DE3810558A1 - IMPROVED ELECTRICAL PRINT / COPIER WITH PHOTO-CONDUCTIVE TAPE - Google Patents

Abstract

In an electrostatographic printer of the kind in which an image is applied to the under surface of a horizontally indexed substrate, the photoreceptor (110) is contained in a readily replaceable module, which module includes a cleaning unit (100) for removing residual toner from the photoreceptor surface. <IMAGE>

Description

The invention relates to an electrographic printing or copier with simplified paper web. In particular, the present invention relates to a electrographic printer or copier, which with a vertically arranged photoconductive Belt unit works with simplified paper web, whereby on the underside of the copy sheet latent electrostatic image is developed.

For electrographic or xerographic printing becomes a photoconductor to record an image capable element used. The photoconductive Ele ment, which is the shape of a ribbon or a Roller can be used to raise awareness of the Surface with a substantially uniform Potential charged. In the case of a copier becomes the charged part of the photoconductive upper surface of a reflected light image exposed to reproducing originals. The light image is created in accordance with the original document information areas on the photoconductive gene element as a latent electrostatic 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 attaches 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.

An example of such an electrographic print device is in the granted registration with the Serial no. 7 00 813, filed February 11 1985. The electrographic printing / Copier, which in the patent concerned registration is described, works with a photo conductive tape unit in the form of a disposable cassette te, which in the issued registration with the serial No. 7 18 947, filed April 2, 1985, be wrote and verse with corresponding claims hen is. That in the registration with the serial no. 7 00 813 described printing / copying machine works also with the combined developer and rei unit, the subject of the granted application with the serial no. 7 18 946, filed on April 2, 1985. All of these aforementioned patents Registrations were made to the current transferee transferred and applied to them all in this patent application referred.

The registration number with the serial no. 700 813 described electrographic printer / copier has a simplified paper web, which by the The top of the device is accessible. In this elec The trographic printer / copier is the photo Cassette containing conductive tape vertically brings, and on the bottom of the copy paper creates a latent image while the paper moved over the photoconductive belt unit and with this comes into contact.  

The relevant electrographic printing device changes two turns of the photoconductive tape each produced copy. It is used to make about Suitable for 12 copies per minute. During the first The tape becomes the circulation of the photoconductive tape evenly charged, and with the help of an opti printhead is on the surface of the photo conductive tape creates a latent image. The latent image thus generated is obtained by plotting Work toner out of the "Develop" mode developed the developer / cleaning unit. The Band then enters the transmission area where the developed image on the bottom of the paper or other copy material becomes. A transmission is generated in the transmission area an electric field, which the Toner from the photoelectric tape to the bottom of the paper. This will be the first round of the Tape ends while the paper turns into a Fusing unit moves and into a discharge tray is thrown.

During the next belt revolution, the belt will be for preparing to make the next copy. The Main charger and the optional printhead are blocked while an extinguishing lamp is activated and the developer / cleaning unit in operating mode "Cleaning" is switched. So while the tape after the image transmission continues, that will discharge photoconductive tape through an erase lamp, and the excess toner is removed using a conventional electrostatic process from the Developer / cleaning unit removed. Thereby the tape for the next copy will be the next Belt circulation made ready.

The object of the invention is the performance of above-described electrographic printer / To increase the copier and remove the device change that thereby a "one-step device" becomes. This means it would be desirable if the electrographic printer / copier only one single circulation of the photoconductive tape ever copy would require. To this This would double the performance of the device.

This task is done by an electrographic Pressure device solved, the design of the device is the same as that in the issued registration with the Serial no. 7 00 813, filed February 11 1985, was described, but in the immediate a separate and behind the transmission station independent cleaning unit is provided. A electrographic printing device according to the present The invention thus comprises a housing, a cover to cover the upper part of the housing, a copy material source and a discharge tray for holding of the copy material after printing. The pressure device also contains a photoconductive element on which the following units are arranged one after the other: a charging unit for even charging the photoconductive element, an optical print head to discharge selected parts of the photoconductive gene element, so that there is a latent electro static image is created, a developer unit  for the development of the latent electrostatic Ab bildes, a transmission unit for the transfer development of the developed electrostatic image on paper or other copying material, a separate cleaning unit for removal of rest cher developer particles from the photoconductive Element and an extinguishing lamp for the even Discharge the photoconductive element to it for to get the next copy ready.

As with the printer / copier according to the registration with the serial no. 7 00 813 the copier moves material along an essentially flat paper track near the top of the housing, so that through Lift up the lid to access the paper web becomes possible. The photoconductive element is below arranged half of the flat paper web and comes with the bottom of the copy material in one in the flat paper web arranged transmission area in contact to the powder image on the bottom to transfer the copy material.

It is desirable that the photoconductive element contains the photoconductive tape unit in the form of a one-way cassette, which is described in the aforementioned application with serial no. 7 18 947 filed on April 2, 1985, described and provided with the corresponding claims. This photoconductive tape unit is mounted vertically in the electrographic printer / copier. It contains a sheet guide on the top of the frame, which limits a horizontal transmission area of very short length under the top of the housing.

While electrographic printing / copying machines be were written, the separate and independent Rei units included - see e.g. B. U.S. patent No. 39 76 375 (Kurita et al) - has been previously not yet the special state of the art construction and the special arrangement of the above descriptions described units.

The figure shows a schematic representation an electrographic printer / copier According to an illustrative embodiment of the present invention.

The figure is a block diagram showing the basic components of the electrophotographic printer according to an aspect of the present invention. Such printers typically include a photoconductive element, which is a tape 110 in the illustrated embodiment. The latter runs clockwise around rollers 111 and 112 . Along the right side of the band, as shown in FIG. 1, there are a cleaning unit 100 , extinguishing lamps 114 , a main charger 113 and an optical print head 115 . The developer unit 116 is located on the left side of the belt. This unit contains a toner cartridge 118 for easy handling. At the top of the belt path is a transfer unit 119 which creates an electric field to draw 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 removed from one of two practical paper cassettes 120 or 121 . The paper is guided along one of the two paper webs 122-1 or 122-2 to the image transfer area 125 between the upper roller 111 and the transfer unit 119 . From the image transfer area 125 , the paper is then fed with the aid of a vacuum transport unit 124 to a fixing unit 123 and finally ejected into a discharge tray 125 .

The operation of this printer involves only one revolution of the ribbon 110 per copy made. During this cycle, the tape is charged evenly as it passes the main charger 113 . A latent image is generated with the aid of an optical printhead 115 , which can be either a laser or a light-emitting diode arrangement. The optical printhead discharges selected portions of the evenly charged photoconductive belt 110 as it moves past the optical printhead. The latent image thus generated is then developed by applying toner particles from a developer unit 116 . In the illustration, the toner is applied only to the discharged portions of the photoconductive belt 110 . The tape then runs into the transfer area 125 , where the developed image is transferred to the underside of the paper or other copy material. In the transmission area 125 , the transmission unit 19 is used to generate an electric field which pulls the toner from the photoconductive belt onto the underside of the paper.

After the developed image is transferred to the underside of the paper or other sheet material, the photoconductive tape must then be made ready for the next copy. The photoconductive belt 110 , which continues the same cycle, is cleaned by means of the cleaning unit 100 . The erase lamps 114 are activated to evenly discharge the photoconductive tape. Thus, while the belt continues to circulate after image transfer has taken place, the excess toner is removed from the cleaning unit 100 and the belt is discharged by the erase lamps 114 . This prepares the belt for a new charge by the main charger 113 to make the next copy.

As noted above, it is a feature of the present invention that the copy is made along the bottom of the paper. This is achieved by placing the photoconductive tape 110 under the paper web. In the illustrative embodiment shown in FIG. 1, the transfer area lies above the roller 111 , and the paper runs into the area such that its underside comes into contact with the belt 110 .

In order to avoid contamination of the copy after the image transmission, the printed paper is fed to the conventional fixing unit 123 by means of a vacuum transfer unit 124 , the only contact of which is with the upper, unprinted side of the paper. The fixing unit 123 serves to fix the toner on the paper by heating the paper.

After the printed copy has left the fixing unit 123 , it runs into the discharge tray 125 with the printed side facing downward. An advantage of this arrangement is that the printed copies are automatically collated. Another advantage of the arrangement of the photoconductive belt 110 below the paper web is that the paper web is then easily accessible and there is the possibility of clearing paper jams more easily. As can be seen in Fig. 1, the paper web runs along the top of the printer and is accessible by simply lifting the device cover 130 .

The cleaning unit 100 may include one of a number of conventional devices that have previously been used to remove residual toner particles from photoconductive elements. The cleaning unit 100 can consist, for example, of a cleaning brush or a scraper. The cleaning unit 100 preferably consists of an electrostatically charged cleaning device. Such devices are held under an appropriate bias, due to which they can pull toner particles from the photoconductive element. In the preferred embodiment, the cleaning unit 100 includes one of the electrostatic cleaning devices described in the applications entitled "DEVICE FOR REMOVING REMAINING DEVELOPER PARTICLES FROM A PHOTO-CONDUCTIVE ELEMENT" (device for removing residual developer particles from a photoconductive member) or "TONER CLEANING UNIT" ( toner cleaning unit), which are submitted simultaneously with the present application. These applications have been transferred to the common assignee of the present application and are referred to here. These applications relate to cleaning units which can be conveniently attached to a photoconductive belt unit such as that shown here.

As a result of using a separate and independent The cleaning unit can be the electrographic Printer / copier, which in the registration with the Se rien-No. 7 00 813 is described, from a "two Step device "converted into a" one-step device " become, i.e. there will be one copy per circulation of the photo conductive tape. This doubled practically the performance of the machine of about 12 pages per minute to about 24 pages per minute.

Appropriate adjustments can be made on the above devices conditions are made to a printing device to achieve with duplex features. With the help of this Adjustments first run one side of the copy materials past the photoconductive belt and then the other side of the copy material runs on the photo conductive tape over so that powder images on both sides of the copy material are transferred. With the use of a separate and independent  The cleaning device is Ko per printed page only one circulation of the photoconductive material Tape required. The device with duplex features is able to print 24 pages per minute work.

The cleaning unit 100 is housed in its own Ge housing. It is desirable to attach them to the photoconductive tape unit as shown. In the event of a fault, the cleaning unit 100 can be replaced as a separate unit. However, this may make it necessary to realign the parts. In normal operation, it is assumed that it will be eliminated with the rest of the disposable cartridge.

While the invention with reference to a special embodiment was described, served this is for illustration purposes only and should not as a restriction of the scope of the Erfin be interpreted.

Claims (7)

1. Electrographic printing device for producing hard copies with information to be recorded, characterized by :
an open housing,
a cover to cover the top of the housing,
a copy material source and a discharge tray for receiving the mentioned copy material after printing,
a copy material path along which said copy material moves between said source and said discharge tray, said copy material path being substantially in a single plane in said housing near the top thereof so that said cover is lifted by lifting said cover Copy material web becomes accessible,
a photoconductive member for storing a latent electrostatic image of the information to be printed, said photoconductive member being below said plane copy material sheet and coming into contact with the underside of said copy material in a transfer area located in said plane copy material sheet around to transfer the aforementioned latent electrostatic image to the underside of the copying material mentioned, while the copying material mentioned comes into contact with the mentioned photoconductive element essentially only in the mentioned transmission range,
a charger, a selective discharge unit, a development unit, a transmission unit, a cleaning unit and an extinguishing unit, which are arranged one behind the other on the aforementioned photoconductive element,
wherein said electrographic printing device produces a printed side of the recording material per revolution of said photoconductive element. 2. Electrographic printing device according to claim 1, characterized in that the photoconductive Element is a photoconductive tape. 3. Electrographic printing device according to claim 2, characterized in that the photoconductive tape is mounted vertically. 4. Electrographic printing device according to claim 3, characterized in that the aforementioned photoconductor capable tape is part of a disposable cassette. 5. An electrographic printing device according to claim 4, characterized in that the aforementioned Reini unit attached to the aforementioned cassette is.   6. An electrographic printing device according to claim 5, characterized in that the aforementioned Reini supply unit in a corresponding housing brought. 7. An electrographic printing device according to claim 1, characterized in that the selective discharge unit includes an optical printhead.