is mixed with a developer having a sufficient toner concentration. When the toner is replenished, the stirrability is not good, the toner density is difficult to stabilize, and density unevenness may occur.
SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device capable of suppressing unevenness on a screw pitch and improving the stirring property of a developer, and an image forming apparatus provided with the developing device.

In order to achieve the above object, the invention described in claim 1 is a developer carrying body having a plurality of magnetic poles arranged in the circumferential direction and carrying the developer, and stirring and developing the developer in the developer container. A first and second agitating and conveying means parallel to the developer carrying body that is conveyed toward the developer carrying body, and a developer regulating means that regulates the developer on the developer carrying body to a predetermined layer thickness, A developing device having a partition between adjacent magnetic poles of the same polarity adjacent to the developer carrying member is the main feature.
According to a second aspect of the present invention, in the developing device of the first aspect, the second agitating / conveying means in which the developer divided by the partition is disposed away from the developer carrying member in the agitating / conveying means. The main feature is a developing device that falls to the side.
The invention according to claim 3 is characterized in that, in the developing device according to claim 2, the developing device in which the developer falls to the upstream side of the second agitating and conveying means.
According to a fourth aspect of the present invention, in the developing device according to the third aspect, the developing device is characterized in that the developer drops by gravity to the upstream side of the second agitating and conveying means.
The invention according to claim 5 is characterized in that, in the developing device of claim 3, the developing device in which the falling developer joins the replenished toner is a main feature.
The invention according to claim 6 is characterized in that, in the developing device according to claim 3, the developing device in which the developer falls to the upstream side of the second agitating / conveying means by the third agitating / conveying means.
The invention according to claim 7 is characterized in that, in the developing device according to claim 6, the developing device is provided with a toner replenishing means upstream of the third stirring and conveying means.
The invention according to claim 8 is characterized in that, in the developing device according to claim 2, the developing device provided with the toner density detecting means is a main feature.
According to a ninth aspect of the present invention, an image forming apparatus equipped with the developing device of the first aspect is the main feature.

  The present invention relates to a developer carrier having a plurality of magnetic poles arranged in the circumferential direction and carrying a developer, and a developer carrier that stirs the developer in a developer container and conveys the developer toward the developer carrier. The first and second agitating / conveying means in parallel with each other, and the developer regulating means for regulating the developer on the developer carrying member to a predetermined layer thickness, and the adjacent magnetic poles of the same polarity adjacent to the developer carrying body. By having a partition in between, the intended purpose can be achieved.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing the configuration of the developing device of Example 1, FIG. 2 is a configuration diagram of the developing device of Example 2 (A view in FIG. 1), FIG. 3 is a B view in FIG. FIG. 5 is a configuration diagram of the developing device of the third embodiment (corresponding to FIG. 3), FIG. 5 is a longitudinal sectional view showing the configuration of the developing device of the fourth embodiment, and FIG. FIG. 7 is a diagram showing the configuration of the developing device of Example 5 (C view in FIG. 5).
A configuration common to the whole will be described. The developing device includes a developer container 10, a developing roller 1 that is a developer carrying member disposed in the photosensitive member-side opening of the developer container 10, and development that regulates the layer thickness of the developer on the surface of the developing roller 1. An agent regulating member 5, a first stirring and conveying screw 2 that is a stirring and conveying means, and a second stirring and conveying screw 3 that is an agitating and conveying means adjacent thereto are provided. The developing roller 1 includes a sleeve rotatably supported and a plurality of magnets (magnetic poles) fixedly disposed in the sleeve, and faces the photoconductor 11.
In Examples 1-5, the partition 4 installed in the shape of a slope between the 1st stirring conveyance screw 2 and the 2nd stirring conveyance screw 3 is arrange | positioned.
Moreover, in Examples 4-6, the 3rd stirring conveyance screw 9 which is a stirring conveyance means is arrange | positioned. In Examples 3, 5, and 6, the toner replenishing means 8 is arranged.

Next, the operation will be described. The developer container 10 is filled with the two-component developer 6, and is agitated and conveyed by the second agitating and conveying screw 3 and the first agitating and conveying screw 2 that are rotatable. Then, the toner is drawn up to the developing roller 1 by the magnet S <b> 3 disposed inside the developing roller 1, and is made a prescribed layer thickness by the developer regulating member 5.
While the developer 6 having a specified layer thickness goes to the magnets N1 and N2, toner is attached to the latent image formed on the photoconductor 11 to form a visible image. Thereafter, the developer 6 applied to the S1 pole is peeled off from the developing roller 1 by the adjacent repulsive pole magnet S3.
In the first embodiment, the developer 6 peeled off by the partition wall 4 disposed between the poles of the magnets S1 and S3 is conveyed to the second stirring and conveying screw 3. Therefore, the developer in the developer container 10 is mixed.
In Example 2 shown in a plane cross-sectional view in FIG. 2 and in a view B in FIG. 3, the developer 6 peeled off from the developing roller 1 by the magnet S3 of the repulsive pole is second as shown by an arrow. To the upstream portion of the agitating and conveying screw 3, where it is mixed with the developer 6 in the developer container 10.
In Example 3 shown in FIG. 4, the toner supplied from the toner replenishing means 8 together with the removed developer 6 falls along the partition wall 4 to the second agitating / conveying screw 3, where it enters the developer container 10. It is mixed with a certain developer 6.
In Example 4 shown in FIG. 5, the developer 6 is conveyed to the second agitating and conveying screw 3 by the third agitating and conveying screw 9 positioned above the second agitating and conveying screw 3.
In the fifth embodiment shown in FIG. 6, the toner replenishing means 8 is arranged upstream of the third stirring and conveying screw 9, and the toner concentration detecting means 7 is arranged upstream of the second stirring and conveying screw 3. The toner is replenished to the developer 6 whose toner density is lowered.
In Example 6 shown in FIG. 7, the toner density detecting means 7 is also arranged downstream of the second stirring and conveying screw 3 and circulates with the developer 6 that has consumed the toner by adhering to the latent image. Detects the difference in toner density with the existing toner.
In the developing device of the present invention, the developer remaining after development is not immediately pumped up to the first agitating and conveying screw 2, but is dropped into the second agitating and conveying screw 3, thereby increasing the agitation time. Since a stable developer can be obtained, high image quality can be achieved.

1 is a configuration diagram of a developing device according to Embodiment 1. FIG. FIG. 3 is a configuration diagram (a view of FIG. 1) of a developing device of Example 2. FIG. 3 is a B view of FIG. 2. FIG. 10 is a configuration diagram (corresponding to FIG. 3) of a developing device according to Embodiment 3. FIG. 10 is a configuration diagram of a developing device according to Embodiment 4. FIG. 10 is a configuration diagram of a developing device according to a fifth exemplary embodiment (view C in FIG. 5). FIG. 10 is a configuration diagram of a developing device according to a fifth exemplary embodiment (view C in FIG. 5). It is a block diagram of the conventional developing device.

Explanation of symbols

1 Development roller (developer carrier)
2 1st stirring conveyance screw (stirring conveyance means)
3 Second stirring and conveying screw (stirring and conveying means)
4 Partition 5 Developer regulating member (Developer regulating means)
10 Developer container

Claims (9)

  A developer carrier comprising a plurality of magnetic poles arranged in the circumferential direction, and a rotatable developing sleeve arranged so as to surround the magnetic poles, and agitating the developer in the developer container and developing the developer carrier First and second agitating and conveying means parallel to the developer carrying member conveyed toward the developer, and developer regulating means for regulating the developer on the developer carrying member to a predetermined layer thickness. A developing device having a partition wall between adjacent magnetic poles of the same polarity.   2. The developing device according to claim 1, wherein the developer divided by the partition wall falls to a second agitating / conveying means disposed at a position away from the developer carrying member in the agitating / conveying means. A developing device.   3. The developing device according to claim 2, wherein the developer falls to the upstream side of the second agitating and conveying means.   4. The developing device according to claim 3, wherein the developer falls by gravity to the upstream side of the second agitating / conveying means.   4. The developing device according to claim 3, wherein the falling developer joins the replenished toner.   4. The developing device according to claim 3, wherein the developer is dropped to the upstream side of the second agitating / conveying means by a third agitating / conveying means.   7. The developing device according to claim 6, further comprising a toner replenishing unit upstream of the third stirring and conveying unit.   3. The developing device according to claim 2, further comprising a toner density detecting unit.   An image forming apparatus comprising the developing device according to claim 1.

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