JPH0895362A - Developing device - Google Patents

Abstract

PURPOSE: To provide a developing device capable of facilitating the maintenance of a developing device and the replenishment/replacement of developer, and enhancing the reliability of the developing device (reduction of down time) by prolonging the life of the developer in the developing device. CONSTITUTION: Among the developer 101 contained in a developing unit 105, the redundant (exhausted) developer 101' contained over the normal quantity is transferred to the redundant developer containing part of a developer containing member 125 containing the replenishing developer 102. In the developer containing member 125, the replenishing developer containing part for containing the fresh replenishing developer replenished to the developing part and the redundant developer containing part for containing the redundant developer transferred from the thus the new/old developer is separately contained without mixing in each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an image forming apparatus using an electrophotographic system.

[0002]

2. Description of the Related Art As a kind of developing device for an image forming apparatus using an electrophotographic system such as a copying machine or a printer, it is used as a developer for visualizing a latent image formed on a latent image carrier. ,
A developing device using a premix developer (two-component developer), which is a mixture of toner and carrier, is known. As is well known, in this type of developing device, as the image forming operation (copy or print) of the latent image formed on the latent image carrier is repeatedly executed, the development unit accommodated in the developing unit Since the toner in the developer is successively consumed, the capacity of the carrier in the developer gradually increases. Further, in the developing device of this type, when the image forming operation is continuously executed in the state where the carrier is still increased as described above, the carrier in the developing device is gradually fatigued, and, for example, toner filming is performed. , Crushing, breakage of the coat film applied on the surface of the carrier, etc., and the developing ability of the developer is significantly reduced.

Heretofore, as means for solving the problems associated with the increase of the carrier in the developer, (1) a developing portion and a fixed amount of carrier in the developing portion according to a predetermined developing time or a predetermined copying amount. For supplying a toner to the developing unit by the signal, a detector for detecting a change in the ratio of the carrier and the toner in the developer, and a signal for supplying the toner to the developing unit. An "electrophotographic developing device" described in JP-A-51-13249, which has a discharging means. (2) In a developing device that supplies an additional developer containing a carrier and toner to the developer in the developing device, a housing provided with an outlet port for discharging the developer, and the carrier and toner are provided outside the housing. Means to release,
In response to the detection means indicating that the amount of developer is equal to or greater than a predetermined amount, the device has means for detecting the amount of developer in the housing chamber and means for sealing the outlet port of the housing. The "developing device" described in Japanese Patent Application Laid-Open No. 4-353881, in which the sealing means discharges the developer from the outlet port to reduce the amount of the developer inside the housing. (3) The developing device is provided with a volume ratio changing means for changing the volume ratio after toner supply so that the toner storage portion is small and the toner recovery portion is large, so that the used toner can be used without increasing the overall volume. A "toner cartridge" described in Japanese Patent Laid-Open No. 63-298370, which reliably prevents mixing with new toner. (4) By disposing the toner replenishment section with the toner storage section arranged inside the photosensitive drum and the means for conveying the toner in the toner storage section to the developing device, an arrangement space for the toner storage section inside the main body is provided. A "copying device" described in Japanese Utility Model Application Laid-Open No. 64-30562, which is omitted to reduce the size of the device. Have been proposed.

[0004]

However, in the above-mentioned "electrophotographic developing device" described in Japanese Patent Application Laid-Open No. 51-13249, the carrier supply means is provided separately from the toner supply means, and the developer is further added. Since it is necessary to newly provide a discharging means / member for discharging and a container for storing the discharged developer, there is a problem that the entire image forming apparatus has a complicated structure and becomes large in size and high in cost.

Further, the above-mentioned conventional Japanese Patent Laid-Open No. 4-353881.
Similarly, in the case of the "developing device" described in the publication, it is necessary to newly provide a discharging means / member for discharging the developer and a container for storing the discharged developer, so that the entire image forming apparatus has a complicated structure. However, there is a problem that the size becomes large and the cost becomes high.

Further, the above-mentioned conventional Japanese Patent Laid-Open No. 63-29837.
In the "toner cartridge" described in Japanese Patent No. 0, the purpose is to return the toner collected from the photoconductor cleaner to the toner storage portion, and therefore the used developer cannot be returned to the toner storage portion.

Further, the above-mentioned prior art utility model Japanese Utility Model Laid-Open No. 64-30562.
In the "copying device" described in the publication, toner supply, storage, and
This is related to recovery, and although the device can be downsized, the used developer cannot be returned to the toner storage portion.

The present invention has been made in view of the above points, and an object thereof is to facilitate the maintenance of the developing device by extending the life of the developer in the developing device and to replenish and replace the developer. It is an object of the present invention to provide a developing device capable of facilitating the development of the developing device and improving the reliability of the developing device (reducing downtime). Another object of the present invention is to provide a developing device that can solve the above problems without providing a complicated carrier and toner supplying means and a discharging means for these in the developing device.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention has a developing section for accommodating a two-component developer in which toner and carrier are mixed, and is consumed in the developing section. A developer accommodating means for accommodating the replenishment developer to be replenished to the developing portion according to the amount of the developer, and an excess developer transferring means for transferring an excessive developer from the developing portion to the developer accommodating means. The configuration is provided.

In the present invention, in order to achieve the above object, a two-component developing system is used as the developing system. Further, as the developer to be replenished, a two-component developer, which is commonly called a premix developer, which replenishes the carrier together with the toner, is used. Further, a developer concentration detecting means for detecting whether or not the developer concentration contained in the developing portion is a prescribed amount, and the premix developer is supplied to the developing portion in response to a detection signal of the developer concentration detecting means. It has a developer supplying means for performing.

[0011]

According to the present invention, when the storage amount of the developer stored in the developing unit exceeds the specified amount, the excess developer automatically stores new developer for replenishment from the developing unit. Transferred to the means. The developer accommodating means includes a first accommodating section for accommodating a new replenishment developer to be replenished to the developing section and a second accommodating section for accommodating the excess developer transferred from the developing section. Independently arranged, old and new developers are stored without being mixed with each other. As a result, the developer having a constant amount (specified amount) and a specified developer concentration is always stored in the developing device.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the developing device of the present invention. An image forming apparatus equipped with this developing device forms an image by a well-known electrophotographic process.

That is, in FIG. 1, an electrostatic latent image is formed on the surface of the latent image carrier (photosensitive drum) 1 by being uniformly charged by the charger 3 and irradiated with the exposure image 2. It This electrostatic latent image is made into a toner image (visualized) by the developing device 100, and then transferred onto a transfer paper (not shown) by a transfer device not shown. The transferred transfer paper on which the toner image has been transferred is sent to a fixing device (not shown) and discharged as a copy or a printed matter onto a tray outside the apparatus. On the other hand, the latent image carrier 1 after transferring the toner image
After removing foreign matter such as residual toner and paper dust adhering to the surface by a cleaning device (not shown), the residual charge is removed by a charge remover (not shown).

The developing device 100 in this embodiment shows an example using a two-component magnetic brush developing system. Here, the developer 101 is composed of a two-component developer including a toner and a carrier, and the mixing ratio of the toner and the carrier is usually 1.5 to 5.0 toner weight%. . Further, the supplied developer 102 is composed of toner and carrier as in the case of the developer 101, and the mixing ratio of the toner and carrier is usually 70 to 90% by weight.

As the developing roller 103, a known developing roller having a magnet inside is used. This developing roller 1
The developer 101 supplied to the surface of No. 03 is regulated by the developer regulating member 104 so as to always have an appropriate amount.

The developer 101 is transferred and circulated to the developing roller 103 in the developing container 105 while being stirred by the stirring members 106 and 107, the agent guide member 108, and the agent transfer screw 109. In addition, this developer 10
The density of 1 (mixing ratio of toner and carrier) is detected by the developer density detector 120. As the developer concentration detector 120, a conventionally well-known detector for detecting the magnetic permeability of the developer 101 is most known.

In FIG. 1, when the image forming operation (copy, print) progresses a plurality of times and the developer concentration in the developing container 105 decreases, the developer supplying member 110 is rotated by a drive motor (not shown) and the like. A fixed amount of the supplied developer 102 is supplied into the developing container 105 by a groove portion provided in a part of the periphery of the developer supplying member 110, and the developing container 1
The concentration of the developer 101 in 05 is maintained at a predetermined prescribed concentration. Here, the stored supply developer 102 is transferred to the developer supply member 110 by the transfer / stirring member 111.

By the way, in the image forming apparatus using the premix developer of this type, as described above, as the image forming operation (copy or print) is repeatedly executed, the image is stored in the developing container 105. The toner in the developing agent 101 is successively consumed, and the capacity of the carrier in the developing agent gradually increases. When the image forming operation is continuously executed in the state where the carrier is still increased, the carrier in the developing container 105 is gradually fatigued and, for example, is subjected to toner filming, crushing, and the surface of the carrier. The coat film is damaged and the developing ability of the developer 101 is significantly impaired.

Here, if the increased carrier is discharged to the outside of the developing container 105 at any time and a new developer (supplying developer 102) is constantly supplied, the developer 10 in the developing device 100 may be supplied.
It is possible to always maintain the developing capacity of 1 at a predetermined level. The present invention provides a developing device capable of reliably discharging the excess developer 101 in the developing container 105, which is impairing the developing ability, to the outside of the developing container 105 based on this basic principle.

In the developing device 100 according to the present invention, as shown in FIG. 1, a dam portion (developer 10) is formed in a part of the developing container 105.
No. 1 level control unit) 105a is provided, and when the amount of the developer 101 replenished in the developing container 105 increases,
The surplus (fatigue) developer 101 ′ is the dam portion 105 a.
Overcoming (overflowing) the developer collecting section 12
Guided to 1.

The surplus (fatigue) developer 101 'which has passed over the dam portion 105a is discharged by the discharge screw 122 attached to the developer recovery portion 121 and the transfer member 123.
Thus, as shown in FIG. 3, the excess developer accommodating portion provided in a part of the developer accommodating member (developer cartridge) 125 passes through the introduction hole portion 124a provided in a part of the developer supply container 124. It is stored in 126a.

As shown in FIG. 2, the developing portion of the developing device 100 includes a developing container 105, front and rear developing container side plates 127,
It is supported by 128. The developing roller 103, the stirring members 106 and 107, and the agent transfer screw 109 are laterally supported rotatably between the front and rear developer container side plates 127 and 128, respectively. The developing roller 103, the stirring members 106 and 107, and the agent transfer screw 109 are connected to each other by gears so as to rotate together, and are rotationally driven by a developing drive motor 130.

On the other hand, the developer supply member 110 and the transfer / stirring member 111 are transferred / removed by a replenishment motor 131.
It is driven via the stirring drive gear 132 and another gear that meshes with this. In addition, the discharge screw 122
Is driven via a gear train 122a arranged on one end surface of the stirring member 106 (outer surface of the front developing container side plate 127). The discharge screw 122 may be driven by a dedicated motor. The discharge screw 122 is rotatably inserted into the transfer member 123, and the rotation of the discharge screw 122 collects and transfers the surplus (fatigue) developer 101 ′ through the transfer member 123.

The transfer / stirring member 111 is disposed inside the developer accommodating member 125, as shown in FIGS. In FIG. 2, when the transfer / stirring drive gear 132 is rotated by the replenishment motor 131, as shown in FIG.
The drive joint 133 provided coaxially with the transfer / stirring drive gear 132 is driven. As a result, this drive joint 133
The driven joint 134 attached to the end portion of the transfer / stirring member 111, which is engaged with, is driven, and the transfer / stirring member 111 is rotated in a direction for supplying the replenishment developer 102.

As shown in FIG. 5, the developer accommodating member 125 includes a surplus developer accommodating portion 126a for accommodating an excess (fatigue) developer 101 'and a replenishment development for accommodating the replenishment developer 102. Two storage units, the agent storage unit 126b and the storage unit 126b, are provided independently of each other, and the above-described transfer / stirring member 111 is disposed in the replenishment developer storage unit 126b. Further, as shown in FIG. 4, a part of the outer peripheral portion of the developer accommodating member 125 is connected to the introduction hole portion 135 communicating with the surplus developer accommodating portion 126a and the replenishment developer accommodating portion 126b. Two cutout holes for the communicating replenishment hole portion 136 are provided respectively.

In the excessive developer accommodating portion 126a of the developer accommodating member 125, as described above, the excessive (fatigue) developer 101 'which has passed over the dam 105a is discharged to the developer collecting portion 121. By the screw 122 and the transfer member 123, the toner is transferred and stored through an introduction hole portion 124a provided in a part of the developer supply container 124 and an introduction hole portion 135 communicating with the excess developer storage portion 126a.

On the other hand, the replenishment developer 102 stored in the replenishment developer storage portion 126b of the developer storage member 125 is
By the rotation of the transfer / stirring member 111, the transfer / stirring member 111 is transferred to the developer supply member 110 through the supply hole portion 136 communicating with the supply developer storage portion 126b.
By the rotation of 0, a predetermined amount is replenished in the developing container 105 according to a predetermined copy (print) amount. This allows
The concentration of the developer 101 in the developing container 105 is maintained at a predetermined prescribed concentration.

As described above, the excess developer accommodating portion 126a and the replenishment developer accommodating portion 126 in the developing device of this embodiment are provided.
b is provided integrally with one developer accommodating member 125. Further, the developer storage member 125 is provided in the developer supply container 12 when the supply developer 102 stored in the supply developer storage portion 126b is exhausted.
4, the developer accommodating member 125 is pulled out to the front side of the developing device 100 and is replaced with a new developer accommodating member 125. Therefore, in the developing device of the present embodiment, by exchanging the developer accommodating member 125, the surplus (fatigue) developer 101 ′ collected from the developing section is also taken out of the machine.

By the way, a color image forming apparatus generally requires a plurality of developing devices, and the image occupying area (area of a pattern) of an original to be copied (or printed).
Is large, and the amount of toner consumed is very large as compared with an apparatus that forms only a normal monochrome image. Therefore, in this type of color image forming apparatus, since the type and the amount of the surplus (fatigue) developer to be discharged also increase, if the developing device of the present invention is used in such a color image forming apparatus, It is more effective and effective in terms of its structure and image forming process.

[0030]

According to the present invention, in claim 1, the maintenance of the developing device can be facilitated and the reliability can be improved (downtime can be reduced), and the developer can be replenished and replaced. It can be facilitated and stable development characteristics can be maintained.

According to the second aspect, in addition to the effect of the first aspect, it is possible to maintain stable development (developer) characteristics with time, and it is possible to reliably replace the old and new developers.

According to the third aspect, in addition to the effect of the first aspect, it is possible to maintain stable development (agent) characteristics with time.

According to a fourth aspect, in addition to the effect of the first aspect, the developer accommodating means can be simplified, the image forming apparatus and the developing apparatus can be simplified, and mixing of old and new developer can be prevented. In addition, the replenishment and recovery of the developer can be facilitated.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a developing device of the present invention.

FIG. 2 is a schematic perspective view of a developing device of the present invention.

FIG. 3 is a schematic perspective view of a developer accommodating portion in the developing device of the present invention.

FIG. 4 is a schematic perspective view of a developer accommodating member in the developing device of the present invention.

FIG. 5 is a schematic sectional view of a developer accommodating member in the developing device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Latent image carrier (photosensitive drum) 2 Exposure image 3 Charging device 100 Developing device 101 Developer 101 'Excessive (fatigue) developer 102 Replenishment developer 103 Developing roller 104 Developer regulating member 105 Developing container 105a Weir portion 106 , 107 stirring member 108 agent guide member 109 agent transfer screw 110 developer supply member 111 transfer / stirring member 120 developer concentration detector 121 developer recovery section 122 discharge screw 123 transfer member 124 developer supply container 125 developer storage member 126a Excess developer storage 126b Replenishment developer storage 127 Front development container side plate 128 Rear development container side plate 130 Development drive motor 131 Supply motor 132 Transfer / stirring drive gear 133 Drive joint 134 Driven joint 135 Inlet hole 136 Supply hole

Claims (4)

[Claims] 1. A developing section containing a two-component developer containing a mixture of toner and carrier, and a replenishing developer replenished to the developing section according to the amount of developer consumed in the developing section. A developing device comprising: a developer accommodating means for accommodating the developer; and an excess developer transferring means for transferring an excessive developer from the developing section to the developer accommodating means. 2. A developer concentration detecting means for detecting a change in the ratio of toner and carrier in the developer in the developing section and issuing a signal, and a developer prepared by mixing a fixed amount of toner and carrier by the signal. 2. The developing device according to claim 1, further comprising: a developer replenishing unit that discharges a predetermined amount of developer to the developing unit according to a predetermined image forming amount. 3. The mixing ratio of the toner of the developer and the carrier in the developing section is 1.5 to 5.0% by weight, and the mixing ratio of the toner of the replenishing developer and the carrier is 70.
The developing device according to claim 1, wherein the developing device has a toner content of 90 to 90% by weight. 4. The developer accommodating means comprises a first accommodating section for accommodating a new replenishment developer to be replenished to the developing section, and a second accommodating section for accommodating the excess developer transferred from the developing section. 2. The developing device according to claim 1, wherein the parts and the parts are independently provided.