Solid ink printers, also known as phase-change printers, are a type of thermal transfer printer.They use solid sticks of CMYK-coloured ink, similar in consistency to candle wax, which are melted and fed into a piezo crystal operated print-head.
The printhead sprays the ink on a rotating, oil coated drum.The paper then passes over the print drum, at which time the image is immediately transferred, or transfixed, to the page.
Also, some users complain that the resulting prints are difficult to write on, as the wax tends to repel inks from pens, and are difficult to feed through automatic document feeders, but these traits have been significantly reduced in later models.
In addition, this type of printer is only available from one manufacturer, Xerox, manufactured as part of their Xerox Phaser office printer line.
Previously, solid ink printers were manufactured by Tektronix, but Tek sold the printing business to Xerox in 2001.Źródło: https://en.wikipedia.org/wiki/Printer_(computing)
They are ordered wholesale and also consumed in bulk.For each order, the production costs are optimized, and the appropriate technique and type of printing is selected. Graphic designers, DTP operators and printers deal with this. They are responsible for the quality of the printout and as soon as something is wrong they are the first to be targeted by the dissatisfied boss.
Their work is quite hard and I have to admit that you have to really have a fuss to do it.