JPH07311529A - Image forming device - Google Patents

Abstract

PURPOSE:To smoothly carriers included in the recovered toner to a developing device, in an image forming device provided with a recovered toner carrying path between the developing device and a cleaning device. CONSTITUTION:A recovered toner discharge member 15 carrying the toner recovered by a cleaning blade 13 is provided in parallel with a photoreceptor 1 in the cleaning device 10. The recovered toner is discharged into a toner carrying tube 18 provided between the cleaning device 10 and the developing device 4 from the cleaning device 10 by the toner discharge member 15 and a recovered toner carrying member 19 carrying the recovered toner into the developing device 4 is provided so as to insert into the toner carrying tube 18 and rotated even after the actuation of the recovered toner discharge member 15 is stopped.

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 of a type in which toner collected from an image carrier is reused in a developing device by a cleaning device.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer or a facsimile, an electrostatic latent image is formed on an image bearing member such as a drum-shaped or belt-shaped photosensitive member, and this is visualized as a toner image by a developing device. After the image is formed and transferred to a recording medium, the toner that did not contribute to the transfer is removed from the image carrier by a cleaning device and collected, and the collected toner is returned to the developing device for reuse. Such a method is conventionally known.

In this type of image forming apparatus, a collected toner discharging member including a screw member and a coil spring provided in the main body of the cleaning device conveys the collected toner in the axial direction of the image carrier and collects the collected toner. The collected toner conveying member in the toner conveying pipe provided between the cleaning device and the developing device is used to feed the toner toward the developing device. As such a collected toner conveying member, for example, a screw member or a coil spring is used, and the toner conveying member is rotationally driven to convey the toner toward the developing device.

In this type of image forming apparatus, the recovery toner discharge port from the cleaning device is located at a position lower than the recovery toner receiving port on the developing device side in view of restrictions on layout of various image forming process devices. It is often installed. In the case of such a configuration, since the recovery toner transport path is inclined so as to rise from the cleaning device side toward the developing device side, the recovery toner in the transport path is transported against gravity. .

By the way, in this type of image forming apparatus, a powdery two-component developer having a toner and a carrier, or a developing device for visualizing an electrostatic latent image formed on an image carrier is used. Although a powdery one-component developer containing no carrier is used, when the former developing device using a two-component developer is adopted, the toner on the image carrier is developed during the development. Not only that, but a very small amount of carrier also adheres. Therefore, when the toner remaining on the image carrier is recovered by the cleaning device after the toner image on the image carrier is transferred onto the recording medium, the recovered toner also contains a small amount of carrier. However, since this carrier has much better fluidity than toner,
When the collected toner is conveyed to the developing device by the collected toner conveying member, it is difficult to efficiently convey the carrier mixed in the collected toner. In particular, as described above, when the toner conveying pipe forming the conveying path for the collected toner is inclined so as to rise toward the developing device, the collected toner is conveyed against gravity, so For the carrier with good fluidity, the transportability of the collected toner transport member becomes very poor, and the carrier unavoidably stays on the lower side of the toner transport tube (cleaning device side).
It becomes easy to deposit on this part.

If the carrier in the collected toner accumulates on such a portion, the rotation torque of the collected toner conveying member in the toner conveying pipe becomes unnecessarily large, and the rotation of the member is hindered. In such a case, the ability of the collected toner to be conveyed may be lowered, which may hinder the conveyance of the collected toner to the developing device. Then, in some cases, the collected toner conveying member may be in a locked state, and the collected toner may not be conveyed.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to develop a collected toner containing a carrier having good fluidity and difficult to carry in an image forming apparatus in which a carrying path for the collected toner is provided between a developing device and a cleaning device. An object of the present invention is to provide an image forming apparatus that can be smoothly conveyed to the apparatus.

[0008]

In order to achieve the above object, the present invention provides an electrostatic latent image by an image carrier on which an electrostatic latent image is formed and a two-component developer having toner and carrier. A developing device that visualizes as a toner image, a cleaning device that transfers the visualized image on the image carrier to a recording medium, and then removes and collects toner remaining on the image carrier.
By being driven to rotate, the collected toner in the cleaning device is conveyed from one end side in the axial direction of the image carrier toward the other end side, and the collected toner is discharged to the outside of the cleaning device. A discharging device, a toner carrying pipe connected between the other end side of the cleaning device and the developing device, and a toner carrying pipe inserted into the toner carrying pipe and rotationally driven to collect the toner by the collected toner discharging member. An image forming device including a collected toner conveying member that conveys the collected toner discharged from the toner conveying pipe to the developing device in the toner conveying pipe and continues rotating for a certain period of time even after the collected toner discharging member stops. It proposes a device.

At this time, it is effective to attach a container for accommodating the carrier contained in the recovered toner to the toner conveying pipe portion near the connecting portion between the toner conveying pipe and the cleaning device.

Further, it is particularly effective to detachably connect the container to the toner carrying tube.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing only a main part of an image forming apparatus according to an embodiment of the present invention, and this image forming apparatus has respective elements described below. In the figure, reference numeral 1
Shows a drum-shaped photoconductor that is an example of the configuration of the image carrier,
The photoconductor 1 is adapted to be rotationally driven around the central axis in the direction of the arrow shown in the figure. During this rotation, the surface of the photoconductor 1 is a charging charger 2 which is an example of a charging device.
Is uniformly charged by the action of. Then, an exposure device (not shown) performs image exposure or optical writing in the exposure section 3 to form a predetermined electrostatic latent image on the photoconductor 1. The charging charger 2 and the exposure device constitute an example of a latent image forming unit that forms an electrostatic latent image on the photoconductor 1. A belt-shaped photosensitive member may be used, or an electrostatic latent image may be formed on the surface of the image bearing member made of a dielectric material by a latent image forming means including a charging device and a multi-stylus.

A developing device 4 is disposed opposite to the photosensitive member 1,
A two-component developer (not shown) having toner and carrier is accommodated in the developing casing 5 which is the main body. Such a developer is carried on the developing roller 6 facing the photoconductor 1, and the carried developer is conveyed on the roller along with the rotation in the direction of the arrow, and in the developing area facing the photoconductor 1. The electrostatic latent image formed on the photoconductor 1 is visualized as a toner image by the toner in the developer. In this way, the developing device 5 visualizes the electrostatic latent image as a toner image with the two-component developer having toner and carrier.

On the other hand, the recording medium 8 made of, for example, transfer paper is fed toward the photoconductor 1 by the pair of registration rollers 7, and the visible image formed on the photoconductor 1 is
By the operation of the transfer charger 9 which is an example of the transfer device,
It is transferred onto the recording medium 8.

A cleaning device 10 is arranged opposite to the developing device 4 on the photosensitive member 1, and the cleaning device 10 has a cleaning blade 13 as an example of a cleaning member. After the transfer, the toner remaining on the surface of the photoconductor 1 is scraped off and removed. Then, the removed toner is collected in the casing 12 forming the main body of the cleaning device 10. In this way, the cleaning device 1
0 indicates that after the visible image on the photoconductor 1 is transferred to the recording medium 8,
It is used to remove and collect the toner remaining on the photoreceptor 1.

After the surface of the photoconductor 1 is thus cleaned, the surface of the photoconductor 1 is destaticized by the action of the destaticizer 14. In this way, one image forming cycle is completed, but when the next image forming cycle is subsequently executed, the above-described operation is continuously executed that number of times.

Here, in the main body of the cleaning device 10,
That is, in the lower part of the casing 12, a collected toner discharging member 15 made of, for example, a coil spring or a screw member is arranged along the axial direction of the photoconductor 1.
The collected toner discharge member 15 is connected to a gear 17 provided outside the casing 12, and a drive gear 16 meshes with the gear 17. When the drive gear 16 is rotated by a motor (not shown), the collected toner discharging member 15 rotates around its own central axis via the gear 17, and accordingly, the toner collected in the casing 12 is transferred to the photosensitive member 1. A collected toner discharge port formed on the side wall of the casing 12 that is conveyed from one end side (the end side of the inner part in the drawing) in the axial direction toward the other end side (the end side of the front side). Through the casing 12 to the outside. In this way, the toner discharge member 15 is driven to rotate, so that the toner collected in the cleaning device 10 can be collected.
The toner is conveyed from one end side to the other end side in the axial direction of and the collected toner is discharged to the outside of the main body of the cleaning device 10. At that time, the above-mentioned gear 17,
The drive gear 16 and the motor constitute an example of a drive unit that rotationally drives the collected toner discharging member 15.

The main body of the cleaning device 10, that is, the other end side of the casing 12 (front end in the figure).
And a developing device 4 are connected to a toner carrying pipe 18 so as to straddle the front end of the photoconductor 1, and inside this, a collected toner composed of a coil spring or a screw member as shown in the drawing. The transport member 19 is inserted. The shaft 20 is fixed to one end of the collected toner conveying member 19,
A bevel gear 22 is fixed to the shaft 20. Bevel gear 2
2, a driving bevel gear 21 meshes with the driving bevel gear 21, and when the driving bevel gear 21 is rotationally driven by a motor (not shown),
The collected toner conveying member 19 is rotationally driven around its own central axis. The bevel gear 22, the driving bevel gear 21, and the motor constitute an example of a drive unit that rotationally drives the collected toner conveying member 19, and in the present example, the collected toner conveying member 19.
However, it is adapted to be driven by a drive system different from the collected toner discharge member 15 on the cleaning device side.

When the collected toner conveying member 19 is rotationally driven in this manner, the collected toner discharged from the casing 12 of the cleaning device 10 into the toner conveying pipe 18 by the collected toner discharging member 15 is collected in the toner conveying pipe. Is conveyed toward the developing device 4, and is put into the developing casing 5 of the developing device 4 from the collected toner receiving port 11 of the developing device 4. The collected toner is collected by the developing device 4
Will be reused in.

As described above, a two-component developer is used in the developing device 4 of the image forming apparatus shown in the figure, and an electrostatic latent image is converted into a toner image by such a developer. Then, even a very small amount of the carrier in the developer adheres to the surface of the photoconductor 1, and thus the cleaning device 1
A small amount of carrier is also mixed in the toner collected by 0. Since such a carrier has very good fluidity, it has poor transportability, and the toner collected by the cleaning device 10 may be transported by the recovered toner transport member 19 in the toner transport tube 18. Similarly, the carrier property of the recovered toner is poor.

In particular, as shown in the drawing, the toner carrying pipe 18
However, when it takes a tilted position that increases toward the developing device 4,
Since the transportation is performed against gravity, the transportation of the carrier in the collected toner becomes worse. In this case, the carrier is likely to stay and accumulate in the upstream side portion (the lower end area of the toner carrying tube) in the toner carrying tube 18, and if it is left unattended, the rotation torque of the collected toner carrying member 19 is increased. Becomes larger than necessary, and the conveying ability of the collected toner is reduced.

Therefore, in the illustrated image forming apparatus, the collected toner conveying member 19 is driven by a controller (not shown) so that it continues to rotate for a certain period of time even after the collected toner discharging member 15 is stopped. It is configured to be controlled. As described above, the collected toner conveying member 19 is driven by the driving means separately from the collected toner discharging member 15, and is rotated for a certain time even after the collected toner discharging member 15 is stopped. It is supposed to continue. The collected toner discharging member 15 is 1
When one or a plurality of continuous image forming cycles are started, for example, rotation of the photoconductor 1 is started at the same time as the start of rotation, and with the end of one or more series of image forming cycles, For example, the rotation of the photosensitive member 1 is stopped at the same time as the stop of the photosensitive member 1, but even after the rotation of the collected toner discharging member 15 is stopped in this way, the collected toner conveying member 1 is held for a certain time.
9 is rotated. With this configuration, the collected toner discharged by the collected toner discharging member 15 to the upstream side portion, which is the lower end area of the toner conveying tube 18, is started together with the carrier contained therein in the next image forming cycle. Since all or most of them can be conveyed to the developing device 4 by the time the toner is conveyed, it is possible to prevent the carriers having poor conveying properties from accumulating in the toner conveying pipe 18 or to reduce the accumulation amount. Therefore, the collected toner can be efficiently conveyed to the developing device 4 during the next image forming cycle, and the rotation torque of the collected toner conveying member 19 can be prevented from becoming excessive. Here, the fixed time period during which the collected toner conveying member 19 is rotated even after the collected toner discharging member 15 is stopped means the toner conveying pipe 18 after the end of the image forming cycle.
In order to prevent carrier retention in the upstream part of
Alternatively, the time is such that all or a large amount of the carrier having good fluidity can be returned to the developing device 4 together with the collected toner so that the amount thereof becomes small.

A transport path for the collected toner is formed in the toner transport tube 18. By adopting the above-described configuration in the image forming apparatus having such a transport path, the fluidity is improved. Since the carrier with poor transportability can be smoothly returned to the developing device, a large amount of the carrier in the recovered toner does not accumulate in the upstream side portion of the transport path. It is possible to prevent the rotation torque of the member 19 from increasing and prevent the collected toner carrying ability from decreasing.

Even if the above-mentioned structure is adopted, when a carrier having a very good fluidity, which tends to be deposited, is used, the toner in the vicinity of the connecting portion between the toner carrying pipe 18 and the cleaning device 10 is used. A container 23 is provided integrally with the conveying pipe portion, for example, the uppermost stream side portion of the toner conveying pipe 18 (the lowermost lower end portion thereof) as shown in FIG. By accommodating such a carrier, it is possible to effectively prevent the carrier from accumulating in the toner transport pipe 18. As a result, it is possible to prevent the rotation torque of the collected toner conveying member 19 from increasing, and it is possible to prevent the conveying ability of the collected toner from decreasing.

Since the recovered toner itself has poor fluidity and good transportability as compared with the carrier, the toner transfer tube 18 is unlikely to move in the upstream direction, and the recovered toner transfer member 19 positively moves. Since the toner is conveyed in a desired manner, a large amount of toner does not enter the container 23. In this way, it is possible to prevent a decrease in the transport capability of the collected toner over time.

The container 23 for accommodating the carrier may be detachably connected to the toner carrying tube 18 as shown in FIG. By doing this, with a certain amount of carriers accumulated in the container 23, a
The carrier in the container 23 can be discarded or returned to the developing device 4. After that, the container 23 is mounted on the container mounting portion 18A of the toner carrying tube 18. By doing so, the container 23 can be used many times, and with respect to the carrier accommodating container 23, the capacity is not increased so much and the carrier is accumulated to some extent.
If the carrier is discarded or returned to the developing device 4 and this operation is performed several times, it is possible to avoid the problem that the image forming apparatus main body becomes large.

Here, FIG. 3 shows the photosensitive member 1, the developing device 4,
FIG. 3 is a configuration perspective view showing an example of an image forming process cartridge in which a cleaning device 10, a toner carrying tube 18, a collected toner carrying member 19, a carrier accommodating container 23 and the like are integrated.

For this type of image forming process cartridge, the life of the cartridge is determined in consideration of the life of the carrier of the developer and the life of the photoconductor. For example, the life of the carrier and the life of the photoreceptor 1 can be replaced with the number of durable copies, and the cartridge life can be determined from this number of copies. Since the total amount of carriers in the collected toner corresponding to the number of durable copies can be calculated in advance, the capacity of the carrier storage container 23 is
By setting the capacity so that a slightly larger amount of carriers can be accommodated, it is possible to save the trouble of discarding the accommodated carriers on the way.

That is, when the image forming process cartridge is replaced, the accommodating carrier as well as the cartridge can be discarded, and the maintenance-free function, which is an advantage of the process cartridge, can be exerted. In this case, of course, the original function of not lowering the collected toner transporting ability can be achieved.

It should be noted that the combination of the process devices constituting the image forming process cartridge is not necessarily limited to the one shown in FIG. 3, and various combinations are possible. For example, at least the photoconductor 1, which is an image carrier, the cleaning device 10, and the toner carrying tube 18 are integrated into an image forming process cartridge, and the carrier accommodation amount of the container 23 is determined by the life of the process cartridge, that is, its durability. It can be set to be equal to or more than the amount of carriers discharged into the container 23 during the number of copies.

[0031]

According to the image forming apparatus of the first aspect, the carrier contained in the collected toner, which has good fluidity and is difficult to be carried, can be smoothly returned to the developing device and carried, and the collected toner can be carried. Since it is possible to prevent the accumulation of carriers on the upstream side portion of the conveyance path, it is possible to prevent the conveyance ability of the collected toner from decreasing.

According to the image forming apparatus of the second aspect,
Even if a carrier that is extremely easy to flow is mixed in the collected toner, since such a carrier can be stored in the container, it is possible to prevent the accumulation of the carrier at the upstream side portion of the collected toner conveying path and to improve the collected toner conveying ability. It can be effectively prevented from decreasing.

According to the image forming apparatus of the third aspect,
The carrier collected in the container can be easily discarded or returned to the developing device, the carrier accommodating container can be used many times, and the container can have a small capacity. Therefore, it is possible to prevent the problem that the main body of the image forming apparatus becomes large.

[Brief description of drawings]

FIG. 1 is a sectional view showing only a main part of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an embodiment in which a container accommodating a carrier is detachably configured.

FIG. 3 is a configuration perspective view of an image forming process cartridge in which a photoconductor, a developing device, a cleaning device, a toner transport tube, and the like are integrated.

[Explanation of symbols]

 4 Developing Device 8 Recording Medium 10 Cleaning Device 15 Collected Toner Discharging Member 18 Toner Conveying Pipe 19 Collecting Toner Conveying Member

Claims (3)

[Claims] 1. An image carrier on which an electrostatic latent image is formed, a developing device which visualizes the electrostatic latent image as a toner image by a two-component developer having a toner and a carrier, and an image carrier. Cleaning device that removes and collects the toner remaining on the image carrier after transferring the visible image of the toner to the recording medium, and the toner collected in the cleaning device is rotated in the axial direction of the image carrier when the cleaning device rotates. Between the one end side of the cleaning device and the other end side of the cleaning device and the developing device that conveys the collected toner to the outside of the cleaning device. And the collected toner discharged from the cleaning device by the collected toner discharging member into the toner carrying tube by being inserted into the toner carrying tube and rotationally driven. An image forming apparatus, comprising: a collected toner conveying member that conveys the collected toner toward a developing device in a conveying pipe and continues rotating for a certain period of time after the collected toner discharging member stops. 2. The image forming apparatus according to claim 1, wherein a container for accommodating the carrier contained in the recovered toner is attached to the toner conveying pipe portion near the connection portion between the toner conveying pipe and the cleaning device. 3. The image forming apparatus according to claim 2, wherein the container is detachably connected to a toner transport tube.