Dr. Ing. Rudolf Hell Gmbh

Hell Gravure Systems Gmbh

Ing. Rudolf Hell Gmbh

Dr. Ing. Rudolf Hill Gmbh

Siegfried Beisswenger

Wolfgang Boppel

Dieter Grieger

Heinz Taudt

Michael Biewer

Maximilian Rid

An idle distance of an engraving stylus for engraving a rotogravure printing cylinder is set from the cylinder surface of the rotogravure printing cylinder by use of a sliding element that is provided for the guidance of the engraving stylus connected to the sliding element along the cylinder surface during engraving. The setting of the idle distance is undertaken relative to a reference surface that is indicative of the cylinder surface.

Method and apparatus for setting the idle distance of an engraving stylus from the cylinder surface of a rotogravure printing cylinder

In a method to produce a printing form for rotogravure, in particular for heliorotogravure, a surface of the formis provided with a wear-resistant layer and the surface is provided with cups. Furthermore, a printing form is provided whereby the surface of the printing form comprises a wear-resistant layer in which the cups, with regard to their depth, are at least partially provided therein. The printing form may be used in a printing device for heliorotogravure.

Method to produce a printing form for rotogravure, printing form for rotogravure and their use

In a method for operating an engraving member in an electronic engraving machine to engrave printing forms, especially printing cylinders for intaglio printing, a stylus of the engraving member is controlled by an engraving signal and engraves a sequence of cups arranged in a gravure screen in the rotating printing cylinder. The engraving signal is formed by superimposing the image signal representing the tone gradations to be engraved. In order to obtain good quality engraving, the engraving member is heated to a temperature that is close to operating temperature before engraving starts and/or during an interruption of engraving. For this purpose, the engraving member is driven with a periodic signal whose frequency is preferably located inside the ultrasonic range in order to avoid noise disturbances.

Method for the operating an engraving member

An electron beam generator designed for engraving surfaces of printing form cylinders is switched to microscope operation during engraving pauses in order to make engraved cups visible immediately and without additional auxiliary equipment. During microscope operation, deflection parameters and an intensity of an electron beam produced by the electron beam generator are changed for appropriate scanning. An image signal is acquired by detecting secondary electrons generated by the beam interacting with the cups in the printing form surface.

Method for checking printing form surfaces engraved by means of an

A method for the topically precise subsequent-engraving of printing cylinders wherein special marks are engraved in the cylinder and evaluated. The marks are engraved in the form of cups forming a cup track. The cups serve as reference marks for an axial feed and start of the subsequent-engraving in a circumferential direction. After the printing cylinder has been mounted in an engraving machine for subsequent-engraving, the cylinder is placed in rotation and the scanner is moved over the previously engraved cup track axially. A maximum of the signals received from the scanner is identified and a location of the maximum in the cup track is retained as a reference value for the axial feed during the following engraving. A cup track is provided with at least one defined gap that is free of cups. A first cup following the gap is identified by means of the scanner and evaluated as a reference location for a start of engraving in the circumferential direction for the following subsequent-engraving.

Method for the topically precise subsequent engraving of printing

High stability electron beam generator for processing material

In printing form production with electron beams, the imaging scale of the electron source on the source of the printing form is modulated gradation-dependent for engraving different cup geometries. The power density distribution in the effective point of the electron beam can then be approximately rectangular for all gradations. In particular, engraving the small cups, which was hitherto a vertical factor, is thus stable.

Electron beam engraving method and device for execution

An electron beam generating system provides a high degree of steadiness of the beam current and comprises a heated cathode, an auxiliary electrode lying at a more negative potential than the cathode, and a transpierced anode. A diaphragm surrounding the beam and connected to a precision resistor is further provided at that side of the auxiliary electrode facing away from the cathode. A portion of the beam current influenced by the control electrode is blanked out by the diaphragm. The precision resistor is connected as an actual value generator to a regulator which is connected to a reference voltage, the output of the regulator influencing the potential of the control electrode over a final control element for the purpose of maintaining the beam current measured by the diaphragm constant.

Highly-steady beam generating for charged particles

Apparatus and method for engraving with an electron beam such that depressions of different sizes can be generated in the surface of a workpiece and the different sizes of depressions are produced by an electron beam and wherein during periods when depressions are not to be formed the electron beam remains on but is defocused so that it does not form depressions. A modification of the invention provides that at times when the beam is not being used to cut depressions that it is pulsed wherein the short pulses of the beam which engage the work surface do not do any cutting.

Apparatus and method for engraving with an electron beam

An orifice for coupling a highly-evacuated electron beam gun to a rotating print form cylinder for engraving is provided such that the gun has a rigid cover with an opening for the electron beam at its end facing the print form cylinder and a flexible band is arranged at the cover which partially surrounds the print form cylinder. The band is pivoted at the cover and at least one of the pivot points is elastically designed and pivoting occurs with the aid of springs which are adjustable with respect to the spring force.

Orifice for coupling an electron beam gun to print form cylinders

An electron-optical lens arrangement for electron beam apparatus having a static and a dynamic focussing lens system, in which the dynamic focussing lens system is situated inside the static focussing lens system.

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Preetz, Germany

Siegfried Beisswenger