chain printer vs impact printer

chain printer and impact printer both are nouns.

Word	Noun	Adjective	Verb	Adverb
chain printer	Yes	No	No	No
impact printer	Yes	No	No	No

As nouns, impact printer is a hypernym of chain printer; that is, impact printer is a word with a broader meaning than chain printer:

chain printer: an impact printer that carries the type slugs by links of a revolving chain
impact printer: a printer that prints by mechanical impacts

chain printer (noun)	impact printer (noun)
an impact printer that carries the type slugs by links of a revolving chain	a printer that prints by mechanical impacts