JPH07120130B2 - Copier cleaning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for removing a developer remaining on a photoconductor of a copying material, and particularly to an electrostatic attraction force using a brush in which conductive fibers are implanted. The present invention relates to a cleaning device for a copying machine, which cleans a photoconductor by using the.

2. Description of the Related Art Generally, a cleaning pretreatment step, a cleaning step, and a dust collecting step are required to remove the untransferred toner remaining on the photoconductor of a copying machine.

The cleaning pretreatment step is performed in order to fully bring out the capability of the cleaning device in the cleaning step, and a method of controlling the charges of the toner and the photoconductor is usually adopted.

As one of the methods, in order to electrically neutralize both the toner and the photoreceptor to weaken the binding force between them, corona irradiation with a clean corotron or light irradiation with a pre-clean lamp is used. ing.

As another method, in order to give an optimum electric charge to the toner, a method is known in which the toner is removed by an electrostatic action after irradiating the corona with a preclean corotron.

On the other hand, as a cleaning method used in the cleaning step, a method using a magnetic cleaning means such as a magnetic brush cleaning and a magnetic roll cleaning, and a method using a mechanical cleaning means such as a fur brush cleaning and a blade cleaning are known. . The one using the magnetic cleaning means is characterized in that it has a small mechanical impact on the photoconductor, is small and inexpensive, and has low noise. It has drawbacks such as being greatly affected by its characteristics and being susceptible to environmental conditions for its cleaning ability.

Further, among the mechanical cleaning means, a fur brush cleaning device using a fur brush has features such as stable cleaning performance and compatibility with a high-speed copying machine, but has a drawback that noise due to a fan is large. is there.

Furthermore, a blade cleaning device using a cleaning blade is designed to scrape off the toner adhering to the surface of the photoconductor with the edge of a rubber blade such as polyurethane rubber, and has features such as low cost, low noise, and small space. However, it has the disadvantage that good contact between the blade edge and the photoreceptor must be maintained.

On the other hand, the dust collecting step becomes a problem especially in a brush cleaning device, and a filter bag, a cyclone filter, a skiaving roll, etc. are generally used as a mechanism and a device for separating the toner mixed with air and discharged.

In addition to the above-mentioned cleaning method, when an electrostatic field is generated between the photoconductor surface and a cleaning member such as a fiber brush or a magnetic brush, the suction of the toner to the cleaning brush surface may be strengthened. It is disclosed in US Pat. No. 3722018.

Further, in order to generate an electrostatic field necessary for removing the toner between the conductive brush and the photoconductor and between the collecting rolls,
A device to which a bias voltage is applied is disclosed in, for example, JP-A-57-100460.
No. etc. are known.

As shown in FIG. 6, the basic configuration of the cleaning device so far is such that a conductive brush b is provided so as to be in sliding contact with the photosensitive member a, and a recovery roll c is provided so as to be in contact with the conductive brush b. At the same time, a bias power supply h is applied to the conductive brush b, and a bias power supply i having a polarity higher than the bias voltage i is applied to the recovery roll c.

The conductive brush b and the recovery roll c are housed in a grounded housing d so that they can be rotated in the direction of the arrow by a drive system (not shown), and a pre-cleaning roller is provided in front of the housing d. A tron e and a lamp e'are installed.

In the cleaning device configured as described above, the untransferred toner remaining on the photoconductor a after the transfer process is first charged to a single polarity, for example (-), by the precleaning corotron e to which the direct current power source j is applied, and then is electrically conductive. Reach sex brush b. A bias voltage of reverse polarity is applied to the conductive brush b so as to electrostatically adsorb and remove the residual toner on the photosensitive member a when slidingly contacting the photosensitive member a. The attracted toner is transferred to the collecting roll c and then scraper f is provided so as to contact the collecting roll c.
It is scraped off by and is carried out of the housing d by a carrying device g such as a screw conveyor.

Problems to be Solved by the Invention However, the above cleaning device has the following problems.

(1) Due to the pre-cleaning corotron e, all the toner may not be uniformly charged to the same polarity, and the toner that is not adsorbed on the conductive brush b is scattered by the rotation of the conductive brush b and the inside of the copying machine is scattered. To be polluted.

(2) Since the housing d is made of metal such as aluminum and is grounded for safety, an electrostatic field is generated between the housing d and the conductive brush b. Toner having the same polarity as that of the conductive brush b is scattered in the direction of the housing d by the electrostatic and mechanical force due to the splashing and adheres and deposits on the inner surface of the housing d. There is a problem that the image quality of the copied image is deteriorated.

The present invention has been made for the purpose of improving the above problems.

Means and Actions for Solving Problems In order to achieve the above object, the present invention applies untransferred toner remaining on the surface of an endless belt-shaped photosensitive member after a transfer process to a bias voltage having a polarity opposite to that of the toner. In a cleaning device of a copying machine in which the above-mentioned electroconductive brush is rotated and slidably contacted with the photoconductor to electrostatically adsorb and remove it, the electroconductive brush is arranged above the photoconductor, and the electroconductive brush is housed to expose the photoconductor. With a housing that opens downward toward the body,
Between the conductive brush and the housing, there is formed a space in which toner in the untransferred toner and having the same polarity as the conductive brush is scattered by the rotation of the conductive brush, and the same polarity as the conductive brush is formed in the housing. By applying a bias voltage of the same potential, the electrostatic field is prevented from being generated between the conductive brush and the housing. As a result, the conductivity of the untransferred toner scattered by the rotation of the conductive brush is prevented. It is possible to reduce the adhesion of the toner having the same polarity as that of the brush to the inner surface of the housing, and to prevent the accumulated toner from agglomerating and dropping onto the photoconductor.

Embodiment An embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 2 is an overall view of an electronic copying machine in which the present invention can be suitably implemented, in which 1 is a tension. An endless belt-shaped photoconductor wound around the roll 2, the peeling roll 3, and the drive roll 4, and is adapted to be rotated by the drive roll 4 in the arrow direction.

In the vicinity of the photoconductor 1, reflected light from the charger 5 for charging the photoconductor 1 and the original 7 to be copied placed on the original table 6 is imaged on the surface of the photosensitive body 1. An optical system 8 for forming an electrostatic latent image, a developing device 9 for developing the electrostatic latent image formed on the surface of the photoconductor 1 into a visible image (toner image), and a paper feeding device 10.
A transfer device 12 that transfers the visible light on the surface of the photoconductor 1 to the paper 11 that has been fed, a fixing device 30 that permanently fixes the toner transferred to the paper 11 after the transfer process, and a paper that progresses after fixing.
A shout 32 for guiding 11 to the cache tray 31, and a pre-clean lamp 13 'for uniformly discharging the surface of the photoconductor 1.
And a pre-clean corotron 13 that charges untransferred toner to a uniform polarity, and a photoreceptor 1 after a cleaning pretreatment process
A cleaning device main body 14 for removing the untransferred toner remaining on the surface of the photoconductor 1 is installed in the above order along the rotation direction of the photoconductor 1.

On the other hand, the cleaning device main body 14 has two electrically insulated housings 15 and 16 as shown in FIG. One of the housings 15 and 16 is installed so as to be closer to the photoconductor 1 from above, and the lower side, which is a surface facing the photoconductor 1, is opened, and is disposed above the photoconductor 1 inside. Then, the conductive brush 17 is housed so that the tip of the brush contacts the surface of the photoconductor 1. By thus positioning the cleaning device 14 above the photoconductor 1,
The heavy developing device 9 can be located below the photoconductor 1. The conductive brush 17 has a cylindrical core.
A large number of conductive fibers 17b are planted on the surface of 17a, which is rotated by a drive system (not shown) in the direction of the arrow to remove the untransferred toner remaining on the surface of the photosensitive member 1. A bias voltage of, for example, +200 V is applied to the conductive brush 17 and the housing 15 from a DC bias power source 18. In addition, the toner in the untransferred toner between the conductive brush 17 and the housing 15 is a conductive brush.
The toner having the same polarity as that of 17 forms a space in which the conductive brush 17 is rotated to scatter. On the other hand, an opening 15a that opens into the housing 16 is provided in the upper part of the housing 15, and a recovery roll 19 is provided in the opening 15a so as to be in contact with the conductive brush 17.

The collecting roll 19 is rotated in the direction of the arrow by a drive system (not shown), and a bias voltage of, for example, + 500V is applied by the toner collecting bias power source 20 in the same manner as the conductive brush 17, and the surface of the photoconductor 1 is covered. The toner attracted by the conductive brush 17 is further attracted and removed by the conductive brush 17.

Then, the toner adsorbed on the collecting roll 19 is scraped off by a scraper 21 made of a metal such as a stainless plate provided so as to be in contact with the collecting roll 19, and then transferred from inside the housing 16 by a conveying means 22 such as a screw conveyor. The housing 16 is designed so that it can be carried out.
Is grounded to one side of the DC bias power supply 18.

The cleaning device main body 14 having the above-described structure is configured such that the toner image is transferred onto the paper 11 by a normal copying process, and then the photoreceptor 1
The untransferred toner remaining on the surface of is removed in the following manner.

That is, the untransferred toner remaining on the surface of the photoreceptor 1 after the transfer step is uniformly charged by the preclean corotron 13, and at the same time, the photoreceptor 1 is illuminated by the preclean lamp 13 'from the transparent support side of the photoreceptor 1. After the binding force with the surface of the cleaning device is weakened, it reaches the conductive brush 17 provided in the cleaning device main body 14. A bias voltage having a polarity opposite to that of the toner is applied to the conductive brush 17 and the housing 15 containing the conductive brush 17 by a DC bias power source 18, and the residual toner is removed by the conductive brush 17 which rotates while slidingly contacting the surface of the photoconductor 1. Since it is removed from the surface of the photoconductor 1 and the bias voltage having the same electric potential as that of the conductive brush is applied to the housing 15 at this time, no electrostatic field is generated between the two and the untransferred. Toner that is not charged to the same polarity by the preclean corotron 13 in the toner, that is, even if toner of the same polarity as the conductive brush 17 is scattered by the rotation of the conductive brush 17, the space is scattered and the inner surface of the housing 15 is scattered. It becomes difficult to adhere to the inner surface of the housing 15, and the amount of adhesion and deposition on the inner surface of the housing 15 can be reduced.

The toner adsorbed on the conductive brush 17 is collected by the recovery roll 19
After being transferred to the housing 16, it is scraped off from the surface of the recovery roll 19 by the scraper 21 and further transferred to the housing 16 by the conveying means 22.
It is carried out from the inside and collected.

In the above embodiment, the outer surface of the housing 15 may be covered with an insulator in order to enhance safety.

On the other hand, FIG. 3 shows an example in which a bias voltage is applied to the scraper 21 for scraping off the toner from the recovery roll 19 as in the case of the recovery roll 19. The scraper 21 is made of metal such as stainless steel plate. As described above, the scraper 21 is supported by a hopper 24 made of an insulating material provided below the conveying means 22,
It is electrically insulated.

Therefore, static electricity generated by frictional contact with the recovery roll 19 is likely to accumulate.

On the other hand, the surface of the recovery roll 19 has a thin insulating layer 19 such as alumite.
The insulating layer 19a is covered with a, and there is a thin portion of the insulating layer 19a with a pinhole or the like generated at the time of manufacturing, and spark discharge may occur due to the electric charge charged to the scraper 21 through this portion. .

As a result, while the insulating layer 19a is destroyed and the insulating layer 19a is small, the current is limited by the resistance component of the conductive fibers 17b even if the conductive brush 17 is in contact with the conductive brush 17 and the recovery roll.
Spark discharge does not occur between 19, but when the breakdown becomes large, spark discharge occurs and the potential difference between the two becomes smaller than the set value. As a result, the recovery rate of the toner attached to the conductive brush 17 decreases, the toner accumulates on the conductive brush 17, and the cleaning effect decreases.

Therefore, in the above-described embodiment, a bias voltage is applied to the scraper 21 in the same manner as the recovery roll 19 so that the scraper 21 and the scraper 21 have the same potential.

As a result, even if there is a pinhole or the like in the insulating layer 19a of the recovery roll 19, no spark discharge is generated between the recovery roll 19 and the scraper 21, so that the insulation layer 19a can be prevented from being destroyed.

In addition, FIG. 4 shows that the recovery roll 19 is provided with a high resistance (5 to 50 MΩ) 25 for limiting the current in the bias applying circuit.
Even if the insulating layer 19a of 9 has a thin portion due to a pinhole or the like and is electrostatically destroyed, by limiting a large current flowing into the collecting roll 19, a spark discharge is generated between the collecting roll 19 and the scraper 21. It is something that has not happened.

As a result, the insulating layer 19a of the recovery roll 19 is not largely destroyed, and therefore it is possible to prevent the cleaning effect from being lowered due to the same reason as in the above embodiment.

Further, FIG. 5 shows an embodiment in which the bias voltage applied to the recovery roll 19 is applied to the scraper 21 through the high resistance (5 to 50 MΩ) 26 for current limiting.
The electric charge charged on the scraper 21 is gradually discharged to the recovery roll 19 side through the high resistance 26, so that a high voltage that causes a spark discharge is not accumulated in the scraper 21. For the same reason, it becomes possible to prevent a large breakage of the insulating layer 19a and a reduction in the cleaning effect.

EFFECTS OF THE INVENTION As described in detail above, according to the present invention, the conductive brush is disposed above the photoconductor, and the conductive brush is housed and the housing is opened downward toward the photoconductor. A space is formed between the brush and the housing, in which toner in the untransferred toner and having the same polarity as the conductive brush is scattered by the rotation of the conductive brush, and the housing has the same polarity and the same polarity as the conductive brush. Since the bias voltage of the electric potential is applied, the good layout in the copying machine in which the cleaning device can be located above the photoconductor and the heavy developing device can be located below the photoconductor can be achieved. , The electrostatic field is not generated between the conductive brush and the housing, which is the toner in the untransferred toner scattered by the rotation of the conductive brush and is the same as the conductive brush. It is possible to reduce the amount of the polar toner that adheres and accumulates on the inner surface of the housing, and it is possible to prevent the accumulated toner from dropping onto the photoconductor and degrading the image quality.

[Brief description of drawings]

The drawings show one embodiment of the present invention, FIG. 1 is an enlarged sectional view of this apparatus, FIG. 2 is an overall configuration diagram, and FIGS. 3 to 5 are explanatory views showing other embodiments. FIG. 6 is a conventional explanatory view. 1 is a photoconductor, 15 is a housing, and 17 is a conductive brush.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiro Iwaoka 2274 Hongo, Ebina City, Kanagawa Fuji Zero Tsuxu Co., Ltd. Ebina Works (56) References JP-A-58-1176 (JP, A) JP-A-57- 100460 (JP, A)

Claims (1)

[Claims] 1. A non-transferred toner remaining on the surface of an endless belt-shaped photoconductor 1 after a transfer process is brought into sliding contact with a conductive brush 17 to which a bias voltage having a polarity opposite to that of the toner is applied. In a cleaning device for a transfer machine, which electrostatically adsorbs and removes electrostatically, a housing in which the conductive brush 17 is disposed above the photoconductor 1, the conductive brush 17 is housed, and the photoconductor 1 is opened downward. Along with 15, the space between the conductive brush 17 and the housing 15 is formed in which toner in the untransferred toner and having the same polarity as the conductive brush 17 is scattered by the rotation of the conductive brush 17, A cleaning device for a copying machine, wherein a bias voltage having the same polarity and the same potential as that of the conductive brush 17 is applied to the housing 15.