JPH07120106B2 - Development device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement of a developing device provided in an image forming apparatus such as an electronic copying apparatus.

(Prior Art) Generally, in a developing device in an image forming apparatus such as an electronic copying apparatus, a developing device for visualizing an electrostatic latent image formed on a photoconductor which is an image bearing member, for example, a two-component Alternatively, a magnetic one-component developer is known.

However, in the above-mentioned two-component development processing means, it is necessary to accurately control the concentration ratio of the toner as a developer and the carrier, while in the magnetic one-component development processing means, the toner contains a magnetic substance. Therefore, in addition to the disadvantages such as difficulty in colorization, any developing processing means requires a magnet roller as a developing roller that is a developer carrying member, which is very costly. It is very expensive.

Therefore, as a means for solving the above-mentioned problems, a developing processing means using a non-magnetic one-component developer has recently been proposed.

In such a developing device, that is, a non-magnetic one-component developing device, as shown in FIG. 7, a developer carrying member is provided on the inner bottom portion of the hopper 1 which is a containing means containing the non-magnetic toner T. An agitating roller 2 is provided, and by the rotating action of the agitating roller 2, the toner T is supplied from the supply port 3 formed on the lower side surface of the hopper 1 to the developing roller 4 which is a developer carrying member, and the developing roller is also provided. An elastic blade (hereinafter referred to as a coating blade) 5 serving as a thin film forming member is brought into contact with the outer periphery of 4 to develop the toner T passing through the contact portion with the developing roller 4 as a thin film layer having a thickness of 30 μm. While being attached to the roller 4, the electrostatic latent image on the photoconductor A, which is an image carrier formed by closely adjoining the developing roller 4 with a gap G, is developed.

By the way, as the photoconductor A, the one having a negative polarity is used, and therefore, the one having a positive charging property such that the charged amount of the coated toner is about +12 μC / g is used.
The gap G between the photoconductor A and the developing roller 4 is set to, for example, 250 μm, the photoconductor potential is −500 V, and the developing roller 4 has a frequency of 2 KHz and an effective value of 670 V AC voltage and −200 V. A superposition voltage with the DC voltage of is applied.

Such a developing method basically uses a high-resistance one-component toner, and the toner is charged by frictional charging between the toner and the developing roller 4 and the coating blade 5, and the toner is conveyed. Also, due to the electrostatic attraction between the toner and the developing roller 4, the toner rotates as the developing roller 4 rotates, and in this case, there is no need for two-component development or magnetic conveyance such as magnetic one component. Development with high resistance non-magnetic toner can be realized with a very simple structure, which is very advantageous in terms of cost and is most suitable for colorization.

(Problems to be Solved by the Invention) However, in the above-described conventional structure, the toner T in the hopper 1 is likely to be excessively supplied from the supply port 3 to the developing roller 4 side. ,
When the excess toner stays in the space 7 surrounded by the partition wall member 6 and the coating blade 5 between the developing roller 4 which is the partition wall of the hopper 1, and the excessive toner stays excessively in such a space 7, the toner is caused by the pressure. There is a problem that the toner layer thickness on the developing roller and the amount of charge tend to become unstable, as well as causing aggregation or increasing the driving torque of the developing device.

The present invention has been made under the above circumstances, and an object thereof is to make it possible to reliably prevent toner aggregation due to excess toner or increase in driving torque of a developing device. To provide.

[Structure of the Invention] (Means for Solving Problems) In order to solve the above problems, the present invention accommodates a non-magnetic one-component developer and has a supply port for supplying the developer. A developer accommodating means, a developing roller rotatably provided in a predetermined direction facing the image carrier on which the latent image is formed, carrying the developer and carrying the developer, and developing the latent image; Provided near the mouth so as to be in contact with the developing roller and rotatable in the same direction as the rotating direction of the developing roller,
A supply roller for supplying the developer housed in the housing means to the developing roller from the supply port, and a developer provided in contact with the developing roller and supplied to the developing roller, A partitioning wall member that has a coating blade that forms a layer and a regulation member that is provided in contact with the supply roller and that regulates the developer supply amount, and that partitions the supply port of the accommodating means and the supply roller. , The internal pressure of the developer formed in the partition wall member, the developer is excessively supplied to the developing roller, and the developer accumulated in the space formed by the coating blade and the partition wall member on the supply roller is A structure having a mesh-shaped opening for moving the developer from the space portion to the containing means when the internal pressure of the developer contained in the containing means becomes higher. One in which the.

(Operation) That is, according to the present invention, with the above configuration,
Since the opening is formed in the partition wall member between the developing device main body and the developing roller, the internal pressure of the developer excessively supplied from the supply port of the developing device main body to the developing roller side and staying therein is the developing device main body. When the internal pressure of the developer inside becomes higher than the internal pressure of the developer, the excess developer accumulated on the side of the developing roller can flow into the inside of the developing device main body through the opening of the partition wall member, so that the internal pressure of the excess developer increases. As a result, it is possible to reliably prevent the developer from agglomerating, reduce the driving torque of the developing device, and constantly stabilize the developer layer thickness and charge amount on the developing roller. It is possible to let

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the drawings shown in FIGS. 1 to 6. In the illustrated embodiment according to the present invention, the same parts as those of the conventional developing device shown in FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted.

That is, the present invention, as shown in FIG.
The partition wall member 6 between the partition wall member 6 and the developing roller 4 is provided with an opening member 10 so that the space 7 surrounded by the coating blade 5 and the inside of the hopper 1 are communicated with each other. The form of the opening 11 of the opening member 10 is the second
As shown in the drawing, the toner is formed in a mesh shape, whereby excessive toner T is excessively supplied to the space 7 and the internal pressure thereof is the toner (non-magnetic one-component toner) T in the hopper 1.
When the internal pressure becomes higher than the internal pressure, the excess toner T in the space 7 is moved into the hopper 1.

By the way, the shape of the opening 11 of the opening member 10 is not limited to the mesh shape as shown in FIG. 2 but may be a large number of round holes as shown in FIG. It is conceivable that a large number of vertically elongated holes are formed as shown in FIG. 2B, or a large number of horizontally elongated holes are formed as shown in FIG. 3C. Is optional.

Further, FIG. 4 shows a second embodiment of the developing device according to the present invention, in which a developer supplying roller 20 as a supplying means made of urethane material is arranged between the stirring roller 2 and the developing roller 4. The present invention is applied to a structure,
The developer supplying device 20 supplies the toner T in the hopper 1 from the supply port 3 to the developing roller 4 side while contacting the developing roller 4 or rotating in the vicinity thereof.

Further, FIG. 5 shows a third embodiment of the developing device according to the present invention, and like the developing device in the second embodiment, in particular, a regulating member 21 for regulating the toner supply amount to the supply port 3 of the hopper 1. The present invention is applied to a device having a structure in which

Furthermore, FIG. 6 shows a fourth embodiment of the developing device according to the present invention, which has a structure in which a brush-shaped elastic roller 30 is used as the developer supply roller in the second embodiment. The present invention is applied to.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[Advantages of the Invention] As is apparent from the above description, according to the present invention, the developing device main body, the developing roller to which the developer contained in the developing device main body is supplied, the developing roller and the developing device. In a developing device having a partition wall member disposed between the developing device main body and the developing device main body, since an opening is formed in the partition wall member, excessive supply is made from the supply port of the developing device main body to the developing roller side. When the internal pressure of the accumulated developer becomes higher than the internal pressure of the developer inside the developing device main body, the excessive developer accumulated on the developing roller side can flow into the inside of the developing device main body through the opening of the partition wall member. Therefore, the internal pressure of the excess developer does not increase, and thus it is possible to reliably prevent the developer from agglomerating, and it is possible to reduce the driving torque of the developing device, and it is possible to reduce the torque on the developing roller. Developer layer It is possible to provide a developing device which is excellent in cost and can always stabilize the thickness and the charge amount.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a developing device according to the present invention, FIG. 2 is an enlarged explanatory view of an opening member which is also mounted on a partition wall member, and FIG. 3 (a) (b) ( (C) is an enlarged explanatory view showing another embodiment of the opening form of the opening member which is also mounted on the partition wall member, and FIGS. 4 to 6 are second, third and fourth parts of the developing device according to the present invention. FIG. 7 is a schematic sectional view showing a fourth embodiment, and FIG. 7 is a schematic sectional view of a conventional developing device. 1 ... Developing device main body (hopper), 2 ... Developer transport member (stirring roller), 3 ... Supply port, 4 ... Developing roller, 5
...... Elastic blade, 6 ... Partition wall member, 7 ... Space, 10 ... Opening member, 11 ... Open hole, A ... Image carrier (photoreceptor), T ... Developer.

Claims (1)

[Claims] 1. A non-magnetic one-component developer is contained, and
A developer accommodating means having a supply port for supplying a developer and a rotatably provided in a predetermined direction facing an image carrier on which a latent image is formed, and carrying and carrying the developer, A developing roller that develops the latent image, and a developer that is provided in the vicinity of the supply port in contact with the developing roller and is rotatable in the same direction as the rotation direction of the developing roller, and that is stored in the storage unit. A supply roller for supplying the developing roller from a supply port; a coating blade provided in contact with the developing roller to form a developer layer by the developer supplied onto the developing roller; and the supply roller. A partition wall member that is provided in contact with the developer and that regulates the developer supply amount, and that partitions the space between the supply port of the accommodating means and the supply roller; and the partition wall member, roller The developer is excessively supplied, and the internal pressure of the developer accumulated in the space formed by the coating blade and the partition wall member on the supply roller is higher than the internal pressure of the developer stored in the storage means. And a mesh-shaped opening for moving the developer from the space to the containing means when the developing device becomes empty.