DE3810557A1 - DEVICE FOR REMOVING PARTICLE-DEVELOPER RESIDUES FROM A PHOTO-CONDUCTIVE ELEMENT - Google Patents

Abstract

A device for removing residual particles from a photoconductive member comprises a fur brush (12) in contact with the photoconductive member (110), a metal roller (14) in contact with the fur brush (12), a scraper blade (16) in contact with the metal roller (14), and a discharging device 114 downstream of the brushing apparatus. The fur brush (12) is maintained at a first biasing voltage, eg +50V, while the metal roller (14) is maintained at a second biasing voltage which is of the same polarity but greater in magnitude than the first biasing voltage, eg +150V. The fur brush (12) attracts residual particles from the photoconductive member (110) while the metal roller (14) attracts residual particles from the fur brush (12). The scraper blade (16) scrapes the residual particles from the metal roller, the particles falling into a conveying auger (20) for recycling. <IMAGE>

Description

The present invention relates to cleaning device for removing particulate ent winder residue from a photoconductive element an electrographic copier or printer. In particular, the present invention relates a cleaning device consisting of a com combination of a fur brush, a metal roller and a scraper to remove particulate Developer residues from a photoconductive Element of an electrographic printer or Copier.

In electrophotographic or xerographic Printing becomes a photoconductive element for printing drawing of a picture used. The photoconductive Element, which is typically in the form of a Tape or a roller becomes a sensitizer tion of the surface with an essentially even potential charged. in case of a Copier is the charged part of the photo conductive surface a reflected light image of an original to be reproduced puts. The photo is made in accordance with the Original document contained information areas on the photoconductive element as a latent elec trostatic image recorded.  

In the case of a printer using a computer is a similar process for Record information on the photoconductor element used. The charged part of the photoconductive surface becomes a photograph exposed, its shape by the input signals is controlled by the computer. This is how it works as a laser or light emitting diode arrangement, the Receives input signals from the computer as an optical Printhead and illuminates the photoconductive element with a photograph of a certain shape. Also here is a latent electrostatic image, wel ches the desired information areas speaks on the photoconductive element draws.

After recording the latent electrostatic This will be the image on the photoconductive element latent image developed by using an ent winder or toner. The Developer is from the latent electrostatic Image attracted and forms on the photoconductive Element is a powder image that corresponds to the latent corresponds to electrostatic image. The powder image is then on a sheet of the record mediums, e.g. a sheet of paper, transferred. Then the powder image on the sheet in the Image configuration through a variety of processes such as by fixation, permanently recorded net.

The above processes can be effected in that one near the other a number of stations in a row of the photoconductive element. The photo Conductive element is therefore usually one  Charging station, an imaging station, a Ent winder station and a transfer station vice ben, which are arranged one after the other. A discharge destation and a cleaning station are also attached to the photoconductive element to this to get ready for use again.

The term "electrographic printing device" as he is used here, and similar terms are like that to understand that they are both copy and Include pressure equipment. Such devices included a developer unit through which the photoconductive gene element toner is supplied. In typical Trap, the toner is contained in a magazine where it is mixed with a suitable charge carrier becomes. The carrier often contains iron or others Metal particles. The toner comes with the carrier mixed substance, he experiences a corresponding de electrostatic charge, through which it is without further transferred to the photoconductive element the latent elec develop trostatic image. Usually contains the electrographic printing device also a Reini device for removing the toner and other developer particles after transfer of the developed image on the sheet of the record medium on the surface of the roller or the Band. In some cases it is Cleaning device in the developer unit integrated, which alternately either develop performing a cleaning function.

In the past, lead has been removed developer particle from the photoconductive Belt or roller a variety of devices  and methods used. Therefore the Reini closes supply device often a brush that the Be side of the developer particles. The brush has a length that is essentially the width of the corresponds to the photoconductive element this way the entire photoconductive element is cleaned. The cleaning brush consists of a suitable material for attracting the toner particle and is compared to the photoconductive Ele ment arranged in such a way that it Touches the surface and thereby the remaining Removed developer material.

However, cleaning brushes are provided for the Purpose not entirely satisfactory. Cleaning brushing alone, especially after long use, when removing all residual particles from the photo conductive element not effective. The distance of residual particles that are on the cleaning brush accumulated is always a problem. Farther it will, even if devices for Removal of such residual particles are provided, after long use difficult the developer part from the cleaning brush to the middle office remove most areas. This then runs the Cleaning process due to an uneven con clocks with the photosensitive element irregular moderately. To overcome this problem, one has complicated devices, e.g. the one according to US Patent No. 45 71 070 (Tomita), suggested gene.

Another method of cleaning the photo conductive element is a stripper to the  photoconductive element. The scraper which is typically made of a hard rubber material exists, is against the photoconductive element ge it presses and frees it from remaining on it toner particles. For example, US Patent No. 45 68 175 (Inowa et al) a wiper device for removing toner particles back on the surface of a photoreceptor remained.

Such stripping devices are also not complete satisfactory. First, the problem is that Scraper blade in even contact with the To keep the surface of the photoconductive element. Irregularities occur especially after a long time moderate across the width of the scraper blade away so that the scraper is no longer in even contact with the photoconductive Ele ment remains. Second, to clean the stripper used in photoconductive element in many cases, the photoconductive surface scratch. This is especially the case if it is the developer is concerned with a two-component Developer that contains ferrite particles. The Combination of wipers and hard ferrite particles tends to the delicate surface of the photo to scratch the conductive element. Third, must the cleaning sheet at a fixed angle held to the photoconductive element. This implies the use of relatively complicated arrangements ahead. See, for example, the arrangement tion described in U.S. Patent No. 45 68 175 (Inowa et al) is described.  

Accordingly, there is an object of the present the invention in a cleaning device for Removal of residual developer particles from one to give photoconductive element to the hand not among the shortcomings of the previously known Reini cleaning brushes and cleaning sheets suffers.

In particular, there is an object of the present Invention in the creation of a cleaning device device for removing developer material from a photoconductive element that is not a big to leranzen requires, as with the previous Rei cleaning brushes and cleaning sheets was the case.

Another object of the present invention consists in creating a cleaning device device, which is a return of the developer particles, that remained on the photoconductive element were allowed.

Another object of the present invention be stands in the creation of a cleaning device, which is simple, easy to manufacture and on an interchangeable photoconductive tape can be brought.  

According to the present invention, one is Particle-shaped cleaning device developer residues from a photoconductive elect ment provided. The cleaning device closes a cleaning brush that works with the photoconductor capable element is kept in contact. A the brush is first pretensioned applied to the residual particles from the photoconductive Pull the element onto the cleaning brush. A Transfer element is with the cleaning brush kept in touch. A second bias will appear applied to the transmission element. This second Bias has the same polarity, but is greater than the first bias applied to the Reini supply brush is applied. This will make the rest left on the cleaning brush Developer particles on the transfer element drawn. A removal element, e.g. a Scraper is then attached to the transmission element created so that on the transmission element drawn developer particles are removed.

A preferred embodiment of the present Invention includes a fur brush that matches the photoconductive element is kept in contact. A metal roller serves as a transmission element for Removal of the developer particles from the fur coat ste. A scraper removes the developer particles from the metal roll. One is attached to the fur brush Bias of about +50 V applied to the rest subtract particles from the photoconductive element,  and a second bias voltage of approximately +150 V is applied the metal roller applied to developer particles from the fur brush onto the metal roller.

In a further preferred embodiment of this invention includes the cleaning device continues to cooperate with the scraper Slug. The snail takes it through the wiping Development part removed from the metal roll and transport them to a station where the process, e.g. the developer unit, again can be supplied.

An embodiment of the invention is in the Drawings are shown and will be described in more detail below described. Show it

Fig. 1 shows a preferred embodiment of the cleaning device according to the present invention.

Fig. 2 is a schematic representation of an electro-graphic printing device with the cleaning device according to the present invention.

In Figure 1 , a cleaning device is shown, which corresponds to the basic principles of the present invention. A cleaning device, generally shown as 10 , is arranged as a unit or station opposite the photoconductive element 100 . The cleaning device 10 is arranged behind the transfer station in the electrographic printing device. In this case, the photoconductive element 100 includes a photoconductive belt 110 which moves around the roller 111 in the direction of the arrow.

It is desirable that the photoconductive element 100 is an interchangeable photoconductive tape in the form of a cassette, as described in the application filed with serial no. 7 18 947, filed April 2, 1985. This cassette is suitable for vertical mounting in an electrographic printer / copier of the type described in the application with the serial number. 7 00 813, filed on February 11, 1985, is described. Both applications have been transferred to the assignee of the present application and both are referred to below. According to the present invention, the cleaning device 10 is attached directly to the disposable cassette and is removed together with the cassette when the life of the photoconductive tape has expired.

The cleaning device 10 includes a cleaning sleeve 12 with a length that speaks essentially the width of the photoconductive belt 110 ent. Such cleaning brushes are well known to those skilled in the art and are often made from a fur material such as a suitable acrylic material. A metal roller 14 serves as a transmission element which comes into contact with the fur brush 12 . A scraper 16 is net angeord that it touches the metal roller 14 .

A screw 20 is provided in the housing 18 of the cleaning device 10 . The task of the screw 20 is to remove developer particles which have been stripped from the metal roller so that they are eliminated or can be fed back into the process.

The cleaning device is housed in a housing 18 . The cleaning device 10 thus forms a separate unit and, if necessary, can be replaced separately from the rest of the cassette. In normal use, however, it is expected that the cleaning device 10 is replaced together with the cassette after a corresponding period of use.

In operation, a first bias of approximately +50 V is applied to the fur brush 12 . A second bias of approximately +150 V is applied to the metal roller 14 . As the photoconductive member 110 rotates, residual developer particles that remain on the belt after the powder image is transferred to the paper are swept away by the fur brush 12 . The particles are drawn onto the fur brush due to the first bias applied to the fur brush. The residual particles remaining on the fur brush 12 are then drawn onto the metal roller 14 by the second pretension, which is greater than that applied to the fur brush. The residual particles are then removed while the metal roller 14 is together with the fur brush 12 and the photoconductive belt 2 rotates, stripped from the metal roller 14 by the scraper 16 and fall into the passages of the screw 20 . It should be noted that the stripper 16 does not come into contact with the sensitive photoconductive element. The screw 20 rotates and thereby transports the developer particles out of the interior of the cleaning device 10 , and the toner particles are then either returned to the process or removed, but preferably reintroduced into the process.

Fig. 2 is a block diagram showing the basic components of an electrographic printer incorporating the novel cleaning device according to the present invention. The design of this electrographic printer is similar to that of the printer that was registered with the serial no. 7 00 813, filed on February 11, 1985, and which contains the vertically attached disposable cassette which is described in the patent application with the serial no. 7 18 947, is sufficient on April 2, 1985, is described.

As shown in the drawings, this printer includes a photoconductive belt 110 which is rotated clockwise over rollers 111 and 112 .

Along the right side of the belt, as shown in Fig. 2, there are the cleaning unit 10 , the extinguishing lamps 114 , the main charger 113 and an optical printhead 115 . Developer 116 is on the left side of the unit. This unit contains a toner cartridge 118 for easy handling. At the top of the belt path is a transfer unit 119 that generates an electric field to pull toner from the photoconductive belt 110 onto the underside of sheets of paper that pass through the image transfer area 125 .

The copying material, for example paper, is taken from one of two convenient paper cassettes 120 and 121 . The paper is fed via one of two papers because of 122-1 or 122-2 to the image transfer area 125 which lies between the upper roller 111 and the transfer unit 119 . The paper is then fed from the image transfer area 125 with the aid of a vacuum transport unit 124 to a fixing unit 123 and finally placed in an output tray 125 .

The operation of the printer includes a single revolution of the tape per copy made. During this rotation, the tape is evenly charged when running through the main charger 113 . A latent image is generated by an optical printhead 115 , which can be either a laser or a light emitting diode arrangement. The optical printhead is used to discharge selected parts of the uniformly charged photoconductive tape as it moves past the optical printhead. The resulting latent image is formed by applying the toner from the developer unit 116 .

As shown in the illustrations, the toner is only deposited on the discharged parts of the photoconductive belt. The tape then runs into the transfer area, where the developed image is transferred to the underside of the paper. In the transfer area 125 , the transfer unit 119 is used to generate an electric field which pulls toner from the photoconductive belt onto the underside of the paper.

As the belt continues to rotate after the image has been transferred, it runs directly into the area of the cleaning device 10 . The remaining particles are removed from the belt as described above and the belt is evenly discharged by the erase lamps 114 . This prepares the tape for the next copy.

The cleaning device according to the present invention successfully removes the remaining ent winder particles from the photoconductive tape without subject to the problems of cleaning before had directions of earlier designs.

While the invention with reference to spec le embodiments have been described, this applies but only as an illustration and should not be considered Limitation of the scope of the invention be interpreted.

Claims (11)

1. Cleaning device for removing residual particles from a photoconductive element in an electrographic printing device, characterized by :
Brushing devices which are in contact with said photoconductive element and are held under a first bias in order to remove said residual particles from said photoconductive element,
Transfer devices in addition to the aforementioned brush devices, characterized in that the aforementioned transfer devices are held under a second bias in order to subtract the aforementioned residual particles from the aforementioned brush devices, and in that the aforementioned second bias has the same polarity as the aforementioned first bias, however is larger, and
Devices for removing the above-mentioned residual particles from the above-mentioned transfer devices. 2. Cleaning device according to claim 1, characterized characterized in that the brush device mentioned a fur brush. 3. Cleaning device according to claim 1, characterized characterized in that the aforementioned transfer directions contain a metal roll.   4. Cleaning device according to claim 1, characterized characterized in that the aforementioned device for Particle removal contains a scraper. 5. Cleaning device according to claim 1, characterized characterized in that the aforementioned first bias approx. +50 V and the mentioned second bias voltage approx. Is +150 V. 6. Cleaning device according to claim 1, further characterized in that it is mentioned with the Removal device connected removal directions for removing the remaining part Chen from the mentioned removal devices having. 7. Cleaning device according to claim 6, characterized characterized in that the abtransportvor mentioned directions include a snail. 8. Cleaning device for removing residual developer particles from a photoconductive element in an electrographic printing device, characterized by:
a brush in contact with said photoconductive member to which a first bias is applied to pull said residual particles from said photoconductive member,
a metal roller next to said brush, to which a second bias is applied in order to pull off the above-mentioned residual particles from said brush, characterized in that said second bias has the same polarity as the first bias but is greater, and
a scraper next to the aforementioned metal roller to remove the residual particles from the aforementioned metal roller. 9. The cleaning device according to claim 8, further characterized in that they are one with which he Scraper connected snail for removal port removed by the stripper mentioned Contains residual particles. 10. Cleaning device according to claim 9, characterized characterized in that the aforementioned first bias approx. +50 V and the mentioned second bias voltage approx. Is +150 V. 11. A method for removing residual developer particles from a photoconductive element in an electrographic printing device, characterized by:
brushing said photoconductive element with a brushing device, while at the same time a first bias is applied to said brushing device to remove said residual particles from said photoconductive element,
the transfer of said residual particles from said brushing devices with a transfer device while a second bias is applied to said transfer devices to subtract said residual particles from said brushing devices, characterized in that said second biasing has the same polarity as the mentioned first preload, however, is greater, and
the removal of the residual particles mentioned from the transfer elements mentioned.