Dosing system for inking up rollers in a printing machine

#The invention concerns a metering system for the inking of rollers in a printing machine, with at least one roller train leading to a plate or form cylinder, wherein the rollers can be inked by means of ink or lacquer from a storage container, according to the preamble of the main claim. The invention can preferably be used in an inking unit of a printing machine with a rotating roller arranged between an ink fountain roller and a subsequent inking unit roller, particularly in a film or vibrating inking unit.

#A printing machine with a vibrating inking unit is known from DE 37 06 602 A1. Here, an ink fountain roller is in functional connection with an ink fountain with a metering system for the printing ink, as is known from, e.g., DE 27 11 553 A1. For printing machines with a vibrating inking unit, the printing ink is periodically removed in strips from an ink fountain roller by back and forth pendulate motion of an ink vibrating roller and fed to an inking unit roller of the subsequent roller train. Limited by the different rotational speeds of the ink fountain roller and the inking unit roller, vibrating inking units have the problem that the inking vibrating roller is delayed or accelerated with each strike (contact) to the ink fountain roller or the inking unit roller. With this striking or lifting of the vibrating roller, there is nonuniform ink guidance during the ink transport of the printing ink, in connection with an up-and-down ink separation in the contact zone of the rollers, also on the ink fountain roller or on the inking unit roller, which has a quality-reducing effect on the printing. Due to the ink separation of the printing inks between the ink fountain roller and the ink vibrating roller, as well as between the ink vibrating roller and the subsequent inking unit roller, uneven surface structures are formed for the remaining ink on the roller surfaces, which leads to reduced quality on the printing material.

#From DE 38 04 204 A1, an inking unit of a printing machine with a film roller is known. Such a film roller is designed for the ink transport across a film gap (first contact zone) in contact with the ink fountain roller as well as in a second contact zone with the subsequent inking unit roller, of the subsequent roller train, so that a continuous ink transport of printing ink between the ink fountain roller and the inking unit roller of the roller train can be realized in the inking unit. In addition, an intermediate roller is arranged in contact with the film roller, wherein a doctor blade roller is arranged after this intermediate roller. In contact with the doctor blade roller there is an adjustable doctor blade, and the doctor blade can be set or adjusted depending on the subject or at intervals on the doctor blade roller. The printing ink removed by the doctor blade roller is then led back into the ink fountain. This film inking unit is used for minimizing the minimum ink amount by removing a portion of ink from an inking unit and is relatively expensive due to the additional use of rollers (intermediate roller, doctor blade roller). In the contact zones of the ink fountain roller and film roller and film roller and subsequent inking unit roller, there occurs, analogous to the described vibrating inking unit, an ink separation of the printing ink per contact zone, so that also for film inking units, uneven surface structures are formed for the ink on the roller surfaces, which leads to reduced printing quality on the printing material.

#The invention is to be explained in more detail with an embodiment. Here, shown schematically are:

#FIG. 1, the arrangement of a metering system for inking an inking unit,

#FIG. 2, an ink metering system in functional connection with an ink fountain roller,

#The offset printing press of a sheet-fed rotational printing machine essentially consists of an inking unit with an ink fountain roller 1 in functional connection with an ink fountain 9 with an ink metering system 8, e.g., ink valves, furthermore a vibrating roller 2 or a film roller 6 and an inking unit roller 3 configured as a first ink friction roller (can be driven with rotating and transverse axial motion) of a subsequent roller train 7. This roller train 7 leads to the plate cylinder (or form cylinder) and has, in a known way, a plurality of rollers, of which, e.g., the second ink friction roller 5 (can be driven with rotating and transverse, axial motion) is designed with intermediate transfer rollers 4 (FIG. 1).

#A plating device 12 is assigned to at least one roller (1-6) of the inking unit adjacent to its outer surface after a contact zone 10, where a pulling off or separation of ink occurs, and this plating device can be set, and preferably adjusted, to the outer surface of the roller (1-6). The plating device 12 thus extends essentially parallel across a full roller width 15.

#Preferably, the plating device 12 can be set by means of a force F to the outer surface of the corresponding roller (roller 1-6). By means of the plating device 12, preferably a uniform surface pressure can be applied across the roller width 15 (roller 1-6) on the ink or remaining ink, alternatively on the outer surface of the roller 1-6 guiding the lacquer.