Patent ID: 9643427
Date: 2017-05-09
CPC Classifications: B41J

Claim:
1. A method of an inkjet printer operation comprising a step of printing out image files of a predetermined color depth of b bpc (bits per color), bN, whereat, as the case may be, the color depth signals specified in an image file are converted from the color system F 1 , F 2 , F 3 , for example Red, Green, Blue, applied there into color depth signals of the printing inks D 1 , D 2 , D 3 , etc., for example Cyan, Magenta, Yellow, as well as Black and/or other colors, where applicable, available there so that in the process the resolution used for color depth of b bpc is surviving in the color depth signal referring to the printing color D μ , whereat for one or several, in particular all printing colors D μ , in each case at least two inks T h,μ , T d,μ of the same color D μ , but of varying color intensity are used, namely at least one lighter ink T h,μ of a lighter color intensity J h,μ >0, or even a colorless, brightening ink T f,μ of a brightening, virtual color intensity J f,μ <0 and at least one darker ink T d,μ of a darker color intensity J d,μ , where the following applies: or: with n≧2; and μ=1, 2, 3 . . . ; and whereat on the area assigned one pixel several drops of the same ink T d,μ , T h,μ , T f,μ can be printed, namely maximal (n−1) ink drops of the lighter or colorless ink T h,μ , T f,μ , and maximal (m−1) ink drops of the darker ink T d,μ so that with the darker ink T d,μ m brightness levels can be accomplished, namely 0 . . . (m*J d,μ ), and with the lighter ink T h,μ n brightness levels, namely 0 . . . (n*J h,μ ), what from altogether (n*m) different brightness levels are resulting, namely 0 . . . [(m−1)*J d,μ +(n−1)*J h,μ )], characterized by the fact, that n N, n=2 x , so that the following applies: or: where x N, can be x≧2, for example 2, 3 or 4; then 2 x is in these cases 2 2 =4, or 2 3 =8, or 2 4 =16, and whereat the control signals for a printing unit E h,μ for a lighter or colorless ink T h,μ are derived from the x lower value bits of the color depth signal referenced to the print colors D μ used in such way, that a number of drops of the lighter or colorless ink T h,μ , T f,μ , which is dependent on the value of the binary number in the x lower value bits are shot at frequent intervals in succession, and whereat the control signals for a printing unit E d,μ for the darker ink T d,μ are derived from not more than (b−x) higher value bits of the color depth signal referenced to the print colors D μ , while a number of drops of the darker ink T d,μ corresponding to the binary number in the not more than (b−x) higher value bits are shot at frequent intervals in succession, however time-delayed by a time interval +T, −T corresponding to the physical distance +d, −d of both printing units E h,μ , E d,μ in transport direction of the substrate so that the ink drops of the same ink T d,μ , T h,μ , T f,μ respectively of the same printing color D μ can be printed immediately on top of one another.