Man Roland Druckmaschinen Ag

Man Roland Druckmaschinen

Rolf Braun

Joachim Muller

Alfred Dorn

Gerd Steiner

Rainer Otterbach

Erhard Schubert

Rudi Weniger

Ralf Hofmann

A method for regulating ink distribution in a printing machine is disclosed. In accordance with the disclosed method, a basic ink quantity and a compensating ink film thickness are determined for a printing plate to be loaded into the printing machine. All of the inking rollers of the printing machine are fed ink until the ink thickness on each roller is substantially equal to the compensating ink thickness. A steady state ink distribution within the printing machine will be attained relatively quickly, thereby minimizing print waste and time required to attain steady state.

Method for regulating ink distribution in a printing machine

A system and method for determining register differences between the images making up a multi-color printed image. A color video camera with macro optics scans at least a part of the image. The video image is processed to derive a plurality of single-color images, information from which is stored in respective single color memories. A register-checking location is selected having a contour in the printed image which has at least two superimposed single colors. The information in the color memories is processed to determine separation contours for the respective colors. Offsets are determined for the contours in the respective image memories as a measure of register differences between the images.

Method and apparatus for determining register differences from a

Method and apparatus for scanning an ink test strip printed on a sheet, the sheet being positioned on a table traversed in two directions by a scanning head. The table includes guide means including a bar for positioning the sheet in a first dimension and an index mark for positioning the sheet and its associated test strip in a second dimension. The scanning head indexes to the index mark which physically establishes a first coordinate for the test strip. Thereupon, the scanning head indexes in a second direction to automatically locate the test strip based on the size of the test strip as sensed by the densitometric sensing device associated with the scanning head. Having located the second coordinate Y.sub.s for the initial test patch of the test strip, the system then initiates the scan along the test strip to measure the optical density of each test patch relating to each printed zone on the sheet.

Densitometric sensing device for use in printing presses

An ink fountain of the type in which ink is metered from nozzles located in respective zonal positions. The nozzles have narrow axially extending openings in general alignment with one another closely side by side. A tank is provided adjacent the fountain roller, with the nozzles being in the form of slots at the bottom of the tank, the tank being sealed and connected to a source of viscous ink under predetermined pressure. Reciprocable slides are arranged side by side interposed between the nozzles and the surface of the fountain roller, each slide having a reference position for normally blocking off ink flow from the associated nozzle and being retractable to open the nozzle. A solenoid is connected to each of the slides for forcibly and temporarily retracting the slide from its reference blocking position. Each solenoid has a biasing spring for restoring the slide to its reference blocking position. An individually adjustable timing device is controllingly connected to each solenoid for cyclically energizing it for pre-set intervals of time which correspond to the ink requirement in the respective zonal position. The tank in the preferred embodiment is supplied with ink through a supply line fed by a pump from an open reservoir.

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Offenbach am Main, Germany

Rolf Braun