Okay kiddo, so a letter-quality printer is a type of printer that was used a long time ago before the cool printers we have now. It was really special because it could print words and letters that looked just like how they did when someone wrote them with a pen or pencil. Other printers at that time could only make really simple letters that didn't look like the real thing.
So how did the letter-quality printer do this? Well, it had a really special way of printing. It would have a little metal ball that had all the letters and symbols on it. And when you wanted to print something, the printer would move that ball around really fast to the right spot, and then press it onto the paper to make a perfect letter or symbol.
The coolest thing about these printers was that they could print on a special type of paper called "carbon paper". This was a paper with special ink on it that could help make copies of letters. So, if you wanted to make five copies of a letter, you could put a sheet of carbon paper under the letter you were typing and it would transfer the letter onto five more sheets of paper at the same time!
So, now you know all about letter-quality printers! They were special printers used a long time ago that could print letters that looked just like real handwriting and they could make copies too!