JPH02181758A - Method for recovering developer in developing device - Google Patents

Abstract

PURPOSE:To suppress the splash of toner and to recover a large quantity of toner in a short time by rotating a rotor for stirring developer, stopping a developing roller, recovering the developer, rotating the developing roller thereafter and recovering the remaining developer. CONSTITUTION:When a recovering port 23 is opened by turning a cover member 28 and the rotor 11 for stirring developer is rotated, the deteriorated developer in a developing tank 10Y is conveyed in an (a) direction and discharged from the recovering port 23 by an outside screw 12. Then, since the rotor 11 and the developing roller are separately driven and the developing roller is stopped while the developer is recovered, the toner is not splashed. When the recovery of the developer in the tank 10Y is finished, the developing roller is rotated in a rotating direction at developing time and the developer left between the rotor 11 and the developing roller is recovered. Thus, a large quantity of developer is recovered in a short time without splashing the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developer recovery method in a dry type developing device using powder developer.

[Conventional technology]

Dry-type developing devices, which are widely used in image forming devices such as copying machines, printers, and facsimiles, use a two-component developer consisting of toner and carrier as a powder developer, and a developing roller is rotated during development. The electrostatic latent image formed on the latent image carrier by the developer is visualized by the electrostatic latent image formed on the latent image carrier by the developer. When such a developer is used, the carrier deteriorates over time, so it is necessary to replace the entire developer with a new one as necessary. For this reason, conventionally, when the developer deteriorates, the developer in the developer tank is discharged to the outside by a developer conveyance/discharge means, and at that time, the developer is collected while the developing device is installed inside the machine body. configuration has been widely adopted.

[Problem to be solved by the invention]

By the way, in the past, the developer conveying and discharging means and the developing roller were configured to be driven simultaneously in synchronization, so if the developer conveying and discharging means was driven during developer collection, the developing roller would also operate in exactly the same way as during the developing operation. Rotate in a manner. Therefore, the developer in the developing tank is pumped up onto the developing roller and transported to the developing area where the latent image carrier and the developing roller face each other. At this time, since the portion of the developing roller facing the latent image carrier is exposed to the outside through the opening of the developing tank, toner in the developer conveyed to the developing area scatters to the outside. Even if the developer can be collected while the developing device is installed in the machine body, if the toner scatters as described above, there is a risk that the inside of the machine body will be contaminated with toner.

In addition, recent development devices have become smaller and the amount of developer in the developer tank tends to decrease, so even if a small amount of developer remains in the developer tank when collecting the developer, new developer is needed. When replenishing, the proportion of old developer left behind increases. Therefore, when recovering the developer, it is necessary to discharge as much developer as possible from the developing tank, but in conventional developer recovery methods, it has been difficult to recover all the developer in a short period of time. In particular, in a developing device in which a rotating body for stirring the developer is provided opposite to the developing roller, a small amount of developer remains between the rotating body and the developing roller, and it is difficult to completely discharge the developer in a short period of time. It was impossible to do so, and it took a lot of time to collect the developer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for collecting toner in a developing device that eliminates the above-mentioned conventional drawbacks, suppresses toner scattering as much as possible, and can collect many pairs of developer in a short period of time.

[Means to solve the problem]

In order to achieve the above object, the present invention includes: a developing tank containing a developer; a developing roller rotatable in both the rotational direction during development and the opposite direction; and a magnet fixedly disposed inside the roller. The developing tank includes a rotating body for agitating the developer, which is disposed at a position facing the developing roller and serving also as a means for transporting and discharging the developer during developer recovery, and the developing roller is arranged to agitate the developer. The magnet is not disposed within a certain range in the opposite direction from a position close to the rotating body for stirring the developer, and a magnetic shielding member is provided here, and the rotating body for stirring the developer is separated from the developing roller. In a developer recovery method in a developing device, in which the developer in the developer tank is transported and discharged to the outside and the developer is recovered with the driven developing device installed in the machine body, the developer stirring rotation When rotating the body to collect the developer, the developing roller is rotated in the opposite direction or kept stopped, and then the developer remaining between the developing roller and the rotating body for stirring the developer is removed. We propose a developer recovery method characterized by rotating a developing roller in the rotational direction during development to discharge the developer.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a developing device of a full-color copying machine will be described with reference to the drawings.

In FIG. 1, a yellow developing device 3Y, a magenta developing device 3M, and a cyan developing device 3C are provided below a drum-shaped photoconductor 1, which is an example of the configuration of a latent image carrier, and these developing devices are connected to a frame body. 21, and these can be pulled out to the front. The developing tanks 10Y, IOM, and IOC of each developing device contain a two-component developer (not shown) consisting of toner particles alone or toner with an additive added thereto and a carrier.
The colors of toner particles of Y, 3M, and 3C are yellow, respectively.
They are magenta and cyan.

Each developing device is provided with developing rollers 4Y, 4M, and 4C, which are arranged facing each other around the photoreceptor 1 with a predetermined gap therebetween.

Inside each of the developing rollers 4Y, 4M, and 4C, a magnet 5 and a magnetic shielding member 6 made of a magnetic material are arranged as shown in the figure.
etc. are provided, and these are held in a non-rotating state. On the other hand, each developing roller 4Y, 4M, 4C
are individually driven by drive motors (not shown), and are rotated in the direction of the solid line arrow during development. From now on, when rotating in this direction,
r normal rotation.'' As will be described later, the developing roller can also rotate in the direction shown by the broken line arrow, and the rotation direction during development (
It is possible to rotate in both directions (forward rotation) and the opposite direction (reverse rotation).

The developer contained in each developing tank IOY, IOM, and IOC is agitated by a developer agitating rotating body 11. Each stirring rotary body 11 is connected to each developing tank IOY, IOM, I.
It is disposed inside the OC at a position facing each of the developing rollers 4Y, 4M, and 4C, and includes an external screw 12, an internal screw 13, and a stirring paddle 14, and rotates clockwise to stir the developer. , each developing roller 4Y, 4
Supplies developer to M and 4C. Rotating body 11 for stirring developer
is driven separately from each developing roller (the driving sources may be separate or the same driving source). Further, as will be described later, the developer stirring rotary body 11 also serves as a developer transporting and discharging means when recovering the developer.

The developing rollers 4Y, 4M, and 4C are rotating bodies 11 for stirring the developer.
A certain range in the opposite direction (in the direction of the dashed arrow) from a position adjacent to (however, the range in front of the development area described later)
The magnet 5 is not disposed at , and the above-mentioned magnetic shielding member 6 is located here.

Here, to explain the developing operation using the yellow developing device 3Y as an example, the developer supplied to the developing roller 4Y is carried on the developing roller 4Y by the rotation (normal rotation) of the roller and the magnetic force of the internal magnet 5. Doctor Blade 3
1 to a predetermined thickness, and is transported in the same direction as the normal rotation direction of the developing roller 4Y (direction of arrow A). When this developer rotates clockwise, the photoreceptor 1 and the developing roller 4
When reaching the development area facing Y, it contacts the photoconductor 1, and the yellow toner in the developer electrostatically transfers to the electrostatic latent image on the photoconductor, making the latent image yellow. Visualized.

When the developer subjected to development reaches the position of the magnetic blocking member 6 in the developing roller 4Y, the magnetic force on the developing roller 4Y is substantially eliminated, so the developer leaves the developing roller 4Y as shown by arrow B, and the developer It falls onto the rotating body 11 for stirring.

The visible image formed on the photoreceptor 1 is transferred to a transfer paper on a transfer drum (not shown) that is in contact with the photoreceptor 1.

Similarly, a visible image of magenta toner is formed on the photoreceptor 1 by the magenta developing device 3M.

Further, a cyan developing device 3C is configured to obtain visible images using cyan toner, and these visible images are sequentially superimposed on the transfer paper on the transfer drum. After all such transfer is completed, the transfer paper is removed from the transfer drum, fixed, and then discharged outside the machine as color copy paper or color recording paper.

Here, when the yellow developing device 3Y is performing development, the developing rollers 4M and 4C of the other developing devices are in a state of cutting so that the developing operation is not performed. Furthermore, when the magenta developing device 113M is performing development, the developing rollers 4Y and 4 of the other developing devices
C is in the state of cutting ears. Further, when the cyan developing device 3C is performing development, the developing rollers 4Y and 4M of the other developing devices are in a state of cutting.

The purpose of this is that if the developing rollers other than the developing roller during the developing operation are not trimmed, the visible image of the respective colors formed on the photoreceptor 1 may be disturbed or color mixing may occur. It is from.

Here, for example, assuming that ear cutting is performed at the developing roller 4Y, this is performed as follows.

As mentioned earlier, on the developing roller 4Y.

When this rotates normally in the direction of the solid line arrow, the developer is magnetically drawn up and carried, but when cutting the ears, it is rotated in the direction of the broken line arrow. In other words, it is reversed.

During such rotation, there is a magnetic shielding member 6 in the region where the developer is to be pumped up, and no magnet is provided in this opposing portion, so that a
The t-force disappears or almost disappears, and the developer is no longer pumped up, leading to a state of cutting where there is substantially no developer on the developing roller. The flow of the developer at this time is indicated by an arrow C. Normally, the ear cutting operation can be completed by reversing the developing roller 4Y once or several times.

Such ear cutting is performed in exactly the same manner for the other developing rollers 4M and 4C.

Each of the developing rollers 4Y, 4M, and 4C is stopped at times other than the developing operation and the ear cutting operation.

On the other hand, the developer agitating rotor 11 continues to rotate and agitates the developer even when the developing roller is stopped.

Next, an explanation will be given of the developer stirring rotating body 11, a more specific configuration related thereto, and an example of its operation during developer recovery, with the yellow developing device 3Y as the focus.

FIG. 2 is a perspective view showing the structure of the rotating body 11 for stirring the developer, and this rotating body 11 includes the stirring paddle 14 as described above.
, an external screw 12 wound around this, and an internal screw 13 provided on a shaft 30 inside the stirring paddle 14.

The stirring paddle 14 is provided with a developer inlet 15, and a developer outlet 16 is provided on the back side thereof.

As shown in FIG.
, 17, 18, respectively, and the stirring paddle 14, which has an external screw 12, is rotatably driven by a drive gear (not shown) provided on the rear end side (the gear 19 is connected to the stirring paddle and is rotated by the paddle).

In FIG. 2, when the stirring paddle 14 and the shaft 3o rotate, the developer is carried in the direction of arrow a by the external screw 12 of the stirring paddle 14. During this time, the developer enters the stirring paddle 14 through the developer inlet 15, and after that,
It is carried by the internal screw 13 in the direction of the arrow. Then, the developer exiting the developer discharge port 16 is transported again in the direction of arrow a. In this manner, the developer circulates in and out of the stirring paddle 14 while being stirred.

While the developer is conveyed in the direction of arrow a from the developer discharge port 16 side, the stirring paddle 14 moves the developing roller 4Y (first
(Figure) is supplied with developer.

In FIG. 1, the front side of the rotating body 11 for agitating the developer is the developing tank IO, as shown in FIG.
It protrudes from Y. That is, in FIG. 3, it protrudes to the left from the developing tank IOY. This protrusion has
Developing tank 10Y.

The end portions of 10M and IOc are fixed, and are surrounded by a developer inflow/outflow tubular portion 21Y integrally formed in a boss shape with a fixed support plate 33 constituting a side plate. As shown in FIG. 4, the fixed support plate 33 held in an immovable state includes a tubular part 21Y, a tubular part 21M for the magenta developing device, and a tubular part 21C for the cyan developing device, as shown in FIG.
are provided for each. A common support member (side plate), not shown, is also fixed to the other end of each developing tank.

In FIG. 3, the developer inflow/outflow tubular portion 21Y is provided with a developer inlet 22 on the upper side and a developer recovery port 23 on the lower side. This recovery port 23 is normally closed by a lid member 28.

A hopper-shaped toner container 25Y containing yellow toner for replenishment is integrally provided on the movable plate 24. In addition to the toner container 25Y, there are also a magenta toner container 25M and a cyan toner container 2 as shown in FIG.
5C is integrally provided.

In FIG. 3, there is an agitator 2 in the toner container 25Y.
6 is provided, and by swinging this, crosslinking of the toner in the toner container is prevented.

In FIG. 1, when the toner concentration sensor 20 detects that the toner concentration of the developer in the developer tank IOY has become lower than the reference concentration, in FIGS. The toner supply roller 7Y is configured to rotate.

Then, the yellow toner in the toner container 25Y is caused to fall by the roller 7Y, and this fallen developer flows into the tubular portion 21Y through the developer inlet 22. Next, the developer enters the stirring paddle 14 through the inlet 15 of the stirring paddle 14, and is conveyed in the direction of the arrow while being stirred with the developer by the internal screw 13. In this way, toner is replenished. In this case, the inflow port 22 will function as a toner supply port. Such toner replenishment is performed in exactly the same way for the magenta developing device and the cyan developing device.

If a developing device configured as described above is used for a long period of time, the carrier in the developer will deteriorate, and if left untreated, the photoreceptor 1 will deteriorate.
The quality of the visible image formed thereon is degraded. Therefore, in such a case, it is necessary to replace the developer in the developing tank with a new one.

This developer recovery operation is performed as follows.

That is, with the developing device attached to the machine body ('f!1 copying machine body), the lid member 28 shown in FIG. 3 is rotated in the direction of the arrow around the hinge pin 29 to open the collection port 23. . In this state, by rotating the developer stirring rotor 11, the deteriorated developer in the developer tank is conveyed in the direction of arrow a by the external screw 12 and discharged from the recovery port 23. That is, the developer is collected. In this way, the rotating body 11 for stirring the developer
also serves as a developer conveying and discharging means during developer recovery.

As mentioned above, when collecting the developer, in the conventional developing device, the developer conveying and discharging means and the developing roller rotated simultaneously in synchronization, so the developer was conveyed to the part of the developing roller exposed through the opening at the top of the developer tank. There was a risk of toner scattering.

Therefore, in the configuration according to the present invention, the developing roller and the developer stirring rotor 11 are driven separately as described above, and when collecting the developer, (1) the developing roller 4Y is reversed as described above; The developer on the developing roller is removed and the ears are cut, or (2) the developing roller 4Y is kept stopped.

In this state, the developer stirring rotor 11 is rotated as described above to transport and discharge the developer.

In this way, there is no developer on the developing roller 4Y, or even if there is, it is stopped, so the above-mentioned toner scattering can be prevented.

When cutting the ears as in (2), the developing roller 4Y may be stopped after cutting the ears, or may continue to be rotated in reverse. In either case, since there is no developer on the developing roller 4Y, toner will not be scattered. Further, the timing for starting the reverse rotation of the developing roller 4Y may be after the rotating body 11 for agitating the developer is rotated in order to transport and discharge the developer, or may be before the rotation starts.

Even when the developing roller 4Y is initially stopped as shown in (2), the developing device 3Y in FIG. 1 is already in the cutting state, so there is virtually no developer on the developing roller 4Y. , there is no problem even if the developer is carried on the developing roller 4Y.

This is because, as described above, if the developing roller does not rotate, the developer remains stationary and the toner does not scatter.

As described above, it is possible to prevent the inconvenience of staining the inside of the copying machine body with toner.

By the way, when the developer collection operation is completed with the developing roller 4Y reversed or stopped, some developer held by magnetic force remains in the area between the developing roller 4Y and the rotating body 11 for stirring the developer. If it takes a long time, it is possible to recover the residual developer by the above-mentioned operation alone, but this is not preferable because the working efficiency decreases.

Therefore, in the method according to the present invention, the above-described operation is further performed to recover almost all the developer in the developing tank 10Y, and then the developing roller 4Y is moved in the rotational direction during development by, for example, 2 to 3 times.
It rotates in the normal direction about 100 times.

In this way, the developer remaining between the rotating body 11 and the developing roller 4Y is carried by the developing roller 4Y and is then separated from the developing roller 4Y by the action of the magnetic shielding member 6, so that it is not a hindrance. The developing tank l is moved by the rotating body 11 for stirring the developer.

It can be discharged outside Y.

The developing roller 4Y may be rotated normally when some developer other than the residual developer remains in the developing tank 10Y. In this case, although a somewhat larger amount of developer is transported by the developing roller 4Y, since the amount of remaining developer is originally small, toner scattering hardly occurs.

In this way, the residual developer between the developing roller 4Y and the rotating body 11 can also be quickly recovered.

Furthermore, in addition to rotating the developing roller 4Y in the normal direction as described above, by continuously rotating the developing roller 4Y in the reverse direction and repeating the forward and reverse rotation several times, it is possible to apply external forces in different forms to the residual developer, thereby increasing the recovery efficiency. can be increased.

Developer can be collected from the other developing devices 3M and 3C in exactly the same manner as described above.

Since the developer can be collected without considering the scattering of the developer, it is also possible to increase the number of revolutions of the rotating body 11 for stirring the developer and shorten the collection time.

When replenishing the developer tank with new developer, close the lid member 28, remove the toner containers 25Y, 25M, and 25G shown in FIGS. 3 and 4, open the developer inlet 22, and then New developer is replenished from the developer tank, and the developer is fed into the development tank while rotating the developer stirring rotor 11. At this time, the developing roller is stopped or reversed to prevent the developer from being conveyed on the developing roller. This is to prevent toner from scattering.

In addition, each toner container 25Y, 25M, 25 shown in FIG.
A movable plate 24 integrally provided with C is rotatably supported with respect to hinge pins 27 provided on bent portions 21a and 21b of a fixed support plate 33, and each toner container is normally provided with a developer at the bottom thereof. The outflow portion is located at a position corresponding to the developer inlet 22, and when filling with new developer, the movable plate 24 is rotated toward the front in FIG. 4 around the hinge pin 27, and the developer inlet 22 is opened and new developer is allowed to flow in from this inlet 22, replenishing the developer can be easily performed.

It should be noted that each of the above-mentioned operations during developer collection can be configured to be performed automatically by the control device of the copying machine, or a key switch can be provided to operate the developing roller and the rotating body for stirring the developer. This can also be done by pressing the button each time.

It goes without saying that the present invention can be applied to image forming apparatuses other than color copying machines, or image forming apparatuses having a number of developing devices other than three.

〔Effect of the invention〕

According to the present invention, the developer can be recovered without scattering the toner, and moreover, it is possible to recover a large amount of the developer in the developer tank in a short time.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a developing device in an embodiment of the present invention;
3 is a sectional view of the toner replenishing section in the above embodiment, and FIG. 4 is a view of the toner container section. 4Y, 4M, 4C...Developing roller 5...Magnet 6...Magnetic shielding member 10
Y, 10M, IOC... Developing tank 11... Rotating body for developer stirring Agent Patent attorney Norio Hoshino

Claims (1)

[Scope of Claims] A developing tank containing a developer, a developing roller rotatable in both the rotation direction during development and the opposite direction, a magnet fixedly arranged inside the roller, and an inside of the developing tank. The developing roller has a rotating body for agitating the developer, which is disposed at a position facing the developing roller and also serves as a developer transporting and discharging means when recovering the developer, and the developing roller is connected to the rotating body for agitating the developer. A developing device in which the magnet is not disposed within a certain range in the opposite direction from an adjacent position, a magnetic shielding member is provided here, and the rotating body for stirring the developer is driven separately from the developing roller. With the device installed inside the machine,
In the developer recovery method in the developing device, in which the developer in the developer tank is conveyed and discharged to the outside and the developer is recovered, when the developer is recovered by rotating the developer stirring rotary body, the developing roller is Rotate the developing roller in the opposite direction or keep it stopped, and then rotate the developing roller in the direction of rotation during development in order to discharge the developer remaining between the developing roller and the rotating body for stirring developer. A developer recovery method characterized by: