Man Roland Druckmaschinen Ag

Roland Offsetmaschinenfabrik Faber & Schleicher Ag

Siegfried Schuhmann

Bert Cappel

Alfred Dorn

Peter Schramm

Gerd Steiner

Gunther Schniggenfittig

Peter Mayer

Edgar F Schoneberger

Helmut Kerber

Klaus Wolf

Jurgen Rehder

Oded Zingher

An apparatus to obtain ink density data by scanning color measurement strips on a printed sheet has a densitometer mounted on a digitally-driven X,Y positioning mechanism, an optical sensor for detecting the position and orientation of the sheet with respect to the X,Y positioning mechanism, and a numerical computer for transforming the sheet coordinates of the color measurement strips to the X,Y coordinates of the X,Y positioning mechanism. Thus, the numerical computer can automatically position the densitometer to scan the color measurement strips. In a first embodiment, optical sensor arrays determine the position and orientation of the test sheet with respect to the X,Y positioning mechanism. In a second embodiment, the densitometer itself scans the edge portions of the test sheet to determine the position and orientation of the test sheet. The operator has the option of using sheet coordinates of the color measurement strips obtained from non-volatile storage, from a recording medium such as magnetic tape or disk, from direct operator entry from a keyboard, or from the sighting of the measurement strips on the test sheet arbitrarily positioned and oriented with respect to the X,Y positioning mechanism.

Apparatus for determining and evaluating color measurement strips on a

A machine for scanning printing plates to determine the ratio of 'printing' to 'non-printing' area for pre-adjustment of the ink dosing elements of a printing machine has an array of electronic photo-sensors, each sensor being disposed in a channel having low-reflection chambers which permit sharp delimination of resolution elements on the printing plate and ensure high definition scanning of different types of printing plates under practical conditions. Preferably the diaphragms dividing the channel into chambers have greater spacing at greater distances from the element sensed on the printing plate. To accommodate printing plates of different materials, means are provided for selecting the wave length of the light source. To prevent measurement error due to changes in the distance from the printing plate to the light source and sensor array, the photosensor array is preferably directed or aimed 60.degree. to 45.degree. with respect to the normal vector of the printing plate, and the light source is in the same quadrant as the photo-sensor array at an angle of 0.degree. to 45.degree. with respect to the normal vector. Automatic calibration, automatic printing plate size determination, automatic sensing of identification information engraved on the printing plate, and a stairstep scan to increase the scanning rate are provided by suitable procedures executed by a microcomputer controlling the scanning process and analyzing, adjusting, and interpreting data received from the sensor array.

Arrangement for scanning printing plates

An ink metering system for letterpress and offset printing machines is provided in which the duct roller, the ink vibrator discs and the transfer roller have a low circumferential speed and wherein the ink is accelerated by suitable vibrator devices to higher speeds corresponding to the circumferential speed of the plate cylinder. The ink vibrator discs are controlled under defined conditions by various lever systems in order that the ink may be transferred controllably and in optimum manner without any empty gaps. The ink vibrator discs can also be readily removed and fitted for repair and cleaning purposes.

Ink metering system in letterpress and offset printing machines

An ink fountain for a printing press has a temperature-responsive element for compensating the adjustment of the spacing between the blade and the fountain roller to keep the thickness of the ink film fed by the blade substantially constant even under extreme temperature variations. The sub-frame of the ink fountain is pivotally mounted to the main frame of the printing press about a pivot axis generally parallel to the axis of the fountain roller, and the pivot angle is a function of the thermal expansion of the temperature-responsive element. In one preferred embodiment, the temperature-responsive element is elongated, received in a guide fixed to the sub-frame, and has a free end bearing against the bearing bushing of the fountain roller. In another embodiment, the temperature-responsive element is a side wall of the ink trough or is a plate parallel to the side wall of the ink trough, and rollers are journaled to the temperature-responsive element and bear against the surface of the fountain roller. In either embodiment, the temperature-responsive element is pre-stressed by a pull rod tending to pivot the sub-frame so that the temperature-responsive element bears against the sub-frame and the main frame.

Ink fountain having temperature responsive element

An ink fountain including a frame defining a horizontal slot adjacent the fountain roller. Arranged side by side in the slot is a metering assembly in the form of a series of flat slides each having a cam assembly at its rear end for adjusting the position of the slide with respect to the fountain roller thereby to meter ink in predetermined thickness in respective zones. Each slide is formed of a body having secured thereto a rectangular tip portion formed of resilient plastic. The tip portion of each slide has embedded in it a blade of wear resistant spring metal, the blade being coextensive with the width of the slide and so oriented as to present a flat face to the fountain roller defining, with the fountain roller, a sharply acute cusp. The rectangular tip portion of each slide is relieved in the region just behind the spring metal blade to permit the blade to flex broadwise resiliently and accommodatingly when the slide is advanced to bring the edge of the blade against the surface of the fountain roller thereby to achieve a seal between the blade and the fountain roller with only limited reaction force being exerted between them.

Arrangement for metering the ink quantity in inking units on printing

An automatic ink feed control for a printing machine. Several ink-dosing elements are arranged across the width of the printing machine for dosing the application of ink to a printing plate, and these ink-dosing elements are individually adjustable by an adjusting device. The ink density of several control areas on the printed material is measured by a scanning measuring device, and a computer control compares these measured ink densities to desired ink densities in order to effect control of the adjustment of the ink-dosing elements by the adjusting device.

Means for the control and regulation of the printing process on printing

Apparatus for facilitating peripheral adjustment of a printing plate on a printing cylinder of a multicolor printing press in the form of an optical viewing device having magnifying optics including a single eye piece and two objectives. The objectives are spaced for simultaneous viewing of a peripheral reference mark at the end of the cylinder and an index mark on the plate which is positionally related to the image thereon. The optical viewing device has a screen including an optical reference, with the reference and index marks being superimposable thereon in the same field of view. In one form of the invention a calibrated scale is provided on the screen for direct measurement of the disparity in peripheral register between the two marks. In another form of the invention the bracket which supports the viewing device has an associated calibrated micrometer screw for bodily movement of the viewing device between the two marks and with the change in micrometer reading providing a measure of the amount that the plate must be moved to achieve peripheral register.

Device for adjusting printing plates on the plate cylinder of printing

An ink fountain having a metering assembly in the form of a series of rectangularly shaped slides fitted into a horizontal slot in a frame with only the presented front ends of the slides being exposed and abutting the fountain roller. The slides are arranged side by side in coplanar relation with their lateral edges lying closely adjacent one another. Notches are formed in the lateral edges of the slides adjacent the front ends thereof, with the notches being occupied by slightly oversized buttons of resilient sealing material. The metering assembly is held captive at its ends between two vertical end plates which apply inward squeezing pressure to the metering assembly so as to compress the resilient buttons uniformly to bring the lateral edges of the slides into snug sliding relation to prevent leakage of ink between them and for the purpose of distributing any cumulative tolerance error equally between all of the slides in the series. Means are provided for confining the rear ends of the slides so that all the slides of the series are oriented precisely parallel to one another. Each of the slides has provision at its rear end for longitudinal adjustment in the form of an eccentric mechanism having a shallow throw. Each of the slides has a shank portion which is laterally relieved over the major portion of the length thereof so that the lateral edges of adjacent slides are in engagement only at the front and rear ends.

Ink metering assembly for printing press

A delivery arrangement including a conveyor and take-off mechanism for delivering a series of printed sheets onto a pile in which nozzles are provided distributed along the width of a sheet, for directing a jet of air to the underside in a direction opposite the sheet movement. A guide plate spaced under the sheet and extending upstream from the nozzles serves to confine the jet. Formed on the surface of the guide plate are a plurality of upraised islands, spaced from one another over the area of the guide plate, the islands presenting plateau surfaces at approximately the same elevation above the guide plate. Consequently, when a sheet is sucked downwardly by the jet of air it engages the plateau surfaces in light frictional engagement to apply frictional drag to the body of the sheet. The source of pressurized air for the nozzles includes means for automatically varying the pressure, and hence the frictional drag, in accordance with the speed of the press. In a preferred embodiment the plateau surfaces, which are spaced both laterally and longitudinally of the guide plate, occupy less than half of the total area of the guide plate and at least a portion of the guide plate is formed with a gradual curvature in a direction downwardly away from the sheet.

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Offenbach am Main, Germany

Siegfried Schuhmann