DE2337221A1 - COPY DEVICE - Google Patents

Description

K 2239 / Gbm 646 ¹ FP-Dr.Gr-cb July 17, 1973

Description for the registration of

KALLE AKTIENGESELLSCHAFT Wiesbaden-Biebrich

for a patent

Copier

The present invention relates to an electrophotographic Copier, as described in more detail in the preamble of the main claim.

In known electrophotographic copiers which operate on the principle of toner image transfer, copier drums with a selenium layer are used. Your copier drums have a vapor-deposited selenium layer on their cylindrical surface. With these devices, at the end of the useful life of the selenium layer, it is necessary to exchange the entire copier drum and replace it with a new one. This requirement arises from the fact that the selenium layers ^have a limited useful life. ^e J _O988 ß /! _{1 8} Q

There are also copier machines known that one have photoconductor foil stretched around a copying drum. These In this case, the film can be guided to the outside over the copying drum from a supply reel arranged in the interior of this copying drum be arranged to run and v / ground back into the interior of the drum on a take-up reel. These Arrangement enables an automatic replacement of the photoconductor foil at the end of its useful life. This mechanically elaborate system is expensive and is only used for high-performance copier machines, which in any case are constantly being used by maintenance personnel need to be looked after.

The object of the invention is to provide a simple electrophotographic To create copier that works with a photoconductor film and allows easy replacement of the photoconductor film and at the same time has as small an image-free area as possible on the copying drum.

The task is solved by an electrophotographic copier, as it is marked in more detail in the main view. Preferred Embodiments are defined by the subclaims.

The invention will be explained in more detail below with reference to the figures of the drawing. ·

Show it:

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Fig. 1 is a schematic sectional view of an inventive Copier,

2 shows an enlarged illustration of an embodiment of the photocopying drum,

FIG. 3 is a longitudinal view of the photocopying drum shown in FIG ,

Fig. 4

and FIG. 5 shows a copying drum in the open and closed state, the tensioning mechanism for the photoconductor and the locking mechanism are omitted are,

Fig. 6

and 7 a further embodiment of the photoconductor drum also without clamping and locking mechanism.

In Fig. 1 is a schematic section of an electrophotographic Copier shown, all known process stages are only indicated schematically and only the photocopying drum is shown in more detail. On the actual photocopying drum 1 there is a photoconductor film 2, which is still in is arranged in a manner to be described in more detail in this drum housing. The photoconductor drum is in a housing (not shown) or frame arranged rotatably and can in this way be moved past the various electrophotographic process stations will. The photoconductor 2 is, for example, with With the help of a scorotron 3, uniformly charged and

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Exposure station 4 exposed imagewise. In the process, a latent charge image corresponding to the original is formed on the photoconductor 2, which is grounded on the rear side. This charge image is made visible in the development station 5, for example a cascade development unit or a magnetic brush station, in a known manner. The resulting visible image is transferred from the photoconductor in a transfer station 6 to a copy material 7. If necessary, the transferred image is fixed in a fixing station 3 on the recording material, for example paper. In order to remove remaining toner residues from the photoconductor 2, a cleaning station 0 is provided, which is shown schematically in FIG. 1 as a brush roller with a suction device. This copy cycle can be repeated any number of times.

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Reference is now made to FIGS. 2 and 3 for a detailed description of the photoconductor drum. In these figures, the photocopying drum is shown in a longitudinal and a cross section. The photocopier drum 1 has a slot 13 which extends over its entire length 1 Vfigs of a cylinder jacket 1 inie. The photocopying drum 1 is designed in such a way that the internal tension of the material, without external influence, would lead to the slot 13 being closed, i. E. the edges of the photocopying drum 1 forming the slot would lie on top of one another. Inside the slotted photocopying drum 1 there is a fixedly connected to the copying drum 1 on each side of the slot

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Main bearing 15 and a counter bearing 16. Inside the counter bearing 16 is an externally for example with the help of a hexagon screw rotatable eccentric 17 mounted. This eccentric or this eccentric nerve interacts with two guides 14 on both sides of the occupied by the photoconductor film web 2 Area are arranged. By turning the eccentric shaft 17, the main bearing 15 and the counter bearing 16 are pushed apart, so that the slot 13 opens. A further rotation of the eccentric shaft 17 or its turning back leads to that the drum 1 closes the slot 13 again due to its internal tension.

The drum is closed at both ends by cover parts 25 and 25 which can have sealing rings 23 or 24 on a projection protruding inwardly into the drum. When the eccentric shaft 17 is turned back, on the one hand the slot 13 closes and on the other hand the drum 1 sits firmly on the seals 23 and 24.

In the two cover sections 25 and 26 is still a slotted Tension shaft 8 supported. This expansion shaft can also can be turned from the outside with the aid of a hexagon screw 23. It is also possible to use the expansion shaft 3 instead of in covers 25 and to be stored in guides 19, as indicated in FIG.

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The photoconductor film can be inserted into the slot 20 in the tensioning shaft 18 2 and by rotating the tensioning shaft 18, the photoconductor is pulled tightly on the circumference of the drum 1.

The guides 14 in the main bearing 15 and in the counter bearing 16 intervene, serve on the one hand to transmit the to open the Drum 1 required force through the eccentric shaft 17, on the other hand to the fact that the drum 1 always assumes the same external shape as before opening. The dimensionally accurate surface of the The copier drum is essential to obtain good copies.

The tensioning shaft 18 is preferably arranged so that it is secured against unintentional rotation. This can be done with the help be done by latches or in some other known manner. Inside the copying drum Ί there is a balancing mass as a counterweight 12 attached. *

The insertion or replacement of the copying foil is done with the copier according to the invention in the following way:

First, by turning the eccentric shaft 17, the slot 13 so far open that the copying film can be easily passed through it in a double position. The two ends of the copy film are guided through the slot 20 in the tensioning shaft 18. Then the tensioning shaft 13 is rotated until the Copy film 2 is firmly seated on the outer surface of drum 1. then

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the eccentric shaft 17 is slowly rotated and the tensioning shaft 18 rotated further so that the photoconductor 2 sits firmly on the outer surface of the drum 1 afterwards. By your own The tension in the slotted drum 1 closes itself off and finally clamps the photoconductor 2 in the slot 13. At the same time, this creates a tight seal that allows penetration prevented by electrophotographic developer material. In addition, the image-free slot caused by the inward leading of the photoconductor is reduced to a minimum. The taking out the photoconductor film 2 happens in reverse order, d. H. the eccentric shaft 17 is first loosened, and also at the same time the tensioning shaft 18 is turned back a little, and then the tensioning shaft 18 is turned back until the photoconductor film 2 can be pulled out.

Instead of a photocopy drum 1, which is due to its own Tension able to close the slot 13, a drum can also be used, with the help of springs attached from the inside 35 to be drawn. This is shown schematically in FIGS. 4 and 5. The drum 1 consists in this case of thin-walled Material. Instead of an overall elastic drum 1, the drum can also consist of two sections 31 and 32, which essentially have the shape of half hollow cylinders and are connected to one another by a narrow elastic bridge part 33 are. Such a construction is shown schematically in FIGS

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Figures 6 and 7 are shown in which the drum is shown in the open and closed condition. With this construction is very exact dimensional accuracy with good openability and closability connected to the drum.

Finally, it is also possible to design and arrange the drum and the expansion shaft in such a way that by rotating the expansion shaft and the tension thus exerted on the photoconductor closes the drum itself. In this case, this is not applicable Requirement of an eccentric shaft.

In addition to the solution to the problem, the following advantages of the subject matter of the invention are to be emphasized:

Closing the drum with only a single gap brings a sure conclusion «It yourself. This is especially true with liquid Toners, in which the penetration of toner into the interior of the copier drum, leads to unpleasant soiling of the Device. In addition, the copying foils can be changed in a simple manner without a special scanner.

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Claims (9)

Claims 1. / Electrophotographic copier with a photoconductor flag, which are arranged on the outside on a drum-shaped guide part is and its ends in the interior of the drum-shaped guide part range and are fixed there, with a frame in which the drum-shaped guide part rotates with the photoconductor is arranged and with a charging, an exposure and a transfer station, in which the outside on the drum-shaped Guide part arranged photoconductor in each case charged, exposed imagewise and that located on the photoconductor Image can be transferred to a recording material, characterized in that the drum-shaped guide part (1) has a single, narrow * longitudinal slide (13) through which the photoconductor track (2) with its two end sections inside of the guide part (1) is performed that the drum-shaped guide part (1) is designed so compressible that the edges of the drum-shaped guide part, the limit the longitudinal slot (13), in tight contact with the double there lying photoconductor track (2) arrive. 2. Copier according to claim 1, characterized in that the drum-shaped guide part (1) at least in part of its Is designed to be flexible around the circumference. 400886/1190 3. Copier according to claim 1, characterized in that the drum-shaped guide part (1) as a slotted cylindrical Sleeve is formed from a flexible material. 4. Copier according to claim 2, characterized in that the drum-shaped guide part has two sections (31, 32) one having cylindrical sleeve made of rigid material, which together by a narrow elastic portion (33) of the same outer Cylinder configuration with the formation of a slotted cylinder: are connected. 5. Copier according to one of claims 1 to 4, characterized in that that in the interior of the drum-shaped guide part at least one spring (36) is arranged, one for closing of the slot (13) sufficient force on the drum-shaped Exercises leadership part. 6. Copier according to one of claims 1 to 5, characterized in that that inside the drum-shaped guide part (1) Tensioning devices (18, .20) for holding and tensioning the photoconductor track are arranged. 7. copier according to claim 6, characterized in that the clamping devices have a slotted clamping shaft (20), which is secured against backward rotation. 409886/1190 8. Copier according to one of claims 1 to 7, characterized in that inside the drum-shaped guide part (1) an externally operable device (14, 15, 16, 17) for opening and closing the slot (13) of the drum-shaped guide part (1) is provided. 9. Copier according to claim 8, characterized in that the device for opening and closing the drum-shaped guide part (1) consists of a main bearing (15) and an abutment (16), each on adjacent sides of the slot on the drum-shaped guide part (1) are attached, as / ie consists of guides (14) which are arranged to the side of the area occupied by the photoconductor (2) and ensure safe guidance of the two ends of the drum-shaped guide part (1) forming the slot (13), and that an eccentric cam (17) is provided in the interior of the drum, the rotation of which causes the guides (14) to open or close the slot (13). [■ 409886/1 190