BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing inking variables as a function of a time during changeover from a first ink amount metering to a second ink amount metering without temporary increased adjustment of the ink metering element, in an exemplary parameter combination;
FIG. 2 is a diagram showing inking variables as a function of the time during changeover from a first ink amount metering to a second ink amount metering with temporary increased adjustment of the ink metering element according to the prior art for the parameter combination which is shown in FIG. 1; and
FIG. 3 is a diagram showing inking variables as a function of the time during changeover from a first ink amount metering to a second ink amount metering with temporary increased adjustment according to the invention of the ink metering element for the parameter combination which is shown in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in detail to the figures of the drawings, in which only inking variables that result from the action of an ink metering element will be considered in order to simplify the illustration without limiting the reference to zonal inking units according to the invention which has already been described, and first, particularly, to FIG. 1 thereof, there is seen an exemplary parameter combination shown in a diagram of inking variables plotted as a function of time during changeover from a first ink amount metering to a second ink amount metering without temporary increased adjustment of the ink metering element. A desired inking 10, a calculated steady-state end value, is to be achieved by the changeover. To this end, an ink metering element is adjusted from a first ink amount metering 14 to a second ink amount metering 16 at a defined instant. A current actual inking 12 has a temporal profile such that it converges monotonously with the desired or setpoint value 10 in a defined reaction time of the inking unit. Sufficient convergence is achieved in this example at approximately three time units.
FIG. 2 is a diagram of inking variables as a function of the time during changeover from a first ink amount metering to a second ink amount metering with temporary increased adjustment of the ink metering element according to the prior art for the parameter combination which is shown in FIG. 1. In order to influence the reaction time of the inking unit, a temporary increased adjustment 18 is carried out according to the prior art after the defined instant of the adjustment from the first ink amount metering 14 until another defined instant, at which an adjustment is made to the second ink amount metering 16. According to the prior art, the magnitude and the sign of the temporary adjustment are based on the initial and end values of the ink amount metering and the direction of the change, that is to say in that case a reduction from a greater first ink amount metering 14 to a smaller second ink amount metering 16. In that parameter combination, the temporal profile of the current actual inking 12 experiences a first kink at the defined instant and a second kink at the other defined instant. The temporary increased adjustment 18 according to the prior art is counterproductive in that parameter combination which is shown: the adjustment 18 leads the current actual inking 12 away from the desired inking 10 which is to be achieved, and the current actual inking 12 only converges constantly and monotonously with the desired inking 10 after the adjustment to the second ink amount metering 14 has taken place. Sufficient convergence is achieved in that example only at approximately four time units, that is to say at an instant which is after that without the increased adjustment 18.
Finally, FIG. 3 shows a diagram of inking variables as a function of the time during changeover from a first ink amount metering 14 to a second ink amount metering 16 with temporary increased adjustment according to the invention of the ink metering element to a third ink amount metering 20 for the parameter combination which is shown in FIG. 1. In order to shorten the reaction time of the inking unit, the temporary third ink amount metering 20 is performed according to the invention after the defined instant of the adjustment from the first ink amount metering 14 until another defined instant, at which an adjustment is made to the second ink amount metering 16. According to the invention, the magnitude and the sign of the temporary adjustment to the third ink amount metering 20 are based on the current actual inking 12 and the desired inking 10. In the case which is shown specifically, the direction of the change to the third ink amount metering 20 is positive, since the current actual inking 12 lies below the desired inking 10 which is to be achieved. However, the basis for the magnitude of this temporary adjustment is not the measured non-steady-state actual inking 22 at the defined instant, but a corrected value 24 which represents a value for the actual inking 12 that is adjusted for the dead time. The corrected value 24 is achieved later as the measured value for the non-steady-state actual inking 12. In this parameter combination, the temporal profile of the current actual inking 12 extends from the instant, at which the corrected value 24 is achieved, toward the desired inking 10 in a steeper monotonous manner and therefore more rapidly. The temporary increased adjustment according to the invention to the third ink amount metering 20 is effectively active in this parameter combination which is shown: the current actual inking 12 converges more rapidly in a continuous and monotonous manner with the desired inking 10. As an advantageous consequence, sufficient convergence is already achieved in this example after approximately three quarters of a time unit, that is to say at an instant which lies considerably before that without increased adjustment 18 and with increased adjustment 18 according to the prior art. While the ink amount meterings are not a good measure of the actual ink amount conditions in the inking unit, an acceleration of the reaction of the inking unit and the convergence of the inking unit setting to a desired inking can be achieved according to the invention on the basis of the current inking 12.
In one advantageous embodiment, according to the invention, the method for setting the inking zone openings is used for continuous printing in an offset printing press having a zonal inking unit and a control computer. The current actual ink layer measured value is detected and fed to the control computer. The current actual ink layer measured value is corrected, and the ink zone opening for the desired layer end value is calculated. An increasing factor as a function of the desired layer end value and the current corrected actual ink layer measured value is calculated. The ink zone openings are loaded with the increasing factor for a defined number of printed sheets.
According to the invention, in one preferred embodiment, the current, non-steady-state actual layer thickness/actual density is used in the calculation of an ink zone adjustment for an increased adjustment. The values are corrected in accordance with the system dead time. In other words, consideration of the system dead time including measured dead time is taken into consideration during the calculation of the dynamic ink zone adjustment. An increased adjustment, on which the overdriving of the ink zone adjustment is based, is calculated from corrected actual and setpoint values. The end value of the ink zone adjustment is based on the ink regulation. The dynamic ink zone adjustment is separate from the calculated static ink zone adjustment.
Patent Application
20070283830
