JPH0453987A - Developing device - Google Patents

Abstract

PURPOSE:To eliminate the clogging of developer in a developing area and to accomplish stable development by providing a shielding plate between a developing roller except a 1st developing roller and a supply roller. CONSTITUTION:The shielding plate 15 is provided between the supply roller 8 and the 2nd developing roller 4. The plate 15 is formed of non-magnetic aluminum and synthetic resin, for instance. Therefore, the developer 12 which drops without being supplied to the 1st developing roller 1 in an area Y2 drops on the plate 15 and is guided by the plate 15 to be collected in a supply part 13. Therefore, the developer 12 is prevented from being directly supplied to the 2nd roller 4 from the roller 8. Thus, the clogging of the developer 12 is prevented form occurring in an area X2 and the stable development is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a developing device for an electrophotographic copying machine, printer, etc. using a powder developer.

(Prior Art) Conventionally, the developing device shown in FIG. 2 has been proposed.

This developing device B includes a first developing device located on the side of the photoreceptor 100.
It includes a developing roller 1, a second developing roller 4, and a supply roller 8 facing the first developing roller 1 at the top. These rollers 1, 4.8 each have a fixed magnetic body 2. 5. 9 and its surroundings with arrows m2゜m3. It consists of a sleeve 3, 6.10 which rotates in the direction of magnet body 2. 5. A magnetic pole is provided on the outer periphery of 9 as shown in the figure.

The developer 12 is stored in the supply section 13, and the developer 12 is stored in the bucket 1.
4 and supplied to the supply roller 8 in area Y. The developer] 2 supplied to the supply roller 8 is held on the outer periphery of the sleeve 10 by the magnetic force of the magnet 9, and
The toner is conveyed in the direction of the arrow m1 as the toner rotates, and after being regulated by the regulating plate 11, it is supplied to the first developing roller 1 in the area Y.

The developer 12 supplied to the first developing roller 1 is held on the outer periphery of the sleeve 3 by the magnetic force of the magnet body 2, is conveyed in the force direction of arrow m as the sleeve 3 rotates, is regulated by the regulating plate 7, and then exposed to light. First development area X1 facing body 100
The electrostatic latent image formed on the outer peripheral surface of the photoreceptor 100 is developed.

The developer that has passed through the first development area X1 is supplied to the second development roller 4 in an area Y3 where the development rollers 1 and 4 face each other.

Next, the developer supplied to the second developing roller 4 is transferred to the magnet body 5.
It is held on the outer periphery of the sleeve 6 by the magnetic force of , and is conveyed in the direction of arrow m3 as the sleeve 6 rotates, and after reproducing the electrostatic latent image on the photoreceptor in the second development area x2, the outer periphery of the sleeve is transferred to the area Y4. It falls from the surface and is collected by the supply section 13.

(Problem to be Solved by the Invention) However, in the developing device B, not all of the developer conveyed to the area Y by the supply roller 8 is supplied to the first developing roller 1. , area Y without being supplied to the first developing roller 1.

may be directly supplied to the second developing roller 4.

In this case, there is a problem in that the amount of developer 12 transported to the second development area X2 increases, and the second development area X is clogged with developer, making development impossible.

(Means for Solving the Problems) The present invention has been made to solve the above problems,
As described above, the supply roller (8) is connected to the first developing roller (1) located at one end of the plurality of developing rollers (1, 4).
), the developer (12) is sequentially delivered to adjacent developing rollers (4), and then developed. A supply roller (8) is provided between the other developing roller (4) and the supply roller (8).
A shielding plate (15) is provided to prevent the developer (12) from being directly supplied from the developer.

(Function) According to the above configuration, the first developing roller (1) is not supplied from the supply roller (8) and the other developing roller (
The developer (12) that has fallen toward the developing roller (4) is blocked by the shielding plate (15) and is not supplied to the other developing roller (4).

(Example) The developing device having the above structure will be described in detail with reference to the example shown in FIG.

In this developing device A, a supply roller 8 and a second developing roller 4 are provided.
A shielding plate 15 is provided between the two. The rest of the configuration is the same as that of the conventional developing device B, and the same parts are given the same reference numerals and explanations will be omitted.

The shielding plate 15 is made of, for example, non-magnetic aluminum or synthetic resin. Further, the shielding plate [5 is inclined at approximately 45 degrees, and the upper end thereof is the outer peripheral part of the first developing roller 1, and the magnetic pole S of the same polarity in the magnet body 2 and the magnetic pole S,
Approximately in the middle area between the two, a gear knob of approximately Q, 5mm in diameter is placed opposite.

Furthermore, a cap of at least about 3 mm is secured between the supply roller 8 and the supply roller 8.

According to the above configuration, the developer 12 is not supplied to the first developing roller 1 in the region Y (the fallen developer 12 falls onto the shielding plate 15, is guided by the shielding plate 15, and is collected in the supply section 13). Therefore, the developer 12 is not directly supplied from the supply roller 8 to the second developing roller 4.
Development area X.

Since the developer 12 is not supplied in excess of the amount required for the region X, the developer I2 will not be clogged in the region X.

Note that if the surface of the shielding plate 15 is coated with Teflon, the developer 12 will fall smoothly without being deposited.

Alternatively, a groove (not shown) may be provided on the surface of the shielding plate 15 along the falling direction, and the developer 12 may fall along this groove.

On the other hand, the developer 12 conveyed by the second developing roller 4
The developer 12 separates from the developing roller 4 in the region Y4, but the separated developer 12 is blocked by the shielding plate 15 and is not directly supplied to the bucket 14, so that it is reliably supplied to the supply section 1.
It is mixed with the developer 12 of No. 3. Therefore, the developer 12 that has lost toner during development is not supplied for development again in that state.

In the above description, the present invention is applied to a developing device A having two developing rollers 1 and 4. However, the present invention may be applied to a developing device having one or more developing rollers below the developing roller 4. In this case, a plurality of shielding plates may be provided or the shielding plate 15 may be extended.

(Effects of the Invention) As is clear from the above description, according to the developing device according to the present invention, developer is not directly supplied to the second and third developing rollers from the supply roller, so that The amount of developer conveyed to the developing area facing the developing roller or photoreceptor remains constant.

Therefore, the developing area is not clogged with developer, and stable development is performed.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a developing device according to the present invention, and FIG. 2 is a partial sectional view of a conventional developing device. AB: Developing device, 4: Developing roller, 8: Supply roller, 15: Shielding plate, 100: Photoreceptor. Patent Applicant Minolta Camera Co., Ltd. Agent Patent Attorney Haka Aoyama Haka18 Figure 2

Claims (1)

[Claims] (1) A plurality of developing rollers arranged on the side of the photoreceptor;
A supply roller is provided opposite to a first development roller located at one end of the development rollers, and the developer supplied from the supply roller to the first development roller is sequentially transferred to an adjacent development roller for development. A developing device that performs the following: A shielding plate is provided between the supply roller and a developing roller other than the first developing roller.