From Discworld & Terry Pratchett Wiki
Dozy appears in The Truth, when he comes with Gunilla Goodmountain and Boddony to bring their Movable Type Printing Device to the big city. It is said that dwarfs had found out how to turn lead into gold. Using the press the hoped to do just that.
Dozy accompanied Boddony and Sacharissa when they used to underground streets of buried Ankh-Morpork to undermine the rival printing firm and paper the Ankh-Morpork Inquirer. Dozy commented with delight on the size of the rats that were found underground, but was convinced to skip lunch, and focus on their mission. It proved successful, and they were able to break into the basement of the Inquirer and remove their lead writer, Cut-Me-Own-Throat Dibbler, and bring him back to the Times office to 'give him a stern talking to'.