JPS60222875A - Developing device - Google Patents

Abstract

PURPOSE:To make a little device small in size and light in weight, and also to make the service life of plural developers uniform by constituting said device so that the diameter of a rotating body is different from each other in accordance with the use frequency of plural developing devices. CONSTITUTION:The outside diameter of a magnet roller 43 of the first developing device 14 for containing developers 42 of blue, red and yellow whose consumption quantity is small is made small, and the diameter of a magnet roller 46 of the second developing device 15 for containing a developer of black whose consumption quantity is large is made large. Accordingly, the device is made small in size and light in weight without deteriorating its copying performance, and the service life of the developers 42, 45 can be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a developing device for performing multicolor development, which is provided in, for example, a copying machine.

[Technical background of the invention and its problems]

As this type of developing device, one shown in FIG. 1, for example, is conventionally known. In other words, the photosensitive drum 1 is a photosensitive drum that can be freely rotated in a circular pattern, and adjacent to the photosensitive drum 1 there are a first and a second photosensitive drum along the direction of rotation.
Developing units 2 and 3 are provided. By the way, normally, in the first developing device 2, for example, red color, which has a low consumption amount,
A second developing device 3 contains developer 4 of blue, yellow, etc.
For example, a black developer 5, which is consumed in a large amount, is stored therein. Further, magnetic rollers 6.7 for supplying developer are provided in the first and second developing devices 2 and 3, respectively.

Therefore, during development, the first or second developing device 2, 3
The magnet rollers 6 and 7 inside are rotated and the photosensitive drum 1
Developers 4 and 5 are supplied to the electrostatic latent image formed thereon to perform multicolor development.

However, in the past, the magnet rollers 6.7 of the first and second developing devices 2, 3 were made to have the same diameter regardless of the consumption amount of developer 4.5, which resulted in an increase in size. There was an inconvenience. , Ma, Magnet roller 6
If the diameter of the photosensitive drum I is large, the circumference of the photosensitive drum I must be increased accordingly, and the diameter of the photosensitive drum 1 must also be large.
Furthermore, the lifespans of the developers 4 and 5 in the first developing device 2, which is used less frequently, and the second developing device 3, which is used more frequently, are long (and vary).

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a developing device that can be made smaller and lighter, and can also equalize the lifespan of a plurality of developers. It is something to do.

[Summary of the invention]

In order to achieve the above object, the present invention is such that the diameter of a rotating body for supplying developer is varied depending on the frequency of use of a plurality of developing devices.

[Embodiments of the invention]

The present invention will be described below with reference to an embodiment shown in FIG. In the figure, reference numeral 11 denotes a main body of the copying machine, and a photosensitive drum 12 is rotatably provided in the center of the main body 11. A charger 13, a first developer 14, a second developer 15, a charger 13, a first developer 14, a second developer 15,
A transfer and peel charger 16, 17 and a cleaning device 18 are provided. Further, a paper feed cassette 19 is provided at the lower part of one side of the main body 11, and sheets P are taken out one by one from this paper feed cassette 19 by the rotation of a paper feed roller 20 and sent to a registration roller 21. It has become. 22 is a paper ejection path, and the paper ejection path 22 includes a conveyor belt 23, a fuser 24,
and a paper discharge roller 25 are provided. Further, a paper ejection tray 26 is provided on the ejection side of the paper ejection roller 25.

Further, an exposure system 30 including a light source 27, a plurality of reflecting mirrors 28, a lens 29, etc. is provided on the upper side of the apparatus main body 11.

Further, on the upper surface of the apparatus main body 1, there is provided a document placing table 3I on which a document is placed.

On the other hand, the first developing device 14 stores in its container 41 a developer 42 of, for example, blue, red, or yellow, which has a small consumption amount, and also has a first developing device as a rotating body that supplies the developer 42.
It is equipped with a magnet roller 43. In addition, the second
The imager 15 stores a black developer 45, which is consumed in a large amount, in a container 44, and is equipped with a second magnet roller 46 as a rotating body. The first developing device 1
The first magnetic roller 43 of No. 4 is connected to the second developing device 1.
The diameter of the second magnet roller 46 of No. 5 is also small,
The first developing device 14 is also smaller in size than the second developing device 15. That is, the first developing device 14 is used for small amount copying, and the second developing device
The developing device 15 is constructed to be suitable for mass copying.

The first and second developing units 14 and 16 are each driven independently, and can be selected and used when copying using selection buttons (not shown) on the operation panel. It looks like this.

During copying, the surface of the photosensitive drum 12 is uniformly charged by the charger 13, and an electrostatic latent image corresponding to the original is formed on this charged surface by the exposure system 3o. Then, this electrostatic latent image is transferred from the first developing device 14 or the second developing device 15 to the magnetic roller 43 or 46.
As the developer 42 or 45 is supplied by the rotation of the developer 42 or 45, the image is visualized and transferred to the paper P supplied from the paper feed cassette 19 in the transfer charger 16. The paper P to which this image has been transferred is placed in a peeling charger 17.
The toner is peeled off from the photosensitive drum 12 and sent to the fixing device 24, where it is fixed and then ejected to a paper ejection tray 26 via a paper ejection roller 25.

As mentioned above, since the diameter of the magnet roller 43 of the first developing device 14, which is used less frequently, is made smaller than the diameter of the magnet roller 46 of the second developing device 15, which is used more frequently, high-speed, high-volume copying performance can be achieved. The device can be downsized without damage, and the life of the developer 42, 45 in the first and second developing units 14 and 15 can be made uniform.

In the above-mentioned embodiment, an example is described in which two developing devices are provided, but the present invention is not limited to this, and a larger number of developing devices may be provided.

It goes without saying that the present invention can be further modified in various ways within the scope of its gist.

〔Effect of the invention〕

As explained above, the present invention changes the diameter of the rotary body depending on the frequency of use of the plurality of developing units, so it is compact without impairing high-speed, large-volume copying performance.

It is possible to reduce the weight and cost, and also has the effect of making the lifespan of the plurality of U agents uniform.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional example, and FIG. 2 is a schematic block diagram showing a copying machine which is an example of the present invention. 14... First developing device (developing device), 15... Second developing device (developing device), 43... First magnet roller (rotating body), 46... Second developing device magnetic roller (rotating body), 42, 45...developer.

Claims (2)

[Claims] (1) In a device that is equipped with a plurality of developing devices, and a rotating body disposed in these developing devices conveys developer and supplies it to the surface to be developed, the amount of developer is adjusted according to the frequency of use of the plurality of developing devices. A developing device characterized by having rotating bodies having different diameters. (2) The developing device 0 according to claim 1, wherein the rotating body is a magnetic roller.