DE1093192B - Equipment for the production of copies by the electrophotographic process - Google Patents

Description

Device for making copies after the electrophotographic Method The invention relates to an improved apparatus for duplicating by the electrophotographic method.

Such an apparatus usually uses an electrophotographic one Plate; usually this consists of a metal plate covered with a layer of selenium, which is to be attached to the circumference of a cylinder. This cylinder is during of working according to the method constantly in rotation, so as to be attached to it Plate one after the other at a loading point, an exposure point, a development point and a transfer point.

In these continuously operating devices, the image becomes projected onto the moving curved electrophotographic platen what a Simultaneous movement of the original makes it necessary during the exposure process there is no relative movement of the projected image. Because you only have a picture project onto a narrow transverse strip of the cylindrical surface of the plate the complete image must be built up on the plate as a series of strips will. Experience has shown that such a projection system occurs when setting the optical projection means on considerable difficulties. Also has the person operating the device has insufficient control over the degree of exposure, especially when projecting continuous films.

The object of the invention is an electrophotographic device where the operator has complete control over the manufacturing process can exercise every single copy and adjust in every exposure possible in terms of size, position, coverage, intensity and repetition is.

In an apparatus for making copies after the electrophotographic Process in which the material supporting the electrophotographic layer for the purpose of Charging, exposure, development and fixing and transfer to suitable transfer material by means of a transport drum rotatable about its longitudinal axis is moved, the cross section of the transport drum according to the invention is a straight one Polygon, with the drive: the transport drum by known devices intermittently can be done.

The electrophotographic plates used with your device in accordance with the present invention Invention find use, can be metal plates coated with selenium, or they can consist of paper or similar carrier material that is unilateral with a suitable photoconductive, insulating material is coated. Such plates can comfortably be placed on the surfaces of the polygonal drum and held on it will; they are used repeatedly during the work process. Each Plate can also be attached in a suitable manner so that it is with the Drum makes one full or partial revolution and then removed from it will.

The polygonal drum can be arranged so that its axis of rotation is horizontal. When the drum has a square cross-section and itself there are four electrophotographic plates around it, it can be set up for intermittent rotation by 90 ° each time.

For charging the electrophotographic ones placed around the drum Plates can be any suitable charger, e.g. B. a corona discharger is used will.

A complete image field is exposed at the exposure point. Since the plate stands still at the exposure point, so that the entire image field is simultaneous is exposed, the person operating the device can have any desired control over it perform the exposure process.

After the first plate has been exposed, the drum turns over another 90 ° and releases the exposed plate to the development point, the second., now loaded plate to the exposure point and the third plate is brought to the loading point.

Any suitable developing device can be used to generate electrostatic Powder on. the loaded one and exposed plate to apply and so to create a visible image on it.

In one embodiment there is a groove on each edge of the polygonal Drum attached, which rotates with the drum. One of these gutters will come with filled with an adequate amount of electrostatic powder, optionally with a Carrier material. The arrangement is such that the electrostatic powder in the groove on the front edge of this plate when it comes to the development site, Cascading over the surface of the plate and from the gutter on the leading edge the next disk is caught again. This brings the powder back back to the development center.

Another 90 ° rotation of the drum brings the plates to theirs next posts, and finally the charged, exposed and developed Plate using suitable devices, e.g. B. movable suction heads, too the transfer point moves.

At this point, a piece of transfer material is taken from a roll that is attached to the drum near this point, and is next to the developed plate guided the powder image from the plate onto the transfer material transferred to. It can help to transfer the powder onto the transfer material Any suitable electrostatic device may be used to effect this.

Once the powder image is transferred to the transfer material, this is by means of a suitable device to a fixing device, for. B. an infrared heater, and, if desired, finally to devices who cut the material to the correct size.

When four electrophotographic plates are placed around the drum, d. i.e. if the drum cross-section is square, brings the next rotary motion the drum by 90 ° the plate from the position in which the image was transferred, back to their starting position, d. H. to the charging point.

Before the cycle of the procedure can be repeated, there is one Cleaning of the plate is necessary and a cleaning device must be used for this purpose which is either an electrostatic device for complete discharge the plate or a mechanical device for returning the plate in the old condition, in any case connected to a vacuum cleaning device that Removes all loose parts of the developer powder that are still on the surface of the Stick plate. After the plate is cleaned, it is ready for the process cycle usable again.

The polygonal drum rotates intermittently either by automatic Adjustment, each rotation of the drum being controlled by the function of the machine or by manual control.

Claims (3)

PATENT CLAIMS: 1. Apparatus for making copies by the electrophotographic process, in which the material carrying the electrophotographic layer is moved for the purpose of charging, exposure, development and fixing or transfer to suitable transfer material by means of a transport drum rotatable about its longitudinal axis, characterized in that the Cross section of the transport drum is a rectilinear polygon. 2. Apparatus according to claim 1, characterized by an known devices for intermittent rotation of the drum about the longitudinal axis. 3. Apparatus according to claim 1 and 2, characterized in that the cross section of the Drum is a square.