Abstract: An ink jet printing method for performing printing onto a printing medium with the use of both of a colored ink ejected from an ink jet head and a printing property improving liquid to be applied to the printing medium for improving a printing property for an ink jet printing apparatus, having the steps of: at least one time or more printing a first colored ink on the printing medium, at least one time or more applying the printing property improving liquid onto a region printed with the colored ink, and at least one time or more printing a second colored ink on a region where the printing property improving liquid is applied.

Abstract: When printing is performed by ejecting respective inks of black and cyan and a processing liquid, an OR data and an AND data are derived from an extracted data for the processing liquid derived from an ejection data of the black ink and an extracted data for the processing liquid derived from an ejection data for the cyan ink. An OR data of the OR data derived from the extracted data and data derived by shifting the AND data for one pixel, is taken as an ejection data for the processing liquid. By this, for the pixel, on which black and cyan are ejected in overlapping manner as represented by the AND data, the processing liquid is further ejected on a pixel adjacent thereto. Thus, the processing liquid in an amount corresponding to an ink ejection amount can be ejected to provide sufficient water-resistance.

Abstract: In an ink jet head having an ink discharge head for discharging an ink, and a liquid discharge head for discharging a print improving liquid given to a printing medium for improving printability in ink jet printing, the liquid discharge head 2002 is disposed to be sandwiched between colored discharge heads 2001 and 2003 for discharging at least one set of colored inks with respect to a scanning direction. This provides an ink jet head for optimally utilizing a pre-feed technique and/or a follow feed technique in ink jet printing.

Abstract: Using a recording head with 8 nozzles, and feeding paper or recording medium by an amount equal to 2 nozzles at each recording scan, recording is made with respect to first and second rasters in a first recording scan by #7 and #8 nozzles. At this moment, the #7 nozzle has a SMS printing rate of 1/3, and the #8 nozzle has a printing rate of 1/4. Initial values of a context memory are both 0. After the paper is fed by 2 nozzle distance, in a second recording scan, first--fourth rasters are recorded by #5-#8 nozzles. Rasters to be recorded are increased by 2 at every paper feed by 2 nozzle distance, and after 8 rasters, the rasters to be recorded are decreased by 2. Since the printing rate of the odd number nozzle is larger than that of the even number nozzle, an odd numbered raster is recorded partly two times by the odd number nozzle, thereby making emphasis printing uniformly over the entire image.