JPH0450963A - Image forming device - Google Patents

Abstract

PURPOSE:To recover the toner of different developing units without mixing it and to reuse it by operating a cleaning blade corresponding to a desired developing unit and a circulating means when the desired developing unit is selected. CONSTITUTION:When the desired developing unit 15 or 16 is selected, the cleaning blade 17 or 18 corresponding to it and the circulating means are operated. In other words, the toner scratched off by a first blade drops on a toner collecting groove 23, is circulated into the first developing unit 15 through a first toner carrying pipe 25 by a toner carrying coil 25a, and recovered. The toner scratched off by a second blade 18 drops on a second toner collecting groove 24, is circulated into the second developing unit 16 through a second toner carrying pipe 26 by a second blade coil 26a, and recovered. Thus, the toner of the different developing units 15 and 16 is recovered without being mixed and can be reused.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrophotographic image forming apparatus, and more particularly, to an electrophotographic image forming apparatus that is equipped with a plurality of color developing devices and that removes residual toner on a photoreceptor and refluxes it to the developing device. The present invention relates to an image forming apparatus configured as described above.

(Prior Art) An electrophotographic image forming apparatus generally develops an electrostatic latent image formed on a photoreceptor using a developing device, and transfers the resulting developed image onto a transfer member using a transfer means. After that, the toner remaining on the photoconductor is scraped off with a blade in contact with the photoconductor to clean it, and after that, the photoconductor is irradiated with erase light to remove the residual charge, and then it is uniformly charged by a charging means and then charged again. 2. Description of the Related Art An image forming apparatus is also known that is configured to repeat the operation of exposing to light to form an electrostatic latent image, and is equipped with a plurality of developing units to enable color image formation.

On the other hand, in an image forming apparatus equipped with a single developing device,
There is also known a device in which the toner scraped off by the blade is returned to the developing device for recovery and reuse.

(Problem B that the invention seeks to solve) However, in a device equipped with a plurality of developing devices as described above, it is impossible to reuse the toner scraped by the blade because the toner scraped by the blade gets mixed with the toner. The toner is stored in a waste toner box and disposed of. Therefore, it is desired to be able to separately collect and reuse the toner in each developing device.

As described above, an object of the present invention is to provide an image forming apparatus that is equipped with a plurality of developing devices and is capable of reusing toner scraped off by a blade.

(Means for Solving the Problems) In order to achieve the above object, the image forming apparatus of the present invention has a plurality of color developing units installed in parallel, and the image forming apparatus according to the present invention performs separate cleaning in correspondence with each developing unit. Provide a blade,
It is characterized by providing a reflux means for refluxing the toner scraped by each cleaning blade to its corresponding developing device, and a means for switching the cleaning blade and reflux means corresponding to the selected developing device into an operating state. shall be.

(Function) According to the above structure of the present invention, in an image forming apparatus equipped with a plurality of developing devices, when a desired developing device is selected, the cleaning blade and the reflux means corresponding to that developing device are activated. The toner scraped off by the cleaning blade is returned to the developing device, and the toner can be collected and reused without mixing toners from different developing devices.

(Example) Below, an example in which the present invention is applied to a copying machine is shown in Figs.
This will be explained with reference to FIG.

In FIG. 1 showing the overall configuration, reference numeral 1 denotes a document table glass on which a document 2 is placed.The document 2 is illuminated by a light source 3 below the document table glass 1, and the document image is transferred to a convergent light transmission medium. The photoreceptor 5 is configured to be exposed to light through the array 4 . Around the photoconductor 5, a developing section 6, a transfer charger 7, a cleaning device 8, an eraser lamp 9, and a charging charger]0 are arranged in order from the exposure section in the rotational direction of the photoconductor 5. The developed electrostatic latent image is transferred to the developing section 6.
After development, a transfer charger 7 applies an electric field from the back side of the transfer paper to transfer the toner image on the surface of the photoreceptor 5 to the transfer paper, and the toner remaining on the photoreceptor 5 is scraped off by a cleaning device 8. Erase lamp 9 after cleaning
The photoreceptor 5 is irradiated with light to remove residual potential, and then a charger 10 applies a constant electric charge to the surface of the photoreceptor 5.

Further, the transfer paper that is picked up and fed one by one from the paper feed section 11 is supplied to the transfer section by the registration roller 12 in synchronization with the toner image formed on the photoreceptor 5, and the transfer paper is fed to the transfer section by the transfer charger 7. The toner image is transferred onto a transfer paper, the toner image on the transfer paper is fixed by a fixing device 13, and is discharged onto a paper discharge tray 14.

The developing section 6 includes a first developing device 15 containing color toner and a second developing device 16 containing black toner. Each of the developing devices 15 and 16 is of a well-known magnetic brush type, and includes developing sleeves 15a and 16a having built-in magnetic rollers magnetized with N and S poles on their peripheries. The developer is made of a mixture of a magnetic carrier and an insulating toner, which are charged to opposite polarities by frictional charging, and the insulating toner is charged to an opposite polarity to that of the charger 10.

As shown in FIGS. 2 and 3, the cleaning device 8 includes a first blade 17 and a second blade 18 formed of an elastic material such as urethane rubber, which are attached to a blade holding member 19.
It is fixedly installed.

The blade holding member mechanism 9 is swingably supported by a shaft 20, is swingably biased counterclockwise by a spring 21, and clockwise by a solenoid 22 against the biasing force of the spring 21. It is configured to be driven in a swinging manner.

When the solenoid 22 is turned off and the blade holding member 19 is swung counterclockwise by the spring 21, the second blade 18 comes into pressure contact with the photoreceptor 5, as shown in FIG. 2, and the solenoid 22 is turned on. When the blade holding member 19 is swung clockwise, the first blade 1 is moved as shown in FIG.
7 is pressed against the photoreceptor 5.

The toner scraped off by the first blade 17 falls into the first toner collection groove 23 and is passed through the first toner conveying pipe 25 by the toner conveying coil 25a to the first developing device 15.
It is refluxed into the interior and collected.

Similarly, the toner scraped off by the second blade 18 falls into the second toner collection groove 24, and the toner conveying coil 26
At point a, the toner is refluxed into the second developing device 16 through the second toner transport pipe 26 and collected.

The solenoid 22, the first developer 15, and the second developer 16 are controlled by a solenoid drive circuit 27, a first developer drive circuit 28, and a second developer, respectively, which are controlled by the CPU 30 as shown in FIG. Drive is controlled by the device drive circuit 29, and C
The PU 30 is configured to control these drive circuits based on a predetermined program in response to input signals from a changeover switch 31 and a print switch 32 that issue a developer switching command.

Next, the operation will be explained with reference to timing diagrams shown in FIGS. 6 and 7. First, turn on the main switch of the copying machine to turn on the power. Next, as shown in FIG. 6, when the print switch 32 is turned on without operating the changeover switch 31, only the second developing device 16 containing black toner performs a developing operation. Also, solenoid 2
2 remains in the off state, and the second blade 18 is pressed against the photoreceptor 5 by the spring 21 as shown in FIG. The toner is collected, falls into the second collecting groove 24, passes through the second toner conveying pipe 26, returns to the second developing device 16, and is collected. Next, when making color copies, the seventh
As shown in the figure, by turning on the changeover switch 31, the solenoid 22 is turned on, and the second solenoid 22 is turned on as shown in FIG.
The first blade 18 is separated from the photoreceptor 5 and the first blade 17 is pressed against the photoreceptor 5. Next, when the print switch 32 is turned on, only the first developing device 15 containing color toner performs a developing operation. The color toner remaining on the photoreceptor 5 is scraped off by the first blade 17, falls into the first toner collection groove 23, and returns to the first developing device 15 through the first toner conveying pipe 25. and collected. If the print switch 32 is turned on for a predetermined period of time after the color copying operation is completed, the first developing device 15 is operated again and color copying is performed. However, if the print switch 32 is not turned on during this time, Even if the changeover switch 31 is not turned on, the auto clear automatically operates, the solenoid 22 is turned off, and the black toner copying mode using the second developing device 16 is restored.

Through the above-described series of operations, it is possible to recycle toner for each color in a copying apparatus capable of making two-color copies by one-touch operation of the changeover switch 31.

In the above embodiment, since the first and second blades 17 and 18 are fixed to the single blade holding member 19, it is possible to save space and reduce costs, but the present invention is limited to this. As shown in Figure 4,
The first and second blades 17.18 are respectively connected to shafts 20a,
Blade holding members 19a, 19 that can freely swing around 20b
b, and each blade holding member 19a, 1
9b to the respective springs 21a and 21tz! =7 The solenoids 22a and 22b are configured to be able to switch between a pressure contact position and a separation position with respect to the photoreceptor 5, and furthermore, the solenoids 22a and 22b are selectively turned on to switch between the first and second solenoids.
The blades 17 and 18 may alternatively be brought into pressure contact with the photoreceptor 5.

(Effects of the Invention) According to the image forming apparatus of the present invention, as is clear from the explanation below, when a desired developing device is selected, the cleaning blade and the reflux means corresponding to that developing device are activated. Therefore, toners from different developing devices are not mixed, and toner can be collected and reused even in an image forming apparatus equipped with a plurality of developing devices.

[Brief explanation of the drawing]

1 to 7 show an embodiment in which the present invention is applied to a copying device, FIG. 1 is a general schematic diagram of the copying device, and FIG. 2 shows the operating state of the second blade of the cleaning device. A front view, FIG. 3 is a front view showing the operating state of the first blade, FIG. 4 is a front view of the cleaning device of another embodiment,
FIG. 5 is a block diagram of the control device, and FIGS. 6 and 7 are operation timing diagrams when different developing devices are selected. Work 5 19a, 19b 22a, 22b 31- Cleaning device First developer Second developer First blade Second blade Blade holding member Blade holding member Solenoid Solenoid First conveyance pipe Second conveyance pipe switching switch.

Claims (1)

[Claims] (1) In an image forming apparatus in which developing devices of multiple colors are arranged side by side, a separate cleaning blade is provided corresponding to each developing device, and the toner scraped by each cleaning blade is transferred to the corresponding developing device. 1. An image forming apparatus comprising: a reflux means for refluxing the developer, and a means for switching the cleaning blade and the reflux means to an operating state corresponding to a selected developing device.