JPH06308829A - Developing device - Google Patents

Abstract

PURPOSE:To provide a developing device that replaces part of carrier in a developing unit with fresh one each time a toner supply cartridge is replaced due to toner end, and recycles most of waste toner. CONSTITUTION:The dry type developing device of two-component system discharges premix agent 11, in which carrier is mixed, into the toner supply cartridge 10 and supplies the discharged premix agent 11 to the developing unit 6 according to a decrease in the concentration of toner in the developer 9. The developing device is provided with a developer circulation device 27 for circulating the carrier, which has overflowed by the supply of the premix agent 11, to the toner supply cartridge 10 again from the developing unit 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry two-component developing device in an electrophotographic copying machine.

[0002]

2. Description of the Related Art In a conventional electrophotographic copying machine, a toner replenishing cartridge is filled with a premix agent mixed with a carrier, and the filled premix agent is developed in accordance with a decrease in toner concentration in the developer. Some are equipped with a dry two-component developing device that replenishes the container side.

In this case, dust and coarse toner are directly developed, causing an abnormal image. Therefore, in order to prevent such a phenomenon, the developing device is provided with a device for collecting dust, for example. As for such a recovery device, there are various conventional examples as described below. First, as a first conventional example, there is one disclosed in Japanese Patent Application Laid-Open No. 60-10274 under the name of "developing device". This allows the housing of the developing device and the collected developer mixing chamber to pass through by a mesh (communication wall) so that dust, paper fibers, and development clumps in the developer do not enter the housing. Next, as a second conventional example, there is one disclosed in JP-A-61-2172 and JP-A-61-2173 under the name "toner storage device of electrostatic transfer device".
In this case, in the former example, a toner transport unit for discharging toner is formed in the toner storage unit formed on the photoconductor drum, thereby reducing the size of the developing device. Also,
In the latter example, the toner storage unit is provided in the photosensitive drum to supply the toner to the developing roller, and the collected toner is distinguished from the unused toner and is retained on the photosensitive drum to reduce the size of the toner storage device. There is. Next, as a third conventional example, there is an application filed by the present applicant under the name "toner cartridge" in Japanese Patent Application Laid-Open No. 63-298370. This is a mechanism for sending the toner collected by the toner collecting section attached to the cleaning device to the toner storing section, so that the used toner and the new toner are prevented from being mixed with each other. In addition, as another conventional example, Japanese Patent Laid-Open No. 60-146
No. 265, "Toner Replenishing Device in Dry Copier"
There is a patent application filed by the present applicant under the name of "Developer discharging device and method thereof" in Japanese Patent Application Laid-Open No. 61-9666, but the description thereof is omitted here. .

[0004]

As described in the above-mentioned conventional examples, in the mechanism provided with the toner collecting device,
If the toner remaining after the transfer by the photosensitive drum is stored in the discharged toner tank in the machine, it is necessary to collect the toner periodically, which is troublesome. In addition, in order to suppress the frequency of the periodical collection intervals, the tank must be made large and the device itself must be large, and the operation process is complicated due to the addition of a troublesome process for the toner replenishing operation. Will increase. Further, since the toner is scattered during the collection and dust or the like accumulated in the main body of the developing device must be cleaned, the work efficiency is poor.

Further, in order to eliminate the periodical toner replacement work and reduce the operation steps relating to toner replacement,
Although it is desired to develop a recycling system that reuses toner that has been used once, there are few concrete examples of conventional toner replenishing devices that utilize toner recycling in consideration of the above-mentioned problems.

[0006]

According to a first aspect of the present invention, a toner replenishing cartridge is filled with a premix agent mixed with a carrier, and the filled premix agent reduces the toner concentration in the developer. In a dry two-component type developing device which replenishes the developer to the developing device side, a developer recirculation device for recirculating the carrier overflowed by replenishment of the premix agent from the developing device to the toner replenishing cartridge side again. Was set up.

According to the second aspect of the present invention, the toner replenishing cartridge is filled with the premix agent mixed with the carrier, and the filled premix agent is sent to the developing device side in accordance with the decrease of the toner concentration in the developer. In a dry two-component developing device for replenishing, a developer recirculation device for recirculating the carrier overflowed by replenishment of the premix agent from the developing device to the toner replenishment cartridge side is provided. A carrier recovery container was provided for trapping the carrier recirculated into the toner replenishing cartridge by the recirculation device.

According to a third aspect of the invention, in the second aspect of the invention, the carrier recovery container is constituted by a mesh-shaped container having a large number of fine holes.

According to the invention of claim 4, claim 2 or 3
In the invention described above, a spiral groove is formed in the inner wall of the carrier recovery container in a direction opposite to the spiral groove formed in the container of the toner supply cartridge.

According to a fifth aspect of the invention, in the third aspect of the invention, the adsorbing member for adsorbing the moisture absorbed by the refluxed carrier or toner is housed in the mesh-shaped carrier collecting container.

According to a sixth aspect of the invention, in the third aspect of the invention, the fine holes provided in the mesh-shaped container trap particles having a specific particle size or more in the refluxed carrier or toner. Then, it was formed in such a size that particles having a specific particle diameter or less, which would not interfere with normal image formation, would pass through.

[0012]

According to the first aspect of the invention, the toner replenishing cartridge is configured such that approximately the same amount of carrier as that replenished in the toner replenishing cartridge at the time of toner end is circulated and remains in the developer recirculation device. It becomes possible to automatically replace a certain amount of developer by replacing the developer.

According to the second aspect of the invention, since the refluxed carrier is recovered in an independent carrier recovery container, the refluxed carrier is mixed with a new carrier in the premix agent in the toner replenishing cartridge. It disappears.

According to the third and sixth aspects of the invention, since the carrier recovery container is in the form of a mesh, the carriers are trapped, and the toner having a sufficiently small diameter so as not to adversely affect the image passes through the mesh. Therefore, it is possible to improve the reuse efficiency of the toner and collect the carrier, dust, aggregated toner, etc. efficiently and without sacrificing the operability.

According to the fourth aspect of the present invention, it is possible to facilitate the movement of the recycled carrier and to make the shape of the carrier recovery container small in diameter and large in capacity.

According to the fifth aspect of the present invention, by placing an adsorbing member in the carrier recovery container, it is possible to adsorb the water contained in the refluxed carrier and toner and also the water contained in the premix agent. Becomes

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claim 1 will be described with reference to FIGS. First, an outline of the overall configuration of the electrophotographic copying machine will be described with reference to FIG. The photoconductor drum 1 is charged by the charging roller 2 and exposed by the LED array 3 as a writing element to form a latent image. This latent image is developed by the developing device 4.
The image is visualized by a magnetic brush formed on the developing roller 5. This magnetic brush is prepared by the developer 9 which is stirred and circulated by the first stirring roller 7 and the second stirring roller 8 in the developing device 6. A toner replenishing cartridge 10 is attached to the developing device 6 including the developing roller 5, the first stirring roller 7, and the second stirring roller 8. The toner replenishing cartridge 10 is filled with a premix agent 11 in which a carrier is mixed.
1 is supplied to the developing device 6 side. The image on the photosensitive drum 1 thus developed is transferred to the paper 13 sent from the pair of registration rollers 12 by the transfer unit 14. In the transfer section 14, an endless transfer belt 15 is wound between drive rollers 16a and 16b, and the sheet 13 after transfer conveyed by the transfer belt 15 is conveyed to a fixing section (not shown) for fixing. Done. On the other hand, the untransferred toner remaining on the surface of the photosensitive drum 1 after the transfer is collected by a cleaning blade 17 and sent to a collecting unit (not shown) by a conveying screw 18. afterwards,
The photoconductor drum 1 is neutralized by the static eliminator 19 and recharged by the charging roller 2, and the same steps are repeated.

A doctor blade 35 may be provided on the inner wall surface of the developing device 6 above the developing roller 5.
With this doctor blade 35, the density of the agent A (described later) attached to the surface of the developing roller 5 (thickness of the magnetic brush)
Can be made uniform.

Next, the developing device 4 forming the main part of this embodiment.
The configuration will be described with reference to FIG. The premix agent 11 in the toner supply cartridge 10 is sent to the developing device 6 side from the opening 21 when the cap 20 attached to the cartridge is removed. That is, the feed groove 22 as a spiral convex groove is formed on the inner wall of the container of the cylindrical toner supply cartridge 10, and the premix agent 11 is rotated by rotating the entire container in the X direction.
Is supplied to the developing device 6 through the opening 21. When the premix agent 11 is replenished in the developing device 6, the increased amount of carriers overflows in the developing device 6, and the overflowed agent A (the carrier, the premix agent 11, etc. (Including) is sent to the discharge screw 23 that is the first transport path, and is sent to the cylindrical container 26 via the second transport path 24 and the third transport path 25 partially inserted in the toner replenishment cartridge 10. The
The toner reaches the discharge port 26a at the end portion thereof, and then flows into the toner supply cartridge 10 again. The discharge screw 23, the second transport path 24, and the third transport path 25 are
The developer recirculation device 27 is configured. In the developing device 6,
The developer 9 (toner, carrier, premix agent 11) is circulated. A cleaning toner transport path 29 is connected to the transport screw 18.

The cylindrical container 26 here is provided on the central axis of the container of the toner supply cartridge 10, and the cylindrical container 26 is fitted in the third conveying path 25. As a result, the position in the toner supply cartridge 10 where the overflowed agent A is circulated is substantially at the center of the container. When the toner supply cartridge 10 is rotated about its axis, the cylindrical container 26
The toner is replenished from the discharge port 28 on the end face of the.

In such a structure, before describing the operation of the developer recirculation device 27, first, the developer recirculation device 2 is first described.
Reasons for establishing a toner recycling system such as 7
That is, the reason why the collected toner is not mixed with the new toner in the related art, but the toner can be reused in the present invention will be described. In recent years,
Advances in toner manufacturing technology are making it possible to easily manufacture toner having a uniform particle size. This allows
If the shape is uniform, the physical properties and the like are also uniform, and for example, the pressure of the cleaning blade 17 can be set lower than in the conventional case. Therefore, from such a reason, the probability that the toner will be physically destroyed or aggregated at the time of collection is reduced, and as a result, separation at the time of reuse is facilitated, and image deterioration is less likely to occur. The toner recycling system as in the present invention is provided. The operation of the developer recirculation device 27 will be mainly described below.

The amount of the carrier contained in the premix agent 11 in the toner replenishing cartridge 10 is such that the developer 9 is retained even if the number of copies that can be copied by the toner replenished by the toner replenishing cartridge 10 is repeated once. Select a carrier weight percentage that does not degrade. Then, when the premix agent 11 is replenished from the toner replenishing cartridge 10 into the developing device 6,
The increased amount of carriers overflows. Due to this overflow, the discharge screw 23 (first transport path)
The agent A sent from the above reaches the discharge port 28 via the second transport path 24, the third transport path 25, and the cylindrical container 26, and flows into the toner supply cartridge 10 again. As a result, the amount of the agent A replenished as the premix agent 11 is
At the time of toner end, it means that the toner is held in the toner supply cartridge 10. After the transfer by the photosensitive drum 1, the collected toner collected in the cleaning toner conveying path 29 via the conveying screw 18 is accumulated in a collected toner container (not shown).

As described above, by providing the path as the developer recirculation device 27 for recirculating the carrier replenished in the developing device 6 as the premix agent 11, the toner replenishing cartridge 10 is automatically replaced by a constant amount. A certain amount of the developer 9 is replaced, which eliminates the need for regular replacement of the developer 9. Further, as the toner replenishing cartridge 10, a cylindrical container having a spiral feed groove 22 formed on its inner wall is used, and the recirculation path of the carrier is selected in the vicinity of the rotation center of the container to prevent toner replenishment. Therefore, the automatic replacement of the developer 9 can be realized without sacrificing the toner capacity and operability.

Next, an embodiment of the present invention described in claims 2 and 4 will be described with reference to FIG. The description of the same parts as those in the first aspect of the present invention will be omitted, and the same reference numerals will be used for the same parts.

Here, the shape of the cylindrical container connected to the subsequent stage of the third conveying path 25 of the developer recirculation device 27 is changed. That is, the continuous cylindrical container means the carrier recovery container 30 provided near the center of the cylinder of the toner supply cartridge 10, and the developer recirculation device 2
The carrier recirculated in the toner replenishing cartridge 10 is trapped by 7. This carrier recovery container 30 is
The container has a volume sufficient to receive the carrier to be refluxed, and a feed groove 31 as a groove having a convex shape and a spiral shape is formed on the inner wall of the container. This feed groove 3
1 is formed in the direction opposite to the feed groove 22 formed on the inner wall of the container of the toner supply cartridge 10. In addition,
Instead of forming the feed groove 22 on the inner wall of the container as described above, a spiral thin metal wire may be inserted.

In such a structure, the agent A overflowing in the developing device 6 is recirculated into the carrier recovery container 30 from the third conveying path 25 of the developer recirculation device 27.
By rotating the toner supply cartridge 10 in the X direction,
The agent A recirculated into the carrier recovery container 30 has a feed groove 31.
It moves in the Y direction according to the direction of. Then, finally, the developer 9 having a volume corresponding to the carrier replenished in the premix agent 11 is held in the carrier recovery container 30. As a result, by replacing the entire toner replenishing cartridge 10, the carrier collecting container 30 is also replaced at the same time, and the toner can be collected.

As described above, the carrier recovered by the developer recirculation device 27 is an independent carrier recovery container 30.
Since the new carrier in the premix agent 11 and the recirculated carrier are not mixed with each other, the agent A can be reliably exchanged automatically. Further, by forming the spiral feed groove 31 in a direction different from the feed groove 22 of the toner supply cartridge 10 in the carrier collection container 30 holding the carrier, the carrier collection container 30 can have a small diameter and a large capacity. it can.

Next, an embodiment of the present invention described in claims 3, 5 and 6 will be described with reference to FIG. In addition, claims 1, 2,
The description of the same parts as those of the invention described in 4 is omitted, and the same parts are denoted by the same reference numerals.

Here, the carrier recovery container 30 is formed of a mesh-shaped container having a large number of fine holes (not shown). In this case, the fine holes provided in the mesh-shaped container trap the carrier that is a particle having a specific particle size or more among the refluxed carrier and the developer 9 of the toner, and a normal image having a specific particle size or less is obtained. It is formed in a size that allows the toner particles, which are particles that do not hinder the formation, to pass through. This mesh carrier recovery container 30
Has a two-piece structure that can be easily removed from the toner supply cartridge 10. Further, the carrier recovery container 30 accommodates a desiccant 32 as an adsorbing member for adsorbing the recirculated carrier and the moisture absorbed by the toner, and a crushed sphere 33.

A fourth transport path 34 extends from the cleaning toner transport path 29, and the fourth transport path 34 is provided.
Is connected to the second transport path 24. As a result, the carrier recovery container 30 includes the discharge screw 2 of the developing device 6.
Not only the carrier from 3, but also the discharged toner remaining after the transfer is collected. Therefore, the developer recirculation device 27 here includes the discharge screw 23 and the second transport path 24.
The fourth transport path 34 is added to the third transport path 25.

Further, in such a cleaning unit, not only the collected toner but also the residual toner on the transfer belt 15 is transferred from the cleaning toner conveying path 29 to the fourth portion.
It can be reused and collected by being merged into the passage of the transport path 34.

In such a structure, the developer 9 and the discharged toner that have overflowed become the agent A finally.
It is collected from the transport path 25 into the carrier collection container 30. This agent A is conveyed in the Y direction by the feeding groove 31, and passes through the mesh-shaped container in the middle thereof. At this time, a sufficiently fine toner (suitable for reuse that has not been coarsened or stuck) passes through the mesh to the outside, and enters the toner replenishing cartridge 10 for reuse. On the other hand, carriers, dust, fibers such as paper, coarsened toner, and the like are captured in the carrier collection container 30 without going out from the mesh. Then, finally, by replacing the toner supply cartridge 10, the carrier collecting container 30 is also replaced, so that the toner can be reused and unnecessary aggregated toner and the like can be collected.

Further, the desiccant 32 has a function of adsorbing moisture absorbed by the refluxed carrier or toner. The crushed balls 33 have a function of promoting the passage of toner from the mesh to the outside. In this case, silica gel or rice grains can be used as the desiccant 32. Further, as the crushed sphere 33, a metal or glass sphere can be used.

As described above, since the carrier recovery container 30 has a mesh shape, it traps carriers, dust, coarsened or adhered toner, etc., and returns small-sized toner to the toner replenishing cartridge 10 for reuse. be able to. Therefore, by replacing the toner supply cartridge 10 for each toner end, a part of the carrier in the developing device 6 is replaced with a new one, and at the same time, most of the discharged toner can be reused. The efficiency can be increased. Further, by disposing the desiccant 32 in the carrier recovery container 30, it is possible to adsorb the water in the recirculated carrier and the toner, and at the same time, it is possible to adsorb the water in the premix agent 11 as well. It can also improve the fluidity and electrostatic properties of the.

[0035]

According to the first aspect of the present invention, a toner replenishing cartridge is filled with a premix agent mixed with a carrier, and the filled premix agent is developed in accordance with a decrease in toner concentration in the developer. In the dry two-component type developing device for replenishing to the side, a developer recirculation device for recirculating the carrier overflowed by replenishment of the premix agent from the developing device to the toner replenishment cartridge side is provided. At the end of the toner, almost the same amount of carrier that was replenished in the toner replenishment cartridge will flow back through the developer recirculation device and remain, which will automatically replace a fixed amount of developer by replacing the toner replenishment cartridge. Since the toner can be replaced, the periodical replacement of the developer is unnecessary.

In a second aspect of the present invention, a toner replenishing cartridge is filled with a premix agent mixed with a carrier, and the filled premix agent is sent to the developing device side in accordance with a decrease in toner concentration in the developer. In a dry two-component developing device for replenishing, a developer recirculation device for recirculating the carrier overflowed by replenishment of the premix agent from the developing device to the toner replenishment cartridge side is provided. Since the carrier recovery container for trapping the carrier recirculated in the toner replenishing cartridge by the recirculation device is provided, the recirculated carrier is recovered in the independent carrier recovery container, and the recirculated carrier is stored in the toner replenishing cartridge. Will not mix with the new carrier in the premix, It is capable of performing a reliable exchange of image agent.

According to a third aspect of the present invention, in the second aspect of the present invention, the carrier recovery container is constituted by a mesh-shaped container having a large number of fine holes formed therein. Can be returned to the toner supply cartridge and reused.

According to a fourth aspect of the present invention, in the invention according to the second or third aspect, a spiral groove formed in the inner wall of the carrier recovery container in a direction opposite to the spiral groove formed in the container of the toner supply cartridge. Since the carrier is formed, the refluxed carrier can be easily moved, and the shape of the carrier recovery container can be made small and have a large capacity.

According to a fifth aspect of the present invention, in the third aspect of the present invention, since the adsorbing member for adsorbing the moisture absorbed by the recirculated carrier or toner is accommodated in the mesh-shaped carrier recovery container, the recirculation is performed. In addition to adsorbing the water contained in the carrier and the toner thus prepared, the water contained in the premix agent can also be adsorbed, thereby improving the fluidity and electrostatic characteristics of the toner.

According to a sixth aspect of the present invention, in the third aspect of the invention, the fine holes provided in the mesh-shaped container trap particles having a specific particle size or more in the refluxed carrier or toner. However, since it is formed in a size that allows particles having a specific particle size or less, which does not hinder normal image formation, to pass through, the carrier is trapped, and the toner having a sufficiently small diameter that does not adversely affect the image is It is possible to select to pass through the mesh, thereby improving the reuse efficiency of the toner, and moreover, it is possible to collect the carrier, dust, aggregated toner, etc. efficiently and without sacrificing the operability. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a developing device according to the first aspect of the invention.

FIG. 2 is a front view showing the configuration of an electrophotographic copying machine.

FIG. 3 is a sectional view showing the structure of a developing device according to the second and fourth aspects of the invention.

FIG. 4 is a cross-sectional view showing the structure of a developing device according to a third aspect of the invention.

[Explanation of symbols]

 4 Developing Device 6 Developing Device 9 Developer 10 Toner Replenishing Cartridge 11 Premixing Agent 27 Developer Refluxing Device 30 Carrier Recovery Device 31 Groove 32 Adsorption Member

Claims (6)

[Claims] 1. A dry type toner replenishing cartridge is filled with a premix agent mixed with a carrier, and the filled premix agent is replenished to a developing device side in accordance with a decrease in toner concentration in the developer. A developing device of a component type, comprising a developer recirculation device for recirculating the carrier overflowed by replenishment of the premix agent from the developing device to the toner replenishment cartridge side. 2. A dry-type toner replenishing cartridge is filled with a premix agent mixed with a carrier, and the filled premix agent is replenished to a developing device side in accordance with a decrease in toner concentration in the developer. In the component type developing device, a developer recirculation device for recirculating the carrier overflowed by the replenishment of the premix agent from the developing device to the toner replenishment cartridge side is provided,
A developing device comprising a carrier recovery container for trapping the carrier recirculated into the toner replenishing cartridge by the developer recirculating device. 3. The developing device according to claim 2, wherein the carrier recovery container is a mesh-shaped container in which a large number of fine holes are formed. 4. The developing device according to claim 2, wherein a spiral groove in a direction opposite to the spiral groove formed in the container of the toner supply cartridge is formed on the inner wall of the carrier recovery container. apparatus. 5. The developing device according to claim 3, wherein an adsorbing member for adsorbing the moisture that is absorbed by the refluxed carrier or toner is housed in a mesh-shaped carrier recovery container. 6. The fine holes provided in the mesh-shaped container trap particles having a specific particle size or more in the refluxed carrier or toner, and interfere with normal image formation having a specific particle size or less. 4. The developing device according to claim 3, wherein the developing device is formed in a size that allows particles of a certain size to pass therethrough.