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CONCRETE PRODUCTS & CAST STONE84 CPI %u2013 Concrete Plant International %u2013 4 | 2025 www.cpi-worldwide.comable. Customized designs such as inscriptions or company logos can also be implemented with a relatively small number of facing concrete compositions. At current ink prices, printing costs range between %u20ac 0.20 and %u20ac 0.50 per square meter, depending on the design.Operating principles of digital printers for highly pigmented inksAll printers used for digital printing with highly pigmented inks operate based on a similar principle called %u201cDrop-onDemand%u201d (DOD). This means that a piezoelectric-controlled print head releases a precisely measured amount of ink as needed. Printing is fundamentally contactless and is applied to the surface to be decorated from a distance of 0.3 to 2 cm, depending on the depth of field.The print heads are integrated in an ink circulation system (see Fig. 4), which consists of heating elements, pumps, and filters. This circulation system is responsible, on the hardware side, for the quality of the print result. Depending on the printer and print head manufacturer, a heating element is installed in the supply tank, the print head circulation loop, and/or on the nozzle plate. This ensures consistent ink viscosity at the specified temperature. The pumping system maintains the sedimentation stability of the highly pigmented inks and influences droplet formation through the meniscus effect. Filters prevent agglomerates and oversized particles from clogging the print head nozzles. When all parameters are perfectly coordinated, the result is a clean and sharp print image.Print headsCurrently, print heads suitable for the application of inorganic pigmented inks are produced by the three most well-known print head manufacturers for highly pigmented inks: Fujifilm Dimatix, Xaar, and Seiko.In terms of their basic functions, all print heads are similar: they have a print width of 7 to 11 cm, a resolution of 360 to 400 dpi, and feature multiple nozzle rows. Depending on the resolution, web speeds of 5 to 35 m/min are achievable. The type of ink ejection, print head control, and ink circulation within the print head vary depending on the manufacturer.The print heads can be used at different angles depending on the product and system manufacturer (see Fig. 5). The material to be printed is shown in blue, and the print heads are depicted in black.Fig. 4: Circulation of a printer.Fig. 5: Different options for attaching print heads.Print headConcrete block