JPH0756577B2 - Rotating multicolor developing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rotary multicolor developing device.

(Prior Art) In the field of color electrophotography, there is known a developing device which is disposed close to an electrostatic latent image carrier and sequentially supplies several types of toner to the electrostatic latent image to perform multicolor development.

In this type of conventional developing device, a plurality of developing devices having a function of developing with toners having different colors are sequentially rotated to supply toners of a desired color to the electrostatic latent image to form a color image.

However, in the above-described conventionally known developing device, there is no mechanism for replenishing the toner even if the developing device is deficient in toner, and when the toner is exhausted, it is so-called disposable. Therefore, the toner is not always used on average in each developing device, and there is a possibility that residual color toner remains, which is uneconomical.

For example, as a means for replenishing toner, it is easy to replenish toner of different colors to each developing device using the same replenishment path. However, if this is carried out, color mixing and replenishment of toner of each color In that case, secondary problems such as toner scattering may occur.

(Purpose) Therefore, an object of the present invention is to improve the economical efficiency by replenishing toner without causing color mixing, and at the same time, a rotary multicolor developing device capable of uniformly distributing the replenishment toner in the developing chamber. To provide.

(Structure) In order to achieve the above object, the present invention is directed to a developing device which is disposed in proximity to an electrostatic latent image carrier and which sequentially supplies several types of toner to an electrostatic latent image to perform multicolor development. A cylinder having a plurality of independent developing chambers formed for each color in the circumferential direction, a toner replenishing port provided at each developing chamber at a different position on the outer peripheral surface of the cylinder, and each color for each color. Toner storage chambers for storing toner, toner outlets arranged in communication with the respective toner storage chambers so as to be opposed to the toner supply ports in accordance with the rotation of the cylindrical body, and electrostatic latent images from the respective development chambers. Each of the toner replenishing ports and the toner outlets is provided with an opening / closing means, and each of the developing chambers has a toner feeding amount per rotation toward the shaft end. Equipped with a screw stirring means to reduce It is characterized by that.

Hereinafter, a specific description will be given based on an embodiment of the present invention.

In the following embodiment, a rotary multicolor developing device for a color electrophotographic copying machine, which develops using four-color one-component toner, will be described.

In FIG. 1 and FIG. 2, reference numeral 1 indicates a rotatable drum-shaped cylindrical body, inside of which four independent developing chambers 1C, 1C are provided.
M, 1Y, 1B are formed. Each of these developing chambers extends in the axial direction of the cylinder 1, and the size thereof corresponds to the longitudinal size of the photosensitive drum 20 which is close to and opposed to the cylinder 1. Further, it is assumed that the developing chamber 1C contains cyan, the developing chamber 1M contains magenta, the toner chamber 1Y contains yellow, and the developing chamber 1B contains black.

For example, in the developing chamber 1B, a rectangular toner replenishing port 2B is formed at a portion corresponding to the peripheral surface of the cylindrical body 1 and is located at the rightmost end in the axial direction of the cylindrical body. A lid 3B for opening and closing is provided. The lid 3B is fitted inside a guide groove (not shown) inside the tubular body 1 and is slidable.
The lid 3B is opened and closed by a rack and pinion mechanism driven by a motor or a mechanism using a solenoid. Thus, the lid 3C and the drive mechanism are collectively referred to as a toner replenishing port opening / closing means.

The toner replenishing port 2B is located substantially in the center of the developing chamber 1B in the rotational direction of the cylinder 1, and the cylinder 1 is located farther than the toner replenishing port 2B.
A developing means including a developing roller 4B, a sponge roller 5B, a sliding contact member 6B and the like is provided in the vicinity of the partition wall on the downstream side in the rotation direction of. A part of the developing roller 4B is exposed from the peripheral surface of the cylindrical body 1 so that the developing roller 4B can closely face the photosensitive drum 20 at a required rotation position of the cylindrical body. Further, in the vicinity of the partition wall on the upstream side in the rotation direction of the cylindrical body 1, a screw 7B as a stirring means for uniformly distributing the toner in the axial direction of the cylindrical body is provided. As shown in FIG. 3, the screw 7B has the opposite winding direction at the portion corresponding to the toner supply port 2B.
Moreover, the pitch is set to become finer toward the shaft end.

If the screw pitch is the same in the axial direction as shown in FIG. 4, the amount of replenished toner varies depending on the axial position. For this reason, the toner amount in the axial direction is different, which causes image unevenness. In this embodiment, the one-component development is carried out, but the two-component development has a further bad influence.

However, as shown in this example, if the screw pitch is set so that the lateral feed amount is smaller as it is closer to both ends in the axial direction, that is, closer to the side plate, and the feed amount is larger as it is closer to the toner supply port 2B, the inside of the developing chamber 1B The toner can be evenly distributed on the surface. Then, the unevenness of the image can be prevented by uniformly and evenly dispersing the replenishment toner in the axial direction.

The above is the main configuration of the developing chamber 1B. Development room 1B
The above-mentioned various members in 1) are exactly the same in other developing chambers. Therefore, the reference numerals indicating the constituent members of the other developing chambers will be indicated by the reference numerals of the developing chamber 1B in which the letters B are replaced by C, M and Y without changing the numerals. Here, the toner replenishing ports are displaced at a constant interval in the axial direction of reference numeral 1. That is, the toner supply port 2C is located closer to the center than the toner supply port 2B, the toner supply port 2M is located on the left end side, and the toner supply port 2Y is located on the leftmost end side. This deviation of each toner supply port is to correspond to each of the toner storage chambers 8B, 8C, 8M, 8Y described later.

A toner container 8 containing four types of toners of cyan, magenta, yellow, and black is fixedly installed in the color electrophotographic apparatus main body obliquely above the cylindrical body 1. The toner container 8 has four toner storage chambers arranged in the axial direction of the cylinder 1.
8B, 8C, 8Y and toner outlets communicating with these toner storage chambers, respectively.

For example, as shown in FIG. 2, the toner supply port 2B is the toner outlet.
The screw 7B is located below the toner replenishing roller 2B at the specific rotation position of the cylinder 1 when it coincides with 80B, and the developing roller 4C is closest to the photosensitive drum 20 and is electrostatically charged. The latent image is developed with cyan toner. At the same time, the lid 3B is opened and the valve 8 at the outlet 80B is opened at the same time.
00B is opened, and the black toner stored in the toner storage chamber 8B is supplied to the developing chamber 1B. The supplied black toner falls on the partition wall and the screw 7B, is transported in the axial direction according to the rotation of the screw 7B, and is uniformly distributed.

Thus, when the supply of black toner is completed, the valve 800B is closed and the lid 3B is also closed. When the development with the cyan toner is completed, the cylinder 1 rotates in the direction of the arrow, and the toner supply port
2C stops at a position matching the toner outlet communicating with the toner storage chamber 8C. This stop position is also the position where the developing roller 4M is closest to the photosensitive drum 20.

Then, the electrostatic latent image is developed with magenta toner by the developing roller 4M. The cyan toner in the toner storage chamber 8C is replenished in the developing chamber 1C.

According to the above process, the replenishment and the development will be sequentially performed for other toners.

The toner replenishment ports 2B, 2C, 2M, 2Y are closed tightly by the lids 3B, 3C, 3M, 3Y etc. except when the toner is replenished, so that the toner will not scatter or flow out. Has been done. The same applies to the valves provided at the toner outlets of the toner storage chambers 8B, 8C, 8M, and 8Y. Further, the sliding contact members 6B, 6C, 6M and 6Y that are in sliding contact with the developing roller have a sealing function at the same time as frictionally charging the toner. The sponge rollers 5B, 5C, 5M, 5Y have an auxiliary function of adhering toner to the developing rollers.

As described above, in this example, toners from the independent toner containers are replenished to the independent developing chambers through the dedicated toner outlets, so that color mixing does not occur at the time of replenishing the toners.

Further, since the toner container 8 is fixed to the main body of the color electrophotographic apparatus, it is easy to replenish the toner in the toner chambers 8B, 8C, 8M and 8Y.

Further, since the toner is replenished stably and continuously, the amount of toner stored in each developing chamber can be reduced,
There is an advantage that the developing device can be downsized.

(Advantages of the Invention) According to the present invention, it is advantageous that the toner can be replenished without causing color mixing, so that the economical efficiency can be improved and the replenished toner can be uniformly distributed in the developing chamber.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a rotary multicolor developing device according to the present invention, FIG. 2 is a cross-sectional view of the same as above, and FIG. 3 is a relational position between a position where the winding direction of each screw is reversed and each toner supply port. FIG. 4 is a developed view for explaining the distribution of the toner replenishment amount when the screw pitch is uniform. 1 ... Cylinder, 2B, 2C, 2M, 2Y ... Toner supply port, 3B, 3C, 3M,
3Y ... Lid, 4B, 4C, 4M, 4Y ... Developing roller, 7B, 7C, 7M, 7Y ...
…screw.

Claims (1)

[Claims] 1. A developing device, which is disposed in the vicinity of an electrostatic latent image carrier and which sequentially supplies several kinds of toner to an electrostatic latent image to perform multicolor development, is formed for each color in a circumferential direction. A cylindrical body having a plurality of independent developing chambers, a toner replenishing port provided on the outer peripheral surface of the cylindrical body at a different position for each developing chamber, and a toner accommodating chamber for accommodating toner for each color. A toner outlet communicating with each of the toner accommodating chambers so as to face the toner replenishing port in accordance with the rotation of the cylinder, and a developing unit for supplying toner from each developing chamber to the electrostatic latent image. Each of the toner supply ports and each of the toner outlets is provided with an opening / closing means, and each of these developing chambers has a stirring means by a screw that reduces the toner feed amount per rotation as it approaches the shaft end. Times characterized by being equipped Transfer type multicolor developing device.