JPH06194953A - Image forming device using recovered toner - Google Patents

Abstract

PURPOSE:To prevent soiling of peripheral devices as a result of scattering of toner and to prevent the entire device from being made large by returning developer, removed by a cleaning device used for removing the residual developer from an image carrier, to a second development part. CONSTITUTION:Residual toner on the photoreceptor 12 after transfer is recovered by the cleaning device 16 and carried, via a recovered-toner transport pipe 30, to the second development part 14b arranged upstream from a first development part 14a. Therefore, the first development part 14a contains only fresh toner, and the second development part 14b contains only the recovered toner. The toner sensor 22 of the second development part 14b outputs a signal indicating that an amount of the recovered toner has reached the prescribed amount; thereafter, when a printing operation is not carried out, a control part starts the image forming device as usual, electrifies the photosensitive body, carries out solid development with the development device switched to the second development part 14b, attaches the toner to paper and ejects the paper out of the device.

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 for developing a toner such as a laser printer, a copying machine, a facsimile, etc. More specifically, the toner collected by a cleaning device is processed and discarded or reused. The present invention relates to an image forming apparatus used.

[0002]

2. Description of the Related Art An apparatus for forming an image using so-called fresh toner, which is externally supplied to a toner replenisher in a developing device of an image forming apparatus, is classified as a small machine. In the case of using a process cartridge, the toner remaining on the photoconductor is often cleaned by a cleaning member such as a cleaning brush or a cleaning blade, and is collected and discarded as powder.

At this time, since the collected toner occupies a large volume in the apparatus relative to the weight, the recovery container is likely to fill up relatively quickly. It is a system that only stores collected toner. However, in recent years BAM
As represented by regulations and the like, environmental problems are being highlighted, and even in a small machine using a process cartridge, the collected toner accumulates, for example, about 25 to 30 kg while exchanging only the toner replenisher part. Until now, it is required to use the same process cartridge.

However, simply increasing the size of the collection container makes it extremely difficult to handle in practice, and the size of the image forming apparatus as a whole increases, resulting in an increase in cost. In addition, when discarding the collected toner, the toner may scatter and contaminate the human body and peripheral devices, leaving a problem in operability.

Therefore, for example, Japanese Patent Application Laid-Open No. 61-149981 proposes that the toner collected in the collecting container is heated and softened by the heat transfer means provided in the collecting container mounting portion to be fused and condensed. There is. Further, the collected toner is liquefied with a solvent, and these methods are used to prevent the collected toner from scattering and increase the collected amount by reducing the volume of the collected toner.

However, even with these methods, there is no change in the method of accumulating the recovered toner in the cartridge, and while the life of the parts of other members is extended,
There is a limit in effectively using each member while suppressing an increase in size. Therefore, it is possible to discharge the collected toner out of the cartridge.
Even if the external tank system is adopted, toner is scattered at the joint portion when the container is replaced.

On the other hand, in response to the demand for resource saving, it has been considered for some time to use all the fresh toner in the image forming apparatus. After the development, the toner remaining on the photoconductor is collected by a cleaning device and then returned to the toner replenisher without being discarded.

In such a toner collecting method, however, the collected toner is supplied onto the fresh toner in the replenishing device, and therefore, the collected toner and the fresh toner form respective layers and are deposited. It was necessary to equip the replenishing device with a stirrer to homogenize the toner replenished to the developing device. Therefore, in such an image forming apparatus, a space for installing the stirrer must be secured around the replenishing device, and the image forming apparatus must be increased in size.

Therefore, for example, in Japanese Patent Publication No. 3-77517, it is proposed that the toner collected by the cleaning device is directly fed under pressure into the fresh toner in the toner replenishing device. Since the collected toner is diffused into the fresh toner by the force of direct pressure feeding, no special agitating means is required, and therefore the image forming apparatus can be downsized.

However, in such a conventional toner collecting method, since the collected toner contains paper powder,
In a two-component system having a large gap with the photoconductor, this is not a serious problem, but in a one-component system having a small gap, paper dust clogging occurs at various places and the image quality deteriorates. Therefore, the present invention has been made in view of such a problem in the processing of collected toner, and an object of the present invention is to provide an image forming apparatus that satisfies the demand for resource saving while solving the problems associated with the processing of collected toner. There is.

[0011]

The present invention solves this problem by
At least one first developing section for developing with a developer, and a cleaning device for removing the residual developer from the image carrier,
The problem is solved by an image forming apparatus including a second developing unit that stores only the residual developer and a transport and collection device that returns the developer removed by the cleaning device to the second developing unit.

It is preferable if the second developing section operates according to the amount of toner contained.

Alternatively, it is preferable that the second developing section is activated each time a predetermined number of prints is processed.

Further, at least one developing device for developing with the developer, a cleaning device for removing the residual developer from the image bearing member, and a conveying and collecting device for returning the developer removed by the cleaning device to the developing device. The above problem is also solved by an image forming apparatus provided with a filter means provided in the developer collecting path.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments based on the drawings.

First, in FIG. 1, a lower structure 10b and an upper structure 10a attached to the lower structure 10b by means of a shaft 11 so as to be freely opened and closed.
The photoconductor 12 is arranged in the center of the apparatus main body 10 composed of and, and the charging device 13, the developing unit 14, the transfer device 15, and the cleaning device 16 are arranged around the photoconductor 12 in that order in the rotation direction shown by the arrow. It An optical writing unit 18, which is also one of the electrophotographic process units, is arranged below the electrophotographic process units, and a paper feed cassette 19 is arranged on the upper right side of the electrophotographic process units. .

From the paper feed cassette 19 to the paper feed roller 20
The paper 25 fed by the registration roller pair 21
Then, the sheet is conveyed to the upper side of the belt photosensitive member 12 at a timing. The photoconductor 12 is rotationally driven counterclockwise as viewed in the figure by the rotation of the photoconductor drive shaft, and at that time, the surface of the photoconductor 12 is uniformly charged by the charging device 13. Then, the photoconductor 12 is irradiated with the laser light from the optical writing means 18.
An electrostatic latent image is formed on it. This latent image is developed by the developing device 14
When it passes through, the toner makes a visible image, and this visible image is transferred to the lower surface of the paper 25 conveyed to the upper side of the photoconductor 12 under the action of the transfer roller 15. The transferred visible image on the sheet is conveyed and fixed between the fixing roller and the pressure roller of the fixing device 17. And the fixing device 1
The sheet 25 exiting from No. 7 is further conveyed to the sheet discharge section by the sheet discharge roller 24 and is stacked on the sheet discharge tray.

In this embodiment, the optical writing means 18 is used.
Is arranged below the base cover 29 of the apparatus main body.
The base cover 29 is located at the bottom of the apparatus main body, connects a pair of facing side covers, and is formed integrally or separately with them. Most of the above-mentioned parts are directly or indirectly supported by the base cover 29 and the side cover.

Next, the cleaning device 16 and the developing device 1
The details of the relationship with 4 will be described with reference to FIG.

The transfer residual toner remaining on the photoconductor 12 after the transfer is collected by the cleaning device 16.

The toner collected in the cleaning device 16 is conveyed through the collected toner transfer pipe 30 to the second developing section 14b arranged at the upstream position of the first developing section 14a containing only fresh toner.

Only fresh toner is stored in the first developing section 14a, and only collected toner is stored in the second developing section 14b, which are used separately.

The process of adhering the toner to the transfer paper in the second developing section 14b is the same as the normal image forming process, and the switching of the developing section is performed by switching between the first developing roller 32 and the first developing roller 32 as shown in FIG. This is possible by moving the support member 34 connecting to the second developing roller 33 by turning on / off the solenoid 35.

The timing of switching to the second developing unit 14b is performed when the toner sensor 22 provided in the second developing unit detects that the amount of the collected toner stored exceeds a predetermined amount. .

The operation is as follows. Second developing unit 1
After the toner sensor 22 of 4b outputs a signal notifying that the stored toner has reached a predetermined amount, a control unit (not shown) activates the image forming apparatus normally while the printing operation is not performed. In addition to charging the photoconductor, the developing device is switched to the second developing unit, and then solid development is performed to attach the toner to the sheet and discharge the sheet.

In the present embodiment, the switching to the second developing section is detected by the toner sensor. For example, in order to carry out the collecting toner adhesion process for 5 sheets for 500 sheets, It may be set in advance so that the two developing sections are activated to perform solid development and discharge. The number of sheets required for the collected toner discharge process varies depending on the usage status of the user, and thus may be appropriately adjusted.

In the present embodiment, in short, the collected toner accumulated in the main body of the apparatus is attached to the transfer paper and is discharged to the outside of the apparatus.

An embodiment of another configuration will be described.

The toner collected in the cleaning device 16 is conveyed and collected to the developing device 14 via the collected toner transfer pipe as in the case shown in FIG. In addition, a filter device is provided.

As shown in FIG. 4, the waste toner conveyed from the cleaning device 16 through the recovered toner transfer pipe 30 is temporarily stored in the filter device 37 and passes through the filter 38 mounted in the filter 37. As a result, only the collected toner, which is screened from paper dust and the like and has no impurities, is further conveyed to the developing device 14. In order to prevent clogging of the filter, it is preferable to provide a device for vibrating the filter. In addition, it is more preferable to have a removable structure so that only the filter can be easily replaced.

Furthermore, since the collected toner is a toner that has been used once, its characteristics are slightly different from those of the fresh toner. For example, since the charging ability is inferior, it is preferable to add a carrier excellent in charging ability to maintain the quality of the formed image. From this point, the above two embodiments are combined to include a first developing unit that stores only fresh toner and a second developing unit with a filter that collects only collected toner, and switch both developing units as appropriate. Alternatively, image formation may be performed.

[0032]

According to the image forming apparatus of the present invention, at least one first developing section for developing with the developer, a cleaning device for removing the residual developer from the image carrier, and only the residual developer are provided. Since the second developing unit for accommodating and the conveying and collecting device for returning the developer removed by the cleaning device to the second developing unit are provided, the collected toner having inferior characteristics is discharged to the outside of the apparatus in the same process as the image formation. Therefore, it is possible to prevent contamination of peripheral devices and the like due to toner scattering, and it is possible to prevent the size of the entire apparatus from increasing.

In the image forming apparatus according to the second or third aspect, the second developing section operates depending on the amount of toner contained or operates every time a predetermined number of prints is processed. The discharge can be performed automatically, the effect of the image forming apparatus according to the first aspect can be reliably obtained, and the operation is not troublesome.

In the image forming apparatus of claim 4, at least one developing device for developing with a developer, a cleaning device for removing the residual developer from the image carrier, and a developing device for removing the developer removed by the cleaning device. Since it is equipped with a transport / recovery device for returning to the device and a filter means provided in the developer recovery path, it is possible to remove paper dust and the like from the recovered toner, and it is possible to apply it even to a one-component developing device. The life of cartridges can be extended.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram of an image forming apparatus according to the present invention.

FIG. 2 is a schematic view showing an embodiment of the present invention in which a connection state between a cleaning device and a developing device is emphasized.

FIG. 3 is a schematic diagram showing a configuration for switching between a first developing unit and a second developing unit.

FIG. 4 is a partial schematic diagram emphasizing a connection state between a cleaning device and a developing device according to another embodiment of the configuration.

[Explanation of symbols]

 12 Photoreceptor 14 Developing Device 16 Cleaning Device 22 Toner Sensor 30 Collected Toner Transfer Pipe

Claims (4)

[Claims] 1. At least one first developing section for developing with a developer, a cleaning device for removing the residual developer from the image carrier, a second developing section for accommodating only the residual developer, and a cleaning device. The developer removed by the second
An image forming apparatus provided with a transport / collection device for returning to a developing unit. 2. The image forming apparatus according to claim 1, wherein the second developing unit operates according to an amount of contained toner. 3. The image forming apparatus according to claim 1, wherein the second developing unit is activated each time a predetermined number of prints is processed. 4. At least one developing device for developing with a developer, a cleaning device for removing the residual developer from the image carrier, and a conveying and collecting device for returning the developer removed by the cleaning device to the developing device. An image forming apparatus provided with a filter unit provided in a developer collecting path.