Inkjet printers are remarkable devices, capable of laying down inks with extreme precision.
Today’s invention is to apply this to the creation of adhesive labels.
Imagine a printer which is creating a page of eg address labels. On the opposite side from the text, an extra print head sprays adhesive onto the paper.
The spray could generate a pattern which used just enough glue to effectively attach the labels. It could be made coloured, so that the sticky areas could be avoided when handling the paper.
(This would also allow envelopes to be made from a flat sheet of paper and then folded so that the pre-glued edges stuck together. Or, apply the glue to a roll of paper to make masking tape).