JPS58143366A - Cleaning device - Google Patents

Abstract

PURPOSE:To elongate the life and reduce the quantity of consumption of the magnetic carrier, and also to improve the toner collecting efficiency, by constituting a titled device of a magnetic brush provided so as to slide-rub the surface of an image carrying body, a means for supplying the magnetic carrier to the circumferential surface of its cylindrical body, and its collecting means. CONSTITUTION:A cleaning device is stored and installed as a whole in a housing 12, and on the upstream side in the rotating direction of a photosensitive drum 20, a fur brush 9 is provided, and on its downstream side, a magnetic brush 1 is provided. The fur brush 9 is provided so as to be rotatable, so that the brush fur plated on its circumferential surface, slide-rubs the circumferential surface of the drum 20 at a higher speed than its peripheral speed, in the direction opposite to its running direction. Also, in the lower end part of the housing 12, a discharge screw 10 for removing a toner is provided on a position to which a toner hits out and drops from the inside of the brush fur of the fur brush 9 by flickers 9a, 9b. In this way, the cleaning efficiency is further improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device for removing untransferred toner remaining on the surface of an image carrier of an electrophotographic copying machine, and particularly to a cleaning device for removing untransferred toner remaining on the surface of an image carrier of an electrophotographic copying machine. This paper proposes a cleaning device that saves money and efficiently recovers toner from a carrier.

In an electrophotographic camera, an electrostatic latent image corresponding to the original image is formed on the surface of a photoreceptor, which is an image carrier, and then it is made visible by toner development steps 1 and 2, and this latent image is transferred to a transfer material. However, untransferred toner remaining on the surface of the photoreceptor without being transferred to the transfer material is removed by a cleaning device.

FIG. 2 is a schematic diagram of a conventional magnetic plastic IJ-ning device.3 The photoreceptor drum 20 rotates at a constant speed in the direction of the arrow.
The magnetic plan 21 disposed near the photoreceptor drum 20 has a magnet 22 built into the cylindrical body, and the magnetic carrier attached to the circumferential surface of the cylinder rubs the circumferential surface of the photoreceptor drum 20. It is rotatable in the direction of the arrow. A bias roller 23 is rotatably provided in the direction of the arrow at the position where the magnetic brush 21 rubs, and a blade 24 is provided so as to rub against the circumferential surface of the roller 23.

A magnetic carrier (not shown) such as iron powder is attached to the circumferential surface of the cylindrical body of the magnetic brush 21 by the magnetic force of the magnet 22, and untransferred toner on the circumferential surface of the photosensitive drum 20 is magnetically attached. Due to the sliding of the brush 21, it adheres to the circumferential surface of the carrier which is frictionally charged, and reaches the location of the roller 23 together with the carrier. The toner on the circumferential surface of the carrier is then transferred to a roller 2 to which a bias voltage having a polarity opposite to that of the toner is applied.
The toner transferred to the circumferential surface of 3 and attached to this circumferential surface is scraped off by the blade 24.

However, conventionally, the toner adhering to the circumferential surface of the carrier is not removed, so toner accumulates on the circumferential surface of the carrier in a short period of time, and the carrier loses its ability to attach new toner, resulting in a short carrier life. There was an inconvenience.

Further, due to the accumulation of toner, the triboelectric charging ability of the carrier is reduced, resulting in poor cleaning efficiency and low toner recovery efficiency. Furthermore, the carrier is roller 2
3. Therefore, there is an inconvenience that a large amount of carrier is mixed into the collected toner, resulting in problems such as increased consumption of carrier, inability to reuse the collected toner, and unstable cleaning performance. was pointed out.

In addition to the above-mentioned cleaning device that uses a magnetic brush, there are cleaning devices that use a blade, web, or ij fur brush to clean the surface of the photoreceptor. 1 is in sliding contact, the surface of the photoreceptor will be damaged for a long time, and fur brush cleaning/cleaning tends to cause so-called toner filming, where a thin film of toner remains on the surface of the photoreceptor after it passes through the cleaning device. Therefore, this is not preferable in terms of preventing a reduction in the life of the photoreceptor.

The present invention has been made in view of the above points, and is a cleaning device that aims to extend the lifespan and reduce consumption of carriers in magnetic brush cleaning, and improve cleaning performance by improving toner recovery efficiency. The purpose is to provide A cleaning device according to the present invention is a cleaning device that removes untransferred toner remaining on the surface of an image carrier, in which a magnet is built inside a cylinder, and a magnetic carrier is attached to the circumferential surface of the cylinder to clean the surface of the image carrier. a magnetic brush that is rotatably provided so as to rub; a supply means that supplies a magnetic carrier to the circumferential surface of the mJ cylinder of the magnetic brush; and a supply means that supplies the magnetic carrier from the circumferential surface of the cylinder.
The present invention is characterized in that it has a collecting means for collecting. In this case, the magnetic carrier collected by the collecting means is configured to be fed to the supplying means [7], the magnetic carrier is circulated within the apparatus, and the magnetic carrier is By arranging a roller facing the feeding path and to which a bias voltage having a polarity opposite to the charged polarity of the toner is applied, the toner that has stuck to the circumferential surface of the magnetic carrier is brought to the surface of the roller. It can be transferred and collected. - Further, by providing an electrode to face the roller via the feeding path and grounding the electrode or applying a voltage lower than the bias voltage of the roller, toner collection by the roller can be efficiently performed. can be made into a target. The supply means collects the magnetic carrier collected by the collection means and passes through the o-ra arrangement position, and the toner removed from the surface of the image carrier by the rubbing of the magnetic brush. It is preferable that the mixture is stirred and mixed and then supplied to the circumferential surface of the cylinder of the magnetic brush. In a second cleaning device according to the present invention, a fur brush is rotatably provided upstream of the magnetic brush so as to rub the surface of the image carrier. In this case, a wiper blade that slides on the peripheral surface of the roller and a flicker whose tip is positioned between the bristles of the fur brush are provided, and the peripheral surface of the roller scraped by the wiper blade is It is preferable to collect the toner by providing a discharge screw that collects the toner and the toner between the brush bristles that has been knocked out by the flicker and removes them together.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing one embodiment of the present invention. The photoreceptor drum 20 (in the figure, only the aspect near the cleaning device according to the present invention is shown) has on its circumferential surface,
A photoreceptor is formed of a photosensitive layer on the front side and a conductor layer on the inner side, and is driven to rotate at a constant speed in the direction of the arrow.

The photosensitive layer is made of a photoconductive material such as amorphous selenium or selenium thread alloy, and the conductive layer is grounded.

Near the circumferential surface of the photosensitive drum 20, a charging device 11, an image exposure device, a developing device, a transfer device, and, if necessary, a static eliminating device (all not shown) are arranged in this order in the rotation direction. A cleaning device according to the present invention that destroys the magnetic brush 1 and the fur brush 9' is disposed between the static eliminator (or transfer device) and the charging device. [2] Then, the photosensitive layer of the photosensitive drum 20 is uniformly charged to a positive polarity by a charging device, the document image is exposed to light by an image exposure device to form an electrostatic latent image, and then an electrostatic latent image is formed. A toner image is formed by supplying toner charged to a negative polarity, for example, a polarity opposite to the uniform charging polarity, by a developing device. This i-Boo image is transferred onto a transfer material by a transfer device, and the transferred image is subjected to a fixing process in a subsequent process. Therefore, the untransferred toner remaining on the circumferential surface of the photoreceptor drum 20 without being transferred to the transfer material by the transfer device is either one or the toner has a polarity opposite to the charged polarity of the toner, for example, a positive polarity. The cleaning device according to the present invention is installed after the static electricity is removed by a static eliminator connected to a high-voltage power source to reduce the amount of charge and weaken the electrostatic adhesion to the circumferential surface of the photoreceptor drum 20. reach the position.

The cleaning device is entirely housed in a housing 12), and a fur brush 9 is disposed on the upstream side in the rotational direction of the photosensitive drum 20, and a magnetic brush 1 is disposed on the downstream side. The fur brush 9 is rotatably provided so that the bristles planted on the fur brush 9 rub the circumferential surface of the photoreceptor drum 20 in a direction opposite to its traveling direction at a speed equal to or higher than its circumferential speed. It is preferable to use conductive fibers for the brush bristles, and the bristles are grounded to reduce the electrostatic adhesion force between the photoreceptor surface and the toner, or, if necessary, to reduce the electrostatic adhesion force between the photoconductor surface and the toner, or if necessary, to make the brush bristles have a polarity different from that of the toner. By applying a bias voltage of 1 to the brush bristles, the cleaning efficiency of the fur brush 9 can be improved. Furthermore, rayon or blended fibers may be used as the brush bristles. The fur brush 9 is surrounded by a housing 12 and a partition plate 13 that partitions the fur brush 9 and the magnetic brush 1, and the housing 12 and the partition plate 13 each have a flicker 9a.
+9b is provided with its tip protruding into the bristles of the fur brush 9. At the lower end of the housing 12, the flickers 9a and 9b are provided with a sciffer brush 9.
A discharge screw 10 for removing toner is provided at a position where the toner knocked out from inside the brush bristles falls.

The cylinder body 2 of the magnetic brush 1 has its longitudinal direction aligned with the photosensitive drum 2.
It is provided near the circumferential surface of the photoreceptor drum 20 so as to rotate in the direction opposite to the moving force direction of the circumferential surface, and the cylinder body 2 has a polarity opposite to the charged polarity of the toner. Bias voltage is applied. A plurality of magnets 3 are installed inside the cylinder 2 either fixedly or rotatably together with the cylinder 2, and the lines of magnetic force formed near the circumferential surface of the cylinder 2 by the magnets 3 cause the cylinder 2 to A magnetic carrier such as iron powder is stuck in a brush shape on the outer peripheral surface of the holder. This carrier is attached to the outer circumferential surface of the cylinder 2 by the magnetic force of the magnet 3 and is rotated on the circumferential surface of the photoreceptor drum 20 (7) to separate the toner sticking to the circumferential surface by rubbing the circumferential surface. and attach it to the circumferential surface of the carrier.
Toner is removed from the circumferential surface of the photosensitive drum 20. On the downstream side of the photoconductor param 20 in the rotating direction of the magnetic brush 1, a paddle 8 is provided rotatably in the direction of the arrow. The paddle 8 has a magnetic brush l in its axial direction.
It has a plurality of flat blades extending in the axial direction. Among the magnets 3 inside the cylindrical body 2 in which the magnetic brush 1 is formed, the magnets 3a and 3b adjacent to the paddle 8 are configured to have the same polarity. Therefore, the carriers on the cylindrical body 2 fall from the cylindrical body 2 due to the force of the repulsive magnetic field of the magnets 3a r 3b and are deposited on the partition plate 13. Thereafter, the carrier is stored and transported between the blades by the action of the paddles 8. Then, when the master dollar 8 rotates, the carrier moves upward and is resupplied to the circumferential surface of the cylindrical body 2. On the other hand, a doctor blade 4 is provided on the downstream side of the paddle 8 with its tip spaced a predetermined distance from the circumferential surface of the cylinder 2. Among the carriers supplied to the photoreceptor drum 20, surplus carriers are scraped off by the doctor blade 4, so that an appropriate amount of carrier is always supplied to the circumferential surface of the photoreceptor drum 20. The excess carrier removed by doctor grade 4 is guided by guide 5 and dropped onto paddle 8.

In the area where the carrier falls from the lower end of the guide 5 to the paddle 8, a bias roller 6 and an electrode 7 are provided oppositely on both sides of the area where the carrier falls. A bias voltage having a polarity opposite to that of the toner and higher than the bias voltage applied to the cylindrical body 2 is applied to the roller 6, and the circumferential surface of the roller 6 at a position facing the electrode 7 is applied to the roller 6. is driven to rotate in a direction (upward) opposite to the direction in which the carrier is transported (falling). The electrode 7 is a round bar-shaped member provided parallel to the axial direction of the roller 6,
If the roller 6 is grounded, a low voltage (same polarity) bias voltage is applied to the roller 6 as well.

The carrier that has passed between the roller 6 and the electrode 7 and fallen onto the paddle 8 is mixed between the blades of the paddle 8 with the carrier that has been scraped off from the circumferential surface of the cylinder body 2 by the saw or paddle 8. , is again supplied to the circumferential surface of the cylindrical body 2. A wiper blade 6a is attached to the partition plate 13 with its tip slidingly in contact with the circumferential surface of the roller 6. The wiper blade 6a wipes off the toner adhering to the circumferential surface of the roller 6, and removes the toner between the partition plate 13 and the housing 12. It is made to fall into a passage formed between them and is fed to the discharge screw 10. Therefore, the discharge screw 10 discharges the toner knocked out from between the bristles of the fur brush 9 by the flickers 9a and 9b, and the toner and gold scraped off from the peripheral surface of the wiper roller 6 by the wiper blade 6a.

In the apparatus configured as described above, the photosensitive drum 200
When removing untransferred toner from the surrounding cloth, the untransferred toner is first swept away by the fur brush 9 and removed from the photoreceptor drum 2.
0, and then the flickers 9a, 9b
The ejection screw IO is knocked out from between the hairs of the hair.
It falls upward and is discharged by the discharge screw 10 and collected. Note that foreign matter such as paper dust from the overlapping transfer paper adheres to the circumferential surface of the photoreceptor drum 20 during transfer, and may enter the cleaning device location along with the untransferred toner. Such foreign matter is also removed from the circumferential surface of the photoreceptor drum 20 by the fur brush 9.

On the other hand, toner remaining on the circumferential surface of the photoreceptor drum 200 without being removed by the fur brush 9 is removed by the magnetic brush 1 on the downstream side.
The surface of the photoreceptor to which toner is not attached is supplied to the charging device 11. That is, the photosensitive drum 20
The toner on the circumferential surface of the magnetic brush l is magnetically attached to the circumferential surface of the cylindrical body 2 of the magnetic brush l, and due to the friction of the triboelectrically charged carrier,
Alternatively, the toner is electrostatically attracted to the cylindrical body 2 to which a bias voltage with a polarity opposite to that of the toner is applied, separated from the circumferential surface of the photoreceptor drum 20, and electrostatically attached to the circumferential surface of the carrier. The carrier sticks to the circumferential surface of the cylinder body 20 by the magnetic force of the magnet 3, and the carrier also rotates due to the rotation of the cylinder body 2, and reaches the installation position. Then, it is peeled off and removed from the outer peripheral surface of the cylinder body 2 by the carrier Fi paddle 8, and the paddle 8
The cylinder body 2 is stored between the blades of the cylinder body 2 and transported to the downstream side in the rotational direction of the cylinder body 2 by its rotation. During this rotation of the paddle 8, the carrier is stirred and triboelectrically charged. In addition, the cylindrical body 20 of the magnetic brush l is inspected from above by the doctor grade 4.
The carrier removed from the peripheral surface is guided by a guide 5 and falls, and during this falling, a bias voltage with a polarity opposite to that of the toner is applied between the roller 6 and the grounded electrode 7. Due to the electric field generated, the toner adhering to the surface of the carrier is transferred toward the roller 6 and adheres to the circumferential surface of the roller 6. Therefore, the carrier that falls from above the Tsukuduru 8 is clean and has no toner attached to it, and this clean carrier and the carrier that has been conveyed between the blades by the rotation of the paddle 8 are stirred and mixed. It is applied to the circumferential surface of the cylindrical body 2 on the Q downstream side in the rotation direction of the magnetic brush 1. Then, the excess carrier is removed by the doctor blade 4, and in the process of falling, the toner on the circumferential surface of the carrier is removed by the roller 6, and then the carrier is supplied to the paddle 8. On the other hand, the toner adhering to the circumferential surface of the row 26 is scraped off by the blade 6a and falls onto the discharge screw 10, and is discharged from the cleaning device by the discharge screw 10 and collected.

As described above in detail about the cleaning device of the present invention, according to the present invention, the carrier that functions as a cleaning agent in magnetic brush cleaning is removed from the magnetic brush 1 once. After the toner is collected by the roller 8, it is mixed with the clean carrier from which the toner has been removed by the roller 6 and is supplied to the magnetic brush l, so that the toner is constantly cleaned. The toner density does not increase above a certain value, and most of the carriers supplied to the circumferential surface of the photoreceptor 1 and the column 20 have sufficient ability to stick toner. A very high cleaning efficiency is maintained, and the carrier has an extremely long life. On the other hand, toner adhering to the circumferential surface of the carrier is formed between the roller 6 and the pole 7 while passing between them. Due to the electric field, the toner is transferred to the circumferential surface of the roller 6 and removed and collected, but by installing it near the grounded electric IM7'i roller 6, an extremely high electric field is created, so the toner removal efficiency ( The toner collection efficiency) is high, and sufficient toner removal efficiency can be obtained even if the bias voltage to the mater roller 6 is set to a low value, which is advantageous in terms of preventing leakage, noise, etc., and ensuring safety. Further, the toner electrostatically attracted toward the roller 6 adheres to the circumferential surface of the row 26 due to the adhesive force and electrostatic force on the circumferential surface of the roller,
The wiper blade 6a reaches the position where the wiper blade 6a is disposed without coming off the circumferential surface of the roller 6, and is securely removed. In this way, the toner collection performance is greatly improved, but since the rotating direction of the roller 6 is opposite to the direction in which the carrier passes (falling direction), the carrier having a higher specific gravity than the toner is transported around the roller 6. It does not stick to the surface, the amount of carrier wasted is significantly reduced, and the collected toner does not become impossible to reuse due to carrier contamination. Furthermore, the toner is
It is convenient for toner reuse because the toner removed from the circumferential surface of the photoreceptor drum 20 by the fur brush 9 and the toner removed by the magnetic brush 1 are concentrated, removed, and collected. It is. Furthermore, since the present invention does not use a blade or a web, there is no risk of damaging the surface of the photoreceptor, and it can be applied to photoreceptors with seams, regardless of the shape of the photoreceptor. , the present invention also performs cleaning with the magnetic brush 1 instead of cleaning only with the fur brush 9, thereby avoiding the occurrence of cleaning defects such as toner filming. Furthermore, by disposing a static eliminator on the upstream side of the cleaning device of the present invention to eliminate static from the surface of the photoconductor prior to cleaning the toner, the carrier and toner can be prevented from scattering. However, it is possible to further improve the cleaning efficiency.The present invention should not be limited to the specific embodiments described above, and various modifications can be made within the technical scope of the present invention. Of course it is.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG. 2 is a schematic diagram of a conventional magnetic brush cleaning device. (Explanation of symbols) 1: Magnetic brush 2: Cylinder 3: Magnet 6: Roller 7: T pole 8: Paddle 9: Fur brush 20: Photosensitive drum Fig. 1

Claims (1)

[Scope of Claims] 1. In a cleaning device for removing untransferred toner remaining on the surface of an image carrier, a magnet is built inside a cylinder, and a magnetic carrier is attached to the circumferential surface of the cylinder to clean the surface of the image carrier. A magnetic brush rotatably provided so as to rub, a supply means for supplying a magnetic carrier to the circumferential surface of the cylindrical body of the magnetic brush, and a collecting means for recovering the magnetic carrier from the circumferential surface of the cylindrical body. A cleaning device comprising: 2. In the above item 1, the magnetic carrier collected by the collecting means is configured to be fed to the supplying means, and the charging polarity of the toner is adjusted so as to face the feeding path of the magnetic carrier. A cleaning device comprising a roller to which a bias voltage of opposite polarity is applied. (1). . . 3. In the above item 2, an electrode is provided to face the roller via the feeding path, and the electrode is grounded or a voltage lower than the bias voltage of the roller is applied. cleaning equipment. 4. In the above item 2 or 3, the supply means:
The magnetic carrier collected by the collecting means and passed through the roller arrangement position and the toner removed from the surface of the image carrier by the rubbing of the magnetic brush are stirred and mixed to form the cylinder of the magnetic brush. A cleaning device characterized by supplying water to the circumferential surface of the body. 5. A cleaning device W that removes untransferred toner remaining on the surface of the image carrier includes a fur brush which is rotatably provided to rub the surface of the image carrier, and a magnet built into the cylindrical body. a magnetic brush provided in a rotating EJ function so as to adhere a magnetic carrier to the circumferential surface of the cylinder and rub the surface of the image carrier on the downstream side of the fur brush; and a circumferential surface of the cylinder of the magnetic brush. (2) A cleaning device comprising: a supply means for supplying an external carrier; and a recovery means for recovering the magnetic carrier from the circumferential surface of the cylindrical body. 6. In the above item 5, the magnetic carrier collected by the collecting means is configured to be fed to the supplying means, and the charging polarity of the toner is adjusted so as to face the feeding path of the magnetic carrier. A cleaning device characterized by having a roller to which a bias voltage of opposite polarity is applied. 7. In the above item 6, an electrode is provided so as to face the roller via the feeding path, and the electrode is grounded or a voltage lower than the bias voltage of the roller is applied thereto. cleaning equipment. 8. In the above item 6 or 7, the supply means is configured to slide the magnetic gear which has been collected by the collection means and passed through the roller arrangement position 7 and the magnetic brush. A cleaning device characterized in that the toner removed from the surface of the image carrier is supplied to the circumferential surface of the cylindrical body of the magnetic brush by stirring and mixing. 9. Any one of the above items 6 to 8. In item 1, a wiper blade that slides on the peripheral surface of the roller, a flicker whose tip is positioned between the bristles of the fur brush, and a wiper blade that scrapes off the peripheral surface of the roller. A cleaning device comprising: a discharge screw for removing toner and the toner between the brush bristles that has been knocked out by the flicker.