Most PCBs have a component legend to show which component goes where this is known as Silkscreen or Legend.

Today we use ink-jet printers to image the legends direct from the board digital data.  Like a conventional paper printer the ink-jet printer sprays minute droplets of ink onto the panel to generate the image.  If a legend is needed on the second side the ink is tack-dried on a conveyorised heater and the printing process is repeated.  Ink-jet printing needs no set-up.  Previously we lost time preparing and cleaning silk-screens for each legend printing.  That is why the legend is often called the silk-screen.

Now we finally cure both the epoxy ink soldermask and the legend.  Once this took 90 minutes in a batch oven.  Now it takes less than 10 minutes using a 5 stage conveyorised oven.

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