JPH0372381A - Image forming device - Google Patents

Abstract

PURPOSE:To adapt an image forming device to a quick color copying device by connecting the toner reception hole of a developing device in the development position and the toner discharge hole of a hopper corresponding to the developing device. CONSTITUTION:A developing device 4 is provided with developing devices 4Y, 4M, 4C, and 4BK movably, and for example, the developing device 4Y is transported to the fixed development position to develop a body 1 to be devel oped. Hoppers 201Y, 201M, 201C, and 201BK are arranged in certain positions, and a toner reception hole 401Y of the developing device 4Y in the development position and a toner discharge hole 3201Y of the hopper 201Y corresponding to the developing device 4Y are connected in the development position by a toner supply tube 300Y. Consequently, a large capacity of toner is held though the developing device 4 is small-sized, and the reliability of the mechanism is improved even at the time of quick movement because a hopper 200 and the developing device 4 are separated from each other at the time of movement of the device 4. Thus, this device is adapted to the quick color copying device.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention can be suitably used in a developing device of a color recording device that generally constitutes the output section of a color electrophotographic copying machine, a computer, a facsimile machine, etc. It relates to a developer or toner replenishing device (simply referred to as a "toner replenishing device" in the present invention), and in particular, a device in which a plurality of developing devices are mounted on a conveying device and a desired developing device is opposed to the object to be developed, which is a latent image carrier. This invention relates to a toner replenishing device for a developing device that is moved to a position where development is performed.

``Prior Art'' Recently, the demand for color copying has rapidly increased not only in specialized fields but also in general office work, and there is a desire for a color copying machine that can be used not only by professionals but by anyone. Currently, full-color electrophotographic copying machines that utilize electrophotographic technology are generally widely used as color copying machines.

Full-color electrophotographic copying machines still have various problems that need to be solved or improved, but one of them is the ability to visualize electrostatic latent images of each color formed on a developing object, that is, a photoreceptor. In the developing device, the problem lies in the configuration in which toner or developer is supplied to each developing device.

Conventionally, various means have been proposed as developing devices for color electrophotographic copying machines, but they can be broadly classified into two types. One of them is a side-by-side developing device in which multiple developing devices each containing a developer of each color are arranged in parallel along the surface of a photoreceptor.
It is currently being used in large quantities.

In commercially available electrophotographic copying machines, the photoreceptor is usually a cylindrical drum, so the developing units of the developing device are arranged close to the surface of the photoreceptor drum and in parallel along the circumferential direction of the photoreceptor drum. Placed.

The second type is a reciprocating developing device in which a movable stage is provided adjacent to the photoreceptor and is movable in the tangential direction of the photoreceptor, and a plurality of developing units are arranged on this movable stage.

The above-mentioned side-by-side developing device seems to have a simple structure, as it is sufficient to simply arrange developing devices each having a plurality of different color developers in sequence around the photosensitive drum, but in reality, only one developing device is used. While the developing device is in operation, it is necessary to keep the other developing devices inactive, and for this purpose, the rotation of the magnetic brush roller in the developing device must be controlled, or the developing device itself must be removed from the surface of the photosensitive drum. A means for separating them is required, and as a result, the side-by-side developing device is forced to have a complicated structure and complicated operation control.

Furthermore, according to this type of developing device, the diameter of the photosensitive drum inevitably becomes large because a plurality of developing devices are sequentially arranged around the photosensitive drum, so it is extremely difficult to downsize the electrophotographic copying machine. Have difficulty. Furthermore, although the position where the latent image of each color is formed on the photosensitive drum is constant, the developing position of each color by the developing device is different, and therefore the time until the latent image of each color is developed is different. Correction of the time decay of the image is required. Such correction work is not technically simple and complicates the control of the developing device and the copying machine as a whole.

On the other hand, the reciprocating developing device allows only the developing device of the desired color to face the latent image on the photosensitive drum to perform development. This has the advantage that it is possible to reduce the size of the image, and there is no need to correct the time attenuation of latent images of each color.

However, when the concentration of developer in each developing device decreases, it is necessary to automatically replenish toner into the developing device.

Conventionally, in a developing device using a magnetic brush method that uses a two-component developer consisting of toner and a carrier that is magnetic powder, in addition to a developing chamber containing the developer, there is also a developing device in which the developer in the developing chamber is kept at a predetermined concentration or lower. A toner chamber is provided to replenish toner to the developing chamber when the toner is used, and toner for replenishment is stored in the toner chamber.

``Problems to be Solved by the Invention'' The larger the toner chamber, the more replenishment toner can be stored, but naturally the developing device has to be larger, making the entire developing device huge. A large developing device has a large moment of inertia, and it is extremely difficult and practically impossible to drive and control such a device at high speed.

Therefore, it is conceivable to adopt a method in which the toner chamber is normally made small and the toner chamber is replenished as needed via a cartridge-type toner replenisher.

However, when a large number of copies are required, it is necessary to frequently stop the developing device or drive it to the toner replenishment position, insert a toner replenisher into the developing device, and replenish the toner chamber with toner. Ru. Such work is not only extremely tedious work for the operator, but also causes a significant reduction in copying speed.

The above description also applies to a developing device that replenishes developer.

In some cases, the toner discharge port of the hopper and the toner receiver of the developing device are connected to each other so that the toner can be constantly replenished by a conveyance means. However, in this method, as described above, since the developing device is moved at high speed, the conveying means moves rapidly, making it extremely difficult to extend the durability of the connecting portion.

Therefore, the main object of the present invention is to make the developing device smaller and, by extension, the entire reciprocating developing device smaller, capable of holding a large amount of toner, and making it possible to continuously make large numbers of copies. An object of the present invention is to provide an image forming apparatus equipped with a highly reliable toner supply device.

Another object of the present invention is to provide an image forming apparatus equipped with a toner replenishing device that reduces the inertia of the reciprocating developing device by downsizing the developing device and facilitates control.

"Means for Solving the Problems" The present invention provides a developing device which is movably equipped with at least one developing device, and which transfers a desired developing device to a fixed developing position and develops an object to be developed; and at least one hopper disposed at the developing position, and at the developing position, the opening of the toner receiver of the developing device located at the developing position communicates with the toner discharge port of the hopper corresponding to the developing device. It is a device.

"Example" Hereinafter, an example of the present invention will be specifically described based on the drawings.

FIG. 1 is a longitudinal sectional view of a main part of an image forming apparatus for forming a full-color copy image embodying the present invention. In the figure, a photosensitive drum 1 which is an electrostatic latent image carrier, that is, a body to be developed.
rotates in the direction of the arrow shown in the figure, and a charger 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged around it. The document reading device 7 includes a document scanning section 7a.
The exposure device 3 forms a color-separated electrostatic latent image on the photosensitive drum 1 according to a signal from the photoelectric element 7b. Further, the developing device 4 has four developing devices, for example, a yellow developing device 4Y using yellow toner, a magenta developing device 4M using magenta toner, a cyan developing device 4C using cyan toner, and a black developing device 4BK using black toner. . By moving the movable table 100 in the direction of the arrow shown in the figure, each developing device 4Y, 4
M, 4C, and 4BK are transferred to a developing position opposite to the photosensitive drum 1, and a developing operation is performed.

On the other hand, the transfer device 5 includes a dielectric drum 5 having a gripper 5a.
b, and a transfer discharger 5c inside the drum 5b.Similar to conventional copying machines, a full-color image is produced by sequentially transferring color toner onto a transfer material supported on the drum 5b. be done. The transfer material is supplied from the cassette 8 or the manual feed section 9 through the paper feed path 8a or 9a, and the transfer material that has completed the transfer process is separated and conveyed by the separating means 10, fixed by the fixing section 11, and then placed on the tray 1.
It is stored on 2.

Now, the developing device 4 will be explained in more detail.

The movable table 100 on which four developing units are mounted is a rack 101a.
A pinion 101b fixed to the output shaft of a motor M is engaged with the rack 101a. motor(
For example, by driving the stepping motor M, any one of the developing units 4Y, AM, and 40° 4BK can be transferred to the developing position. Developing device 4Y has reached the developing position.

Any one of 4M, 4C, and 4BK is pushed up toward the photosensitive drum 1 by a lifting means (not shown) and becomes ready for development. In the case of this figure, the development position is below the photosensitive drum 1,
The yellow developing device 4Y is in contact with the photosensitive drum 1. For example, when forming a monochromatic or two-color image, the elevating means of the unnecessary developing device is not operated and the developing device is allowed to pass through the developing position while it is spaced apart from the photosensitive drum 1.

Next, a toner replenishing device according to the present invention will be explained.

In this embodiment, as shown in FIG. 2, a toner replenishing device 200 is arranged on the front side of the image forming apparatus in FIG. Each developer 4Y, 4M, 4C.

Yeo-toner hopper 201Y, magenta toner hopper 2oIM, which stores color toner to be replenished to 4BK.
, cyan toner hopper 20IC, black toner hopper 201 BK are fixed to the support frame 202, and the support frame 2
02 is locked at a fixed position on the main body of the image forming apparatus.

A support frame 202 having a rotation center 203 is connected to the developing devices 4Y, 4.
M, 4C.

During maintenance and inspection of the hopper 48, the hopper can be rotated in the direction of arrow A around the rotation center 203, and can be placed at a position where work is easy.

In FIG. 2, the moving direction of the moving table 100 is in the direction of the arrow.

Figure 3 is a plan view showing the toner replenishing device and the developing device;
The figure is a front view of FIG. 3. The toner replenishing device 200 is provided with a toner conveying means 600. The toner conveying means 300 includes a toner supply pipe xooY that can communicate with the yellow toner hopper 201Y, a toner supply pipe 300M that can communicate with the magenta toner hopper 201M, a toner supply pipe 300C that can communicate with the cyan toner hopper 201C, and black toner. Equipped with a toner supply pipe xooBK that can communicate with the hopper 2018K, each toner supply pipe 3
ooY, xooM, 3ooc, and 5ooBK are provided with conveyance means such as screws, and each toner supply pipe 5ooY
Toner outlet provided at each outlet of xooM, 5ooc, and 5aoBK! to IY, 501Mj01C.

3a 1BK is placed facing downward on line 2 perpendicular to the moving direction C of the developing device 4. Line 2 passes near the developing position. Further, each of the developing units 4 has a toner receptacle opening 40.
0 is set. Developing devices 4Y, 4M, 4 in the developing device
If there are C and 4BK, toner discharge hole 301Yε toner receiver is opening 400Y.

Toner discharge hole 301Mε Toner receiver opening 400M, )
The toner discharge port 301C and the toner receiver port 400C are aligned, and the toner discharge port so 1BK and the toner receiver port 400BK are aligned.

As mentioned above, when any of the developing units 4Y, 4M, 4C, and 4BK reaches the developing position, it is pushed up in the direction of the photosensitive drum by an unillustrated elevating means (in FIGS. 1 and 3, the developing unit 4Y ). As a result, one of the toner sockets 400 of the corresponding toner discharge port 501 is brought into communication.

According to the above embodiment, the developing units 4Y and 4M move.

4C, 4BK toner receiver is 400Y, 400M, 40
0C.

Toner hopper zo1Y corresponding to any of 4008
.

zolM, zotc, 2o [Toner outlet 3 from 3K
By configuring so that any one of oIY, solM, aolc, and aolBK coincidentally communicates with each other at the developing position of developing units 4Y, 4M, 4C, and 4BK, the developing units 4Y, 4M during development can
, 4C, and 4BK can be constantly replenished depending on the usage status. For example, if you replenish a large amount of toner at once, developing units 4Y, 4M, and 4C will be used.

Insufficient agitation with the carrier in 4BK may result in insufficient tribo, causing toner to scatter from developing units 4Y, 4M, AC, and 4BK and smudge the image. In this embodiment, the toner replenishment position is the development position. Therefore, it is possible to gradually replenish toner according to the signal of the developer concentration detector (not shown) of the developer units 4Y, 4M, 4C, and 4BK without moving the position during development. Developing density and tribo can be maintained at all times. Also, developing devices 4Y, 4M, and 4C.

The 4BK toner receiver does not require a conveyance means that always connects the opening 4O0 and the toner discharge port 301, so it can maintain high reliability, and the transfer speed to the developing units 4Y, 4M, 4C, and 48 is fast, and replenishment can be performed frequently. It is also possible to apply this method to high-speed color copying machines.

"Other Embodiments" In FIG. 5, the shapes of the hoppers 201 are the same, and the openings 400 of the toner receivers of the developing units 4Y, 4M, 4C', and 48 are aligned in the same direction as the moving direction of the developing units. It is something. In the state shown in FIG. 5, the developing device 4Y is at the developing position, and the opening 400Y of the toner receiver and the toner discharge port 301Y of the yellow toner hopper 201Y are in communication with each other so that toner can be replenished. When the developing device 4M comes to the developing position, the opening 400M of the toner receiver of the developing device 4M and the toner discharge hole 601M of the magenta toner hopper 201M match, and when the developing device 4C comes to the developing position, the toner receiver of the developing device 4C matches the opening 400M of the toner receiver of the developing device 4M. 40
0C and toner outlet g of cyan toner hopper 2010
When one matches and the developing device 48K comes to the developing position, the toner receiving port 4CIOEK of the developing device 4BK and the toner discharge port 3018K of the black toner hopper 2 o 1BK match.

In the embodiment, a hopper was installed for each developing device so that the toner receptacle of the developing device at the developing position communicated with the toner discharge port of the hopper corresponding to the developing device. It is also effective to provide a hopper and have the same configuration only for the developing devices with a large number of toners, and to replenish the remaining developing devices with toner cartridges.

〔Effect of the invention〕

As explained above, the present invention includes at least one movable developing device, a desired developing device is transported to a fixed developing position, and a developing device for developing an object to be developed is arranged at a fixed position. The image forming apparatus has at least one hopper, and at a developing position, the opening of the toner receiver of the developing device at the developing position communicates with the toner discharge port of the hopper corresponding to the developing device. Depending on the situation.

Even with a small developer I, continuous high-capacity image formation can be continued for a long period of time, and since the hopper and developer are separated when the developer is moved, the mechanism remains stable even when the developer is moved at high speed. It became possible to increase the reliability of This has made it possible to support high-speed color image forming devices.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing the overall configuration of an embodiment of the present invention, FIG. 2 is a perspective view of a hopper and a developing device of the embodiment of the present invention,
5 is a plan view of a hopper and a developing device according to an embodiment of the present invention, FIG. 4 is a front view of FIG. 3, and FIG. 5 is a plan view of another embodiment. 4-・Developing device 200・・Toner hopper 300・
Toner supply pipe 301・◆Toner discharge port 400・・Toner receiver is the opening.

Claims (1)

[Claims] 1. A developing device which is movably equipped with at least one developing device and which transfers a desired developing device to a fixed developing position and develops an object to be developed, and at least one hopper arranged at a fixed position. An image forming apparatus comprising: a toner receptacle of a developing device at a developing position and a toner discharge port of a hopper corresponding to the developing device communicating with each other at a developing position.