JP3450589B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an analog or digital copying machine, a facsimile or a printer, and more particularly to an electrophotographic image forming apparatus for forming an image by using a two-component developer composed of a carrier and a toner. It is about.

[0002]

2. Description of the Related Art Conventionally, a two-component developer composed of carrier particles and toner particles triboelectrically adhered to the carrier particles has been widely used as being suitable for obtaining a high quality copy image. When development is performed using such a two-component developer, the toner content of the developer is consumed as the electrostatic latent image is visualized, so it is necessary to replenish new toner as appropriate. Generally, the toner concentration in the developer in the developing device is usually 2 to 10% for each device type and developer type, and is controlled within ± 2%. When the toner concentration in the developing device decreases and it becomes necessary to replenish the toner, the toner to be replenished is directly sent to the developing device and mixed in the developing device.

[0003]

When the toner is replenished directly from the toner container to the developing device, the toner density in the developing device is greatly varied immediately after the replenishment. That is, in the vicinity of the portion where the toner is supplied, the toner concentration is considerably high before the stirring and mixing.
In the vicinity of the developing sleeve, the density becomes lower than the proper density. Generally, toner supply is performed at intervals of paper feeding timing, but as the speed of the image forming apparatus becomes higher, the interval becomes shorter, and it is necessary to supply the required amount of toner at the shortened intervals. A uniform toner density must be achieved in a short time.

However, in the case of a high-speed machine, the amount of toner consumed per unit time increases, and a large amount of toner is replenished in a short interval, so that the unevenness of toner density in the developing device becomes even greater. In the conventional stirring and mixing apparatus, it has become difficult to prevent uneven density in image formation.

Therefore, it is an object of the present invention to provide an image forming apparatus capable of replenishing necessary toner in a short time while suppressing unevenness of toner density in a developing device with a simple structure.

[0006]

According to the present invention, there is provided the above object, an image carrier, a developing device with a stirring means for developing an electrostatic latent image of the image carrier by a two-component developer, and the developing device. A developer having a function of supplying a developer and toner to the developing device and recovering a part of the developer from the developing device, and can store the developer and the toner to be supplied and the developer to be recovered in an integrated container. In an image forming apparatus having an agent / toner container mounting portion and a conveying means for conveying the developer or toner between the integrated container and the developing device, a partition plate which can be opened and closed between the conveying means and the developing device. In the state where the partition plate is closed, unused toner is replenished from the developer / toner container mounting portion into the conveying means, and the conveying means is operated to stir and mix the developer. High toner content The image agent is made to stay in advance, and when the toner concentration in the developing device decreases, the partition plate is opened and the conveying means and the agitating means in the developing device are operated so that the developer having a large toner content rate is developed. To solve the problem.

When the toner is replenished to the developing device, the carrying means operates so as to continuously execute the first mode for carrying the developer into the developing device and the second mode for carrying out the developer from the developing device. Is preferable.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on the embodiments shown in the drawings. A developing device 2 equipped with the toner / developer replenishing device 1 is shown in FIGS. The toner / developer supply device 1 includes a powder container 3 for storing toner and a two-component developer composed of toner and carrier, a toner and a developer discharged from the container to the developing device 2, and a developing device 2 The toner / developer transport device 4 circulates the developer derived from.

Although the powder container 3 is apparently one container, in reality, in this embodiment, the first powder container member 11, the second powder container member 12 and the powder mixing container member are used. Are integrally connected, and the toner and the developer are supplied on a common end plane. The detailed configuration of the first powder container member 11 and the second powder container member 12 is disclosed, for example, in the specification of Japanese Patent Application No. 7-171157.
By the action of the spiral protrusion attached to the inner peripheral surface of each container member in accordance with the rotation of the integrated container in the A direction and the B direction,
Different powders contained in the first powder container member 11 and the second powder container member 12 are separately discharged. Depending on the supply timing and the like, it is also possible to discharge simultaneously in the same rotation. Generally, unused developer is stored in the smaller first powder container 11 and unused toner is stored in the larger second powder container 12. A powder mixing container member is disclosed, for example, in the specification of Japanese Patent Application No. 7-262948, and includes a first powder container member 11 and a second powder container member.
A container for mixing toner and developer discharged from the powder container member 12, which is a toner / developer transport device 4 after mixing.
And a developer for recovering the developer from the toner / developer carrying device 4. In the present invention, this powder mixing container member can be omitted. The details of the powder container members 11 and 12 and the powder mixing container member are not essential to the present invention, and will not be further described here.

As shown in FIG. 2, the toner / developer carrying device 4 has a first carrying screw 21 and a second carrying screw 22 built therein, and is fed from the developing device 2 by the first carrying screw 21. The developer is delivered to the second carrying screw 22 on the front side of the drawing, and returned to the developing device 2 by the second carrying screw 22.

A partition plate is provided between the toner / developer carrying device 4 and the developing device 2 (not shown). The partition plate is adapted to be opened and closed by driving means such as a motor and a solenoid. When the partition plate is closed, new toner or developer does not enter the developing device 2 but circulates in the toner / developer carrying device 4. This state is shown in FIG. 5, which is a schematic plan view of the toner / developer transporting device 4 as viewed from above. That is, while the partition plate 30 is closed, the unused toner is supplied from the container to the toner / developer conveying device 4, and the conveying screws 21 and 22 are driven to agitate only the developer in the device in advance. Mix. At this time, since the developer already exists in the toner / developer transporting device 4, only unused toner is replenished to the toner / developer transporting device 4. Is adjusted so that the developer has a high concentration. FIG. 7 shows an operation flow when replenishing toner to the developing device in this embodiment. In conjunction with the partition plate being closed,
It is also possible to stop the first conveying screw 21 and the second conveying screw 22 of the toner / developer conveying device 4 except at one time before and after the opening and closing (for the stirring and mixing operation).
When the toner concentration inside the developing device decreases, the partition plate is opened and the high-concentration developer in the toner / developer carrying device 4 is supplied to the developing device. Since this high-concentration developer is in a state in which the toner is sufficiently dispersed in the developer, it is possible to reduce uneven density when being supplied into the developing device. At this time, the first conveying screw 21 takes in the developer at the time of the next toner replenishment into the toner / developer conveying device 4. By such a procedure, the toner and the developer, which are difficult to mix, can be mixed in advance with stirring, and the uneven density when supplying to the developing device can be suppressed.

As shown in FIG. 4, the toner / developer carrying device 4 of another structure shown in FIG. 3 is a uniaxial type carrying device containing only the first carrying screw 21. The developer discharged from the developing device 2 is taken into the toner / developer carrying device 4 by the first carrying screw 21.

Unused toner is replenished to the developer taken into the toner / developer carrying device 4. By rotating the first conveying screw forward and backward with the partition plate closed,
The taken developer and toner are mixed and stirred. This state is shown in FIG. 6, which is a schematic plan view of the toner / developer conveying device 4 as seen from above. Further, FIG. 8 shows an operation flow when toner is supplied to the developing device in the present embodiment. The density adjustment and the supply timing to the developing device are the same as in the case of the above-mentioned biaxial type conveying device. After supplying the high-concentration developer from the transport device 4 to the developing device 2, the first transport screw 21 is rotated in the loading direction, and the developer at the next toner replenishment is loaded into the toner / developer transport device 4. By doing this,
The toner and the developer can be agitated and mixed before being supplied to the developing device.

[0014]

According to the present invention, an openable / closable partition plate is provided between the transporting means for storing the replenishing developer / toner and the developing device, and the partitioning plate is closed in the transporting means. In addition, the unused toner is replenished from the developer / toner container mounting portion and the conveying means is operated to stir and mix so that the developer having a toner content higher than that of the developer in the developing device stays in advance. When replenishing toner to the apparatus, the partition plate is opened, and the conveying means and the stirring means in the developing device are operated to supply the developer having a large toner content to the developing device. It is possible to suppress unevenness in density during replenishment by supplying the toner to the developing device after mixing with the above.
Further, since the conveying means also serves as the stirring area, the structure is not complicated.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a positional relationship between a toner / developer supply device and a developing device according to the present invention.

FIG. 2 is a schematic view in which a toner / developer transport device in FIG. 1 is partially opened.

FIG. 3 is a schematic perspective view showing a positional relationship between a toner / developer supply device including a uniaxial conveying screw and a developing device.

FIG. 4 is a schematic view in which the toner / developer transport device in FIG. 3 is partially opened.

FIG. 5 is a schematic plan view illustrating the conveyance of the developer or the toner in the toner / developer supply device of FIG.

FIG. 6 is a schematic plan view illustrating the conveyance of a developer or toner in the toner / developer supply device of FIG.

FIG. 7 is an operation flow when toner is replenished in an embodiment including a biaxial type conveying screw.

FIG. 8 is an operation flow at the time of toner replenishment in an embodiment including a uniaxial type conveying screw.

[Explanation of symbols]

1 Toner / developer supply device 2 Development device 4 Toner / Developer Transport Device 11 First powder container 12 Second powder container 21 1st conveying screw 22 Second conveying screw

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Naofumi Shoji 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-5-297717 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/08 112 G03G 15/08 507

Claims (2)

(57) [Claims] 1. An image carrier, a developing device with stirring means for developing an electrostatic latent image of the image carrier with a two-component developer, and a developer and toner are supplied to the developing device to develop the image. A developer / toner container mounting portion that has a function of recovering a part of the developer from the apparatus and can store the developer and the toner to be supplied and the developer to be recovered in an integrated container, and the integrated container and the development. An image forming apparatus having a conveying unit that conveys a developer or a toner to and from the apparatus, wherein a partition plate that can be opened and closed is provided between the conveying unit and the developing device, and the conveying unit is configured in a state where the partition plate is closed. In the means, unused toner is replenished from the developer / toner container mounting portion, and the conveying means is operated to stir and mix, so that the developer having a toner content ratio higher than that of the developer in the developing device stays in advance. , To developing device When the toner is replenished, the partition plate is opened and the conveying means and the stirring means in the developing device are operated to supply the developer having a large toner content to the developing device. 2. When the toner concentration in the developing device decreases, the carrying means continuously executes a first mode for carrying the developer into the developing device and a second mode for carrying out the developer from the developing device. The image forming apparatus according to claim 1, wherein the image forming apparatus operates.