JP3127938B2 - Image forming device - Google Patents

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 such as a copying machine, a facsimile, a printer, and the like. More specifically, a cleaning device collects toner remaining on an image carrier after transfer, and conveys the toner to a developing device. And an image forming apparatus for reuse.

[0002]

2. Description of the Related Art At present, the destruction of the environment and the increase of industrial waste have become major problems in the world. Resource saving,
Reuse has come to the fore. To cope with the problem of increasing industrial waste, an image forming apparatus using an electrophotographic method is no exception, and some industrial waste is generated. For example, when considering the image output process of an image forming apparatus using an electrophotographic method, the charging device uniformly charges the surface of the image carrier, and then forms an electrostatic latent image from the exposure device. A toner is supplied to the electrostatic latent image by a developing device, visualized on the surface of the image carrier, transferred to a transfer paper by a transfer device, and an image is output. Then, residual toner remaining on the surface of the image carrier during transfer is removed by a cleaning device. Further, in the area other than the area of the electrostatic latent image, the toner adhered to the surface of the image carrier and not transferred is also removed by the cleaning device. Conventionally, the toner removed and collected by the cleaning device (hereinafter, referred to as a collected toner) is usually discarded. Therefore, a technology for reducing industrial waste such as the collected toner is currently being developed.

Recently, in order to effectively reuse the collected toner collected by the cleaning device, it has been proposed to return the collected toner to a developing device and reuse the collected toner. However, when the collected toner is reused, the unused toner from the toner cartridge (hereinafter referred to as “unused toner”) and the collected toner are mixed in the developing device, so that a background stain is generated on the image. However, there have been problems such as an increase in the sharpness of the image, deterioration of the sharpness of the image, and deterioration of toner scattering from the developing device into the image forming device. Investigation of these causes revealed that the rising characteristics, fluidity, transferability, cleaning properties, etc. of the triboelectric charge of the recovered toner were deteriorated as compared with the unused toner.

[0004] Conventionally, as this type of apparatus, there is an apparatus which directly feeds collected toner collected by a cleaning device into unused toner in a toner storage device to homogenize the toner to be supplied to a developing device. Although it is known (for example, see Japanese Patent Application Laid-Open No. 58-196571), it does not satisfy the image quality currently required in the market.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the following:
It is an object of the present invention to provide an image forming apparatus capable of obtaining a high-quality image excellent in sharpness without background contamination and capable of reusing collected toner without causing toner scattering or cleaning failure.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a conveyance control means for selectively conveying a cleaning device to a collected toner storage device, and the collected toner storage device. And a collected toner replenishing control means for replenishing the collected toner from the developing device to the inside of the developing device when the conveyance is stopped.

According to a second aspect of the present invention, there is provided a means for detecting the temperature of the collected toner, and replenishment of the collected toner into the developing device when the temperature of the collected toner falls below a predetermined temperature. And a collected toner replenishment control means for performing the above operation.

According to a third aspect of the present invention, there is provided a means for detecting the temperature of the collected toner, a means for detecting the temperature in the developing device, and wherein the temperature of the collected toner is substantially the same as the temperature of the toner in the developing device. And recovering toner replenishment control means for replenishing the recovered toner into the developing device when the temperature becomes high.

Further, the invention according to claim 4 is characterized in that a means for mixing an additive into the collected toner in the collected toner storage device is provided before supplying the collected toner to the developing device. Things.

According to a fifth aspect of the present invention , a toner replenishing roller is provided as a collected toner charging means for charging the collected toner in the collected toner storage device to the same polarity as the toner in the developing device.
The contacting auxiliary roller and the charging polarity of the toner in the developing device
DC that applies a DC bias voltage of the same polarity to the auxiliary roller
A power supply is provided.

The invention according to claim 6 is characterized in that a means for applying an AC voltage to the collected toner in the collected toner storage device is provided.

Further, the invention of claim 7 is characterized in that a means for cooling the collected toner conveying device is provided.

[0013]

According to the first aspect of the present invention, even when the transfer control unit and the collected toner replenishment control unit perform continuous feeding of the transfer paper, the collected toner in the collected toner storage device is also used. Can be sufficiently attenuated so that there is no difference in electrostatic characteristics (charge amount, charge polarity, etc.) between the toner in the developing device and the collected toner.

According to the second aspect of the present invention, the temperature of the collected toner is increased by the means for detecting the temperature of the collected toner and the means for controlling the replenishment of the collected toner. Even when the rising characteristics of the toner are deteriorated, the temperature of the collected toner in the collected toner storage device can be reduced, so that there is no difference in the electrostatic characteristics between the toner in the developing device and the collected toner. To

According to a third aspect of the present invention, the means for detecting the temperature of the collected toner, the means for detecting the temperature of the toner in the developing device, and the means for controlling the supply of the collected toner make the collected toner a high temperature. Therefore, even when a temperature difference from the temperature of the toner in the developing device, that is, a difference in resistance value occurs, the amount of charge, that is, the charging amount, between the collected toner and the toner in the developing device due to frictional charging in the developing device. Make the characteristics the same.

Further, in the invention according to claim 4, the means for mixing the additive is used to improve the fluidity and prevent sticking due to stress in the developing device or stress in the transport device during development. Even if an additive for the toner is buried in the mother body of the collected toner, the collected toner and the toner in the developing device have the same charging characteristics and fluidity.

Further, in the invention according to claim 5, even if the collected toner is electrostatically fatigued by the collected toner charging means and the charging polarity is not constant, the same as the toner in the developing device. It is weakly charged to a polarity to compensate for the deterioration of the rising characteristic of the triboelectric charging of the collected toner so that the collected toner and the toner in the developing device have the same electrostatic characteristics.

Further, in the invention according to claim 6, the means for applying an AC voltage to the collected toner allows the collected toner to be electrostatically fatigued even when the charged polarity is not constant. The charge of the toner is eliminated to compensate for the deterioration of the rising characteristic of the triboelectric charging of the collected toner so that the collected toner and the toner in the developing device have the same electrostatic characteristics.

Further, in the invention according to claim 7, the temperature of the collected toner conveying device is lowered by means for cooling the collected toner conveying device, so that the collected toner is aggregated and adhered to the collected toner conveying device. Try not to happen.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter, referred to as a copying machine) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of a copying machine according to the first embodiment. First, an outline of the entire copying machine will be described. A reversal developing system is used in which, for example, a negatively charged organic photoreceptor is used as a photosensitive layer of the photoreceptor drum 1 as an image carrier, and a two-component developer containing, for example, a negatively charged toner is used as a developer. The surface of the photosensitive drum 1 rotates in the direction of the arrow, and is first uniformly charged by the charging charger 2, and a laser beam corresponding to image information is main-scanned in the axial direction of the photosensitive drum 1 by an exposure optical system (not shown).
Sub-scanning is performed by the rotation of the photosensitive drum 1. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 1. This electrostatic latent image is developed by the developing unit 4 as a developing device to become a toner image. As the surface potential on the surface of the photosensitive drum 1 during development, for example, the image background potential (dark portion potential) VD is set to about -800 V, and the image portion potential (light portion potential) VL is set to about -100 V. The negatively charged toner adheres to the image portion with a potential difference from the developing bias potential VB of about -600 V, and the electrostatic latent image is developed. The toner image is transferred to the transfer paper P under the action of the transfer charger 5.
Is transferred to The transfer paper P is separated from the photosensitive drum 1 under the action of the separation charger 6, and is fixed by a fixing device (not shown), thereby completing printing. On the other hand, the toner remaining on the surface of the photosensitive drum 1 after the transfer is
The toner is removed and collected by the cleaning device 7 (hereinafter, the collected toner is referred to as collected toner). Thereafter, the electric charge remaining on the surface of the photosensitive drum 1 is removed from the charge removing lamp 9.
And the surface of the photosensitive drum 1 is prepared for the next image formation.

In order to control the toner supply of the developer in the developing unit 4 within a predetermined range, an electrostatic latent image corresponding to the reference density pattern is provided outside the image area on the surface of the photosensitive drum 1. Is formed into a toner image by the developing unit 4. In order to detect the density of the toner image corresponding to the reference density pattern and to output a signal corresponding to the detected density, the developing unit 4 close to the surface of the photosensitive drum 1 near the surface of the photosensitive drum 1 is output downstream. At a position, a toner image density sensor (hereinafter, referred to as an optical sensor) 10 utilizing light reflection is provided so as to face the photosensitive drum 1 surface. Based on the output value of the optical sensor 10, the toner concentration of the developer in the developing unit 4 is determined. That is, the optical sensor 10 is used as a toner density detecting unit in the developing unit 4.

In this embodiment, the cleaning device 7
The collected toner collected in the step is returned to the developing unit 4 and reused. Hereinafter, the reuse of the collected toner will be described. In the transfer process, 100% of the toner image on the surface of the photosensitive drum 1 is not completely transferred, and a part of the toner image remains on the surface of the photosensitive drum 1. The residual toner is scraped off by an elastic rubber blade 7a in the cleaning device 7 rubbing the surface of the photosensitive drum 1. The scraped toner falls into the toner collecting chamber 7b along a toner collecting plate (not shown). Toner collection chamber 7b
A transport roller 7c is provided at the bottom of the. The transport roller 7c is a screw-type rotator rotatably supported on the front and rear side plates of the housing of the cleaning device 7, and rotates the collected toner by a drive mechanism (not shown) to collect the toner. To the collection toner conveying device 8 through the opening.

Here, a collected toner hopper 4f, which is a collected toner storage device, is provided above the developing unit 4 in addition to a toner cartridge 4d, which is a storage device for a supply toner of unused toner (hereinafter, referred to as unused toner). Is provided. The collected toner conveying device 8 is connected to a toner collecting chamber 7b in the cleaning device 7 and a collected toner hopper 4f, which is a collected toner storage device. And a rotating auger 8b. The collected toner is conveyed by the collected toner conveying device 8, collected by the collected toner hopper 4f of the developing unit 4, and is collected by the collected toner replenishing roller 4e, which is a collected toner replenishing device at the bottom of the collected toner hopper 4f. It can be reused by replenishing the appropriate amount in 4. Unused toner in the toner cartridge 4d is utilized by being replenished in an appropriate amount into the developing unit 4 by an unused toner replenishing roller 4c which is an unused toner replenishing device.

The collected toner collected by the cleaning device 7 and conveyed into the collected toner hopper 4f is a toner remaining on the surface of the photosensitive drum 1 at the time of transfer or a toner of the opposite polarity adhering to the non-image portion. Yes, it is electrostatically fatigued due to the history of charging during development and transfer, and its charging polarity is not constant. When such collected toner is reused for development, the amount of triboelectric charge is insufficient at the time of development, or the charging characteristic of the collected toner is often different from the unused toner supplied from the toner cartridge 4d. If the image is reused, the image becomes a dusty image lacking in sharpness.

Therefore, in order to solve the above-mentioned image deterioration, the collected toner in the collected toner hopper 4f is supplied to the developing section 4b of the developing unit 4 after a certain time has passed after being conveyed into the collected toner hopper 4f. By doing so, the charge of the collected toner is attenuated, and the developing unit 4
To prevent a large difference in electrostatic characteristics when mixed with the toner in the developing section 4b. For example, if the copy speed is 1
In the case of the low-speed rotating machine of 5 cpm, from the result of FIG.
When 0 minute has elapsed, that is, when the auger 8b has been stopped for 30 minutes or more, the collected toner is supplied into the developing unit 4b by the collected toner supply roller 4e. As a result, the charge of the collected toner is attenuated so that there is no difference in the electrostatic characteristics between the supplied collected toner and the toner in the developing unit 4b.

However, in the case where the transfer paper is continuously fed, the time required for sufficiently attenuating the charge of the collected toner is not obtained, and an image with many sharpness lacking in sharpness is output. .

Therefore, in the first embodiment, a conveyance control means (not shown) for selectively conveying the collected toner from the cleaning device 7 to the collected toner hopper 4f, and a developing unit from the collected toner hopper 4f by the collected toner supply roller 4e. A supply unit for supplying the collected toner to the developing unit 4b when the conveyance is stopped; and a supply unit for supplying the collected toner to the developing unit 4b. Is stopped, the supply of the collected toner from the cleaning device 7 to the collected toner hopper 4f is stopped, and then the toner is mixed with the toner in the developing unit 4b of the developing unit 4.

According to the copying machine of the first embodiment,
Even in the case where the transfer paper is continuously passed, the charge of the collected toner is sufficiently attenuated in the collected toner hopper 4f, and the difference in the electrostatic characteristics between the supplied collected toner and the toner in the developing unit 4b is reduced. , And the amount of poorly charged toner can be reduced. Therefore, a high-quality image free from background contamination and excellent in sharpness can be obtained, and toner scattering and defective cleaning do not occur.

Next, a second embodiment will be described. FIG.
FIG. 1 is a schematic configuration diagram of a copying machine according to a second embodiment, in which parts similar to those in FIG. 1 showing the schematic configuration of the copying machine according to the first embodiment are denoted by the same reference numerals, Since the functions are the same, the description thereof will be omitted.

By the way, the recovered toner has a poor triboelectric charge rising characteristic as compared with a normal unused toner, and particularly when the temperature is high, the resistance value of the collected toner itself decreases. The difference from the toner becomes remarkable.

Therefore, in the second embodiment, the recovered toner temperature sensor 12 for detecting the temperature of the recovered toner, and the recovered toner replenishing roller 4e for recovering the recovered toner when the temperature of the recovered toner falls below a predetermined temperature. And a not-shown collected toner replenishment control means for replenishing the developing unit 4b. Also, the collected toner hopper 4
f is a ventilation port 13 with a filter for cooling the collected toner.
Is provided. First, after the collected toner collected by the cleaning device 7 is transported to the collected toner hopper 4f by a certain fixed amount, the operation of the auger 8b is stopped, and the supply of the collected toner from the cleaning device 7 to the collected toner hopper 4f is stopped. Then, the temperature of the collected toner is measured by a collected toner temperature sensor 12 attached to the collected toner hopper, and when the temperature of the collected toner falls below a certain set temperature, for example, 30 ° C. or less, the developing unit 4b is operated. Control such as that shown in FIG. 5 is performed by a not-shown collected toner replenishment control unit so as to supply the toner. As shown in FIG. 4, when the temperature of the collected toner becomes 30 ° C. or lower, the halftone uniformity level becomes sufficiently high. Here, FIG.
The data when the temperature inside is 23 ° C.

According to the copying machine of the second embodiment,
Even when the temperature of the collected toner becomes high, the resistance value of the collected toner is reduced, and the rising characteristic of triboelectric charging is deteriorated,
The temperature of the collected toner in the collected toner hopper 4f can be lowered, and there can be no difference in the electrostatic characteristics between the toner in the developing unit 4b of the developing unit 4 and the collected toner. Can be reduced. Therefore, a high-quality image free from background contamination and excellent in sharpness can be obtained, and toner scattering and defective cleaning do not occur.

Next, a third embodiment will be described. FIG.
FIG. 3 is a schematic configuration diagram of a copying machine according to a third embodiment, in which parts similar to those in FIG. Since the functions are the same, the description thereof will be omitted.

In the case where the temperature of the collected toner becomes high and a temperature difference, that is, a resistance value difference between the collected toner and the toner in the developing section 4b of the developing unit 4 is generated, frictional charging of a one-component toner developing device or the like is mainly used. In such a copying machine, the charge amount of the toner in the developing unit 4b changes due to the difference in the temperature of the collected toner, that is, the difference in the resistance value of the toner.

Therefore, in the third embodiment, a collected toner temperature sensor 12 for detecting the temperature of the collected toner, a toner temperature sensor 14 in the developing unit for detecting the temperature of the toner in the developing unit 4b of the developing unit 4, A collection toner replenishment control means (not shown) for replenishing the collected toner into the development section 4b by the collected toner replenishing roller 4e when the temperature of the toner becomes substantially the same as the temperature of the toner in the development section 4b; I have. The recovered toner hopper 4f is provided with a ventilation port 13 with a filter for cooling the recovered toner. First, after the collected toner collected by the cleaning device 7 is conveyed to the collected toner hopper 4f by a certain amount, the operation of the auger 8b is stopped and the cleaning device 7 is stopped.
Then, supply of the collected toner to the collected toner hopper 4f is stopped. Then, the temperature of the collected toner is measured by the collected toner temperature sensor 12 attached to the collected toner hopper, and the temperature of the toner in the developing unit 4b is measured by the toner temperature sensor 14 in the developing unit attached to the developing unit 4b of the developing unit 4. When the temperature of the collected toner and the temperature of the toner in the developing section become substantially the same, for example, when the difference between the two temperatures becomes 10 ° C. or less, replenishment of the collected toner (not shown) is performed. The control as shown in FIG. 8 is performed by the control means. As shown in FIG. 7, when the difference between the temperature of the collected toner and the temperature of the toner in the developing unit is 10 ° C. or less, the halftone uniformity level becomes sufficiently high. Here, FIG.
The data when the temperature inside is 20 ° C.

According to the copying machine of the third embodiment,
The temperature of the collected toner becomes high, and the developing unit 4b of the developing unit 4
In the case where a difference in temperature, that is, a difference in resistance value between the collected toner and the toner in the developing unit 4b occurs,
The charge amount due to frictional charging in the developing unit 4, that is, the charging characteristics can be made the same, and the amount of poorly charged toner can be reduced. Therefore, a high-quality image free from background contamination and excellent in sharpness can be obtained, and toner scattering and defective cleaning do not occur.

Next, a fourth embodiment will be described. FIG.
FIG. 5 is a schematic configuration diagram of a copying machine according to a fourth embodiment, in which parts similar to those in FIG. 1 showing the schematic configuration of the copying machine according to the first embodiment are denoted by the same reference numerals, Since the functions are the same, the description thereof will be omitted.

Most of the collected toner is stressed by the inside of the developing unit 4 or the auger 8b. In an ordinary toner, a hard fine powder typified by silicon oxide, titanium oxide, aluminum oxide, zinc stearate, or the like is mixed with a resin serving as a base for improving fluidity and preventing sticking. I have. However, in the recovered toner subjected to the stress as described above, the additive is often buried in the matrix, and the fluidity and the like are reduced.

Therefore, in the fourth embodiment, before supplying the collected toner into the developing device, the collected toner hopper 4f
As means for mixing the additive into the collected toner inside, an additive tank 15 is provided above the collected toner hopper 4f, and an additive supply roller 15a for replenishing the additive into the collected toner hopper 4f is provided. First, the cleaning device 7
After the collected toner is conveyed to the collected toner hopper 4f by a certain fixed amount, the operation of the auger 8b is stopped, and the supply of the collected toner from the cleaning device 7 to the collected toner hopper 4f is stopped. Then, the additive supply roller 1
After mixing and stirring the additive such as silicon oxide into the collected toner hopper 4f by 5a, the collected toner mixed with the additive is supplied to the developing unit 4b of the developing unit 4.

According to the copying machine of the fourth embodiment,
Even when an additive for improving the fluidity and preventing adhesion is buried in the mother body of the collected toner due to the stress in the developing unit 4 during the development or the stress by the auger 8b, the collected toner and the developing unit 4b And the toner having the same charging characteristics and fluidity as described above, and the amount of poorly charged toner and toner adhesion to the doctor blade 4g and the cleaning blade 7a of the developing unit 4b can be reduced. Therefore, a high-quality image free from background contamination and excellent in sharpness can be obtained, and toner scattering and defective cleaning do not occur.

Next, a fifth embodiment will be described. FIG.
0 is a schematic configuration diagram of a copying machine according to a fifth embodiment,
The same parts as those in FIG. 1 showing the schematic configuration of the copying machine according to the first embodiment are denoted by the same reference numerals, and the functions are the same, so that the description thereof will be omitted.

The recovered toner is the toner remaining on the surface of the photosensitive drum 1 at the time of transfer or the toner attached to the non-image portion and having a polarity opposite to the original charge polarity, and is charged at the time of development or transfer. Has received the history of. Therefore, the collected toner is electrostatically fatigued, and its charging polarity is not constant. When such recovered toner is reused and developed, the charge is insufficient at the time of development,
In many cases, the charging characteristics are different from the unused toner supplied from the toner cartridge 4d.

Therefore, in the fifth embodiment, the collected toner in the collected toner hopper 4f is applied to the developing unit 4b of the developing unit 4.
The auxiliary roller 16 in contact with the collected toner supply roller 4e serves as a collected toner charging unit that is charged to the same polarity as the toner in the toner cartridge.
Is provided. In this embodiment, the collected toner supply roller 4e is a high-resistance sponge roller and is electrically connected to the ground. The auxiliary roller 16 is formed of a low-resistance rubber roller, and a DC power supply 17 applies a DC bias voltage of approximately −100 V having the same polarity as the original charge polarity of the toner. Further, in order to scrape toner from the surface of the collected toner supply roller 4e into the developing section 4b, a scraping member 18 pressed against the collected toner supply roller 4e is also provided. First, the collected toner collected by the cleaning device 7 is collected by the collected toner hopper 4f.
Then, after transporting the toner by a certain amount, the operation of the auger 8b is stopped and the collected toner hopper 4f
Supply of collected toner to the printer is stopped. Then, the collected toner is replenished into the developing unit 4b while being weakly charged to the same polarity as the toner in the developing unit 4b by the collected toner replenishing roller 4e and the auxiliary roller 16 to which the bias voltage is applied.

According to the copying machine of the fifth embodiment,
Even in a case where the collected toner is electrostatically fatigued and the charging polarity is not constant, the deterioration of the rising characteristic of the triboelectric charging of the collected toner is compensated for, and the electrostatic property between the collected toner and the toner in the developing unit 4b is greatly increased. The difference can be prevented, and the amount of poorly charged toner can be reduced. Therefore, a high-quality image free from background contamination and excellent in sharpness can be obtained, and toner scattering and defective cleaning do not occur.

Next, a sixth embodiment will be described. FIG.
FIG. 1 is a schematic configuration diagram of a copying machine according to a sixth embodiment,
The same parts as those in FIG. 10 showing the schematic configuration of the copying machine according to the fifth embodiment are denoted by the same reference numerals, and the functions are the same, so that the description thereof will be omitted.

The difference from the fifth embodiment is that instead of electrically connecting the toner replenishing roller 4e to the ground, an AC power supply 19 supplies the toner replenishing roller 4e with 100 Vp-p,
The point is that an AC bias voltage of 50 Hz and a time average value of 0 V is applied. First, after the collected toner collected by the cleaning device 7 is transported to the collected toner hopper 4f by a certain fixed amount, the operation of the auger 8b is stopped, and the supply of the collected toner from the cleaning device 7 to the collected toner hopper 4f is stopped. Then, the charge of the collected toner is eliminated by the collected toner supply roller 4e to which the AC bias is applied and the auxiliary roller 16 to which a DC bias voltage of about -100 V is applied, and the collected toner is made the same as the toner in the developing section 4b. The developer is replenished into the developing unit 4b while being weakly charged.

According to the copying machine of the sixth embodiment,
Even in a case where the collected toner is electrostatically fatigued and the charging polarity is not constant, the deterioration of the rising characteristic of the triboelectric charging of the collected toner is compensated for, and the electrostatic property between the collected toner and the toner in the developing unit 4b is greatly increased. The difference can be prevented, and the amount of poorly charged toner can be reduced. Therefore, a high-quality image free from background contamination and excellent in sharpness can be obtained, and toner scattering and defective cleaning do not occur. In the sixth embodiment, the application of the DC voltage to the auxiliary roller 16 is not necessarily performed.

Next, a seventh embodiment will be described. FIG.
FIG. 2 is a schematic configuration diagram of a copying machine according to a seventh embodiment,
The same parts as those in FIG. 1 showing the schematic configuration of the copying machine according to the first embodiment are denoted by the same reference numerals, and the functions are the same, so that the description thereof will be omitted.

As described above, since the collected toner has a lower fluidity than ordinary unused toner, the collected toner is transferred to the auger 8 in the thin conveying pipe 8a.
In the case where the sheet is conveyed in b, a problem may occur that the collected toner adheres to the auger 8b. Further, this fixation may cause damage to a gear for rotating the auger 8b. Even if the gear is not damaged, the collected toner fixed to the auger 8b cannot be reused.

Therefore, in the seventh embodiment, as means for cooling the collected toner conveying device 8, the duct 20 is provided around the conveying pipe 8a and the auger 8b, and the air in the duct 20 is exhausted to one end of the duct 20. Exhaust fan 21 is provided.

According to the copying machine of the seventh embodiment,
By lowering the temperature of the transport pipe 8a and the auger 8b, the fixation of the collected toner to the transport pipe 8a and the auger 8b and the aggregation of the collected toner can be prevented. Therefore, a high-quality image with excellent sharpness without background contamination can be obtained without causing a mechanical trouble of the collected toner conveying device 8 at the time of conveying the collected toner,
No cleaning failure occurs.

Further, according to the copying machine of the above embodiment, the collected toner can be reused effectively, and the collected toner does not need to be discarded. It can also contribute to environmental conservation and reduction of industrial waste.

The above-described first to seventh embodiments may be appropriately combined with each other, in which case a greater effect can be obtained.

[0054]

According to the first aspect of the present invention, even in the case where the transfer paper is continuously fed, the charge of the opposite polarity of the collected toner is sufficiently attenuated in the collected toner storage device. It is possible to prevent the difference in electrostatic characteristics between the replenished collected toner and the toner in the developing device, and reduce the amount of poorly charged toner. There is an excellent effect that a quality image can be obtained and that toner scattering and cleaning failure do not occur.

According to the second aspect of the present invention, even when the temperature of the collected toner becomes high, the resistance value of the collected toner is reduced, and the rising characteristic of triboelectric charging is deteriorated, the collected toner is stored. The temperature of the collected toner in the apparatus can be lowered, the difference in electrostatic characteristics between the toner in the developing device and the collected toner can be prevented, and the amount of poorly charged toner can be reduced. So you can
An excellent effect that a high quality image excellent in sharpness without background contamination is obtained, and toner scattering and poor cleaning do not occur.

According to the third aspect of the present invention, even when the temperature of the collected toner becomes high and a difference in temperature, that is, a difference in resistance between the collected toner and the toner in the developing device occurs, the collected toner and the collected toner are removed. Since the amount of charge, that is, the charging characteristics of the toner in the developing device due to frictional charging in the developing device can be made the same, and the amount of poorly charged toner can be reduced, the sharpness without background contamination can be reduced. An excellent effect is obtained that a high-quality image with excellent properties is obtained, and that toner scattering and poor cleaning do not occur.

According to the fourth aspect of the present invention, an additive for improving fluidity and preventing sticking is formed in the base of the recovered toner due to stress or the like in the developing device and the recovered toner conveying device. Even when the toner is buried in the developing device, the collected toner and the toner in the developing device can have the same charging characteristics and fluidity, so that the poorly charged toner and the toner adhesion to the doctor blade and the cleaning blade can be reduced. Therefore, a high quality image having excellent sharpness without background contamination can be obtained, and there is an excellent effect that toner scattering and cleaning failure do not occur.

According to the fifth aspect of the present invention, even when the collected toner is electrostatically fatigued and the charging polarity is not constant, the deterioration of the rising characteristic of the triboelectric charging of the collected toner is compensated for. It is possible to prevent a large difference in electrostatic characteristics between the collected toner and the toner in the developing device and to reduce the amount of poorly charged toner. An excellent effect is obtained, and toner scattering and poor cleaning do not occur.

According to the sixth aspect of the present invention, even when the collected toner is electrostatically fatigued and the charging polarity is not constant, the deterioration of the rising characteristic of the triboelectric charging of the collected toner is compensated for. It is possible to prevent a large difference in electrostatic characteristics between the collected toner and the toner in the developing device, and to reduce the amount of poorly charged toner. Is obtained, and
There is an excellent effect that toner scattering and cleaning failure do not occur.

According to the seventh aspect of the invention, the temperature of the collected toner conveying device can be lowered to prevent the collected toner from sticking to the collected toner conveying device and the aggregation of the collected toner. When the collected toner is transported, a high-quality image with excellent sharpness without background contamination can be obtained without causing a mechanical trouble of the collected toner transporting device, and toner scattering and cleaning failure can be prevented. There is an excellent effect that it does not occur.

Further, according to the first to seventh aspects of the present invention, the collected toner can be reused effectively and the collected toner does not need to be discarded. There is an excellent effect that it can contribute to resource protection, environmental protection and reduction of industrial waste.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a copying machine according to a first embodiment.

FIG. 2 is a characteristic diagram illustrating a relationship between a stop time of the collected toner conveying device and a halftone uniformity level of an image.

FIG. 3 is a schematic configuration diagram of a copying machine according to a second embodiment.

FIG. 4 is a characteristic diagram showing a relationship between a collected toner temperature and a halftone uniformity level of an image.

FIG. 5 is a flowchart illustrating control of supplying collected toner according to a second embodiment.

FIG. 6 is a schematic configuration diagram of a copying machine according to a third embodiment.

FIG. 7 is a characteristic diagram showing a relationship between a difference between a collected toner temperature and a toner temperature in a developing unit and a halftone uniformity level of an image.

FIG. 8 is a flowchart of control of supplying collected toner according to a third embodiment.

FIG. 9 is a schematic configuration diagram of a copying machine according to a fourth embodiment.

FIG. 10 is a schematic configuration diagram of a copying machine according to a fifth embodiment.

FIG. 11 is a schematic configuration diagram of a copying machine according to a sixth embodiment.

FIG. 12 is a schematic configuration diagram of a copying machine according to a seventh embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 photoconductor drum 4 developing unit 4b developing unit 4e collected toner supply roller 4f collected toner hopper 8a transport pipe 8b auger 12 collected toner temperature sensor 14 toner temperature sensor in developing unit 15 additive tank 16 auxiliary roller 20 duct 21 exhaust fan

────────────────────────────────────────────────── ─── Continuation of the front page (72) Mayumi Yoshida, Inventor Ricoh Company, Ltd. 1-3-6 Nakamagome, Ota-ku, Tokyo (56) References JP-A-62-111680 (JP, A) JP-A Sho 55-149966 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/10-21/12 G03G 15/08-15/08 507 G03G 15/00 303 G03G 21/00 370-540 G03G 21/14

Claims (7)

(57) [Claims] A cleaning device for removing residual toner after transfer on the surface of the image bearing member; a collected toner storage device provided separately from an unused toner storage device in a developing device; and a collected toner removed by the cleaning device. And a collected toner supply device that supplies the collected toner from the collected toner storage device to the developing device, and a collected toner supply device that supplies the collected toner from the unused toner storage device to the developing device. An image forming apparatus having an unused toner replenishing device for replenishing unused toner, a conveyance control unit for selectively conveying the cleaning device to the collected toner storage device, and An image forming apparatus comprising: a supply unit configured to supply the collected toner into the apparatus when the conveyance is stopped. 2. A cleaning device for removing residual toner after transfer on the surface of an image carrier, a collected toner storage device provided separately from an unused toner storage device in a developing device, and a collected toner removed by the cleaning device. And a collected toner supply device that supplies the collected toner from the collected toner storage device to the developing device, and a collected toner supply device that supplies the collected toner from the unused toner storage device to the developing device. An image forming apparatus having an unused toner replenishing device for replenishing unused toner, wherein a means for detecting a temperature of the collected toner, and a method for detecting the temperature of the collected toner when the temperature of the collected toner falls below a predetermined temperature. An image forming apparatus comprising: a collected toner replenishment control unit for replenishing collected toner into the developing device. 3. A cleaning device for removing residual toner after transfer on the surface of an image carrier, a collected toner storage device provided separately from an unused toner storage device in a developing device, and a recovered toner removed by the cleaning device. And a collected toner supply device that supplies the collected toner from the collected toner storage device to the developing device, and a collected toner supply device that supplies the collected toner from the unused toner storage device to the developing device. In an image forming apparatus including an unused toner replenishing device for replenishing unused toner, a unit for detecting a temperature of the collected toner, a unit for detecting a temperature of the toner in the developing device, and a temperature of the collected toner Is substantially the same as the temperature of the toner in the developing device,
An image forming apparatus provided with a collected toner replenishment control unit for replenishing the collected toner into the developing device. 4. A cleaning device for removing residual toner after transfer on the surface of an image carrier, a collected toner storage device provided separately from an unused toner storage device in a developing device, and a recovered toner removed by the cleaning device. And a collected toner supply device that supplies the collected toner from the collected toner storage device to the developing device, and a collected toner supply device that supplies the collected toner from the unused toner storage device to the developing device. In an image forming apparatus having an unused toner replenishing device for replenishing unused toner, an additive is added to the collected toner in the collected toner storage device before replenishing the collected toner into the developing device. An image forming apparatus comprising a mixing unit. 5. A cleaning device for removing residual toner after transfer on the surface of an image carrier, a collected toner storage device provided separately from an unused toner storage device in a developing device, and a recovered toner removed by the cleaning device. And a tray for replenishing the collected toner from the collected toner storage device into the developing device .
A toner supply device having a toner supply roller, and an unused toner supply device for supplying unused toner from the unused toner storage device to the developing device. and recovering the toner charging means for charging the toner of the same polarity as the developing apparatus the collected toner
An auxiliary roller in contact with the toner supply roller;
DC bias voltage of the same polarity as the charging polarity of the toner in the device
And a DC power supply for applying a voltage to the auxiliary roller . 6. A cleaning device for removing residual toner after transfer on an image carrier surface, a collected toner storage device provided separately from an unused toner storage device in a developing device, and a recovered toner removed by the cleaning device. And a collected toner supply device that supplies the collected toner from the collected toner storage device to the developing device, and a collected toner supply device that supplies the collected toner from the unused toner storage device to the developing device. An image forming apparatus comprising: an unused toner replenishing device for replenishing unused toner; and an apparatus for applying an AC voltage to the collected toner in the collected toner storage device. 7. An image forming apparatus according to claim 1, further comprising means for cooling said collected toner conveying device.