Rubber Rollers
The invention relates to an inking roller for an inking unit of an offset printing press wherein the inking roller includes a number of zones arranged in the direction of the axis of rotation and at least one ink reservoir in the interior of the inking roller. In each of the number of zones, the at least one ink reservoir is connected to at least one ink exit in the circumferential surface of the inking roller. In inking units of offset printing presses, ink is frequently supplied from an ink fountain or ink reservoir to a group of inking unit rollers by means of an ink fountain roller and ink metering devices arranged along the axis of rotation of the ink fountain roller. Different amounts of ink are generally supplied to different zones as governed by the individual ink metering devices allocated to the individual zones and as selected in accordance with the subject to be printed. Ink metering devices, in particular those equipped with a flap or a blade, are difficult to control or regulate.The ink film needs to be calibrated with high precision, and yet manufacturing tolerances result in a certain play and thus in settings that are difficult to reproduce after a certain time (in particular the zero setting), in particular if the ink metering device must be dismounted for maintenance work. In addition, the cost of such an ink, metering element is considerable. An inking roller according to the invention for an inking unit of an offset printing press has a number of zones arranged in the direction of the axis of rotation of the inking roller and at least one ink reservoir in the interior of the inking roller. The at least one ink reservoir in each of the number of zones is connected to at least one ink exit in the circumferential surface of the inking roller in such a way that the ink present in the ink reservoir can get to the circumferential surface of the inking roller. At least one pumping element for conveying ink from the ink reservoir to the circumferential surface is assigned to each zone and located in each zone in the interior of the inking roller. The inking unit according to the invention represents a simple system that has only few components and does not cost much. Advantageously, the mounting of the inking roller requires less mechanical precision than in common ink metering devices. The hardness of the Inking rollers should be maintained in between 28 shore A to maximum 32 Shore A with the tolerance of ± 5 shore A. Most of the inks are oil based so the inking rubber should be oil friendly.
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