I wonder what the difference between the and that in this context is:
A: Hey, I've heard we have a new printer.
B: Really? Let's print the documents on the/that new printer then.
I think the two real choices are:
Both the above seem pretty much identical in meaning to me. The second can only be used following a mention of a specific printer, or accompanied by physically indicating a printer. The first can be used in those contexts but doesn't require any context of that sort.
Only if there were several new printers and someone had previously referred specifically to one of them (e.g. "One of the new printers is fast!") would I write or say:
Short Version: Articles (the) help specify certain characteristics of nouns (definiteness, number) Whereas demonstratives are mainly reserved for selection (that one) and spatial deixis:
In this particular case, the meaning of the sentence changes very little. However, in English, there are subtleties in the function of seemingly interchangeable words.
The is a definite article. It functions only as an adjective and has no tense. In this case, it's used to identify a primary printer. Most people hear the and tend to lean towards "singular, the main one" even if the following noun is plural. In this example, the is used to round multiple nouns into a single unit:
The performs a function that can only be accomplished by an alternative demonstrative:
Demonstratives such as this, that, those, and these COULD perform the same job as an article, but due to all the variations, they are more flexible than simple articles:
In that sentence, those performs the same job that the might do. but if you take out the word sandwiches, it becomes a pronoun with sandwiches as its antecedent.
These various words all seem more or less interchangeable, but one of the most important functions of demonstratives is something called spatial deixis, where the message can change based on the speaker/reader's physical surroundings. Similar to words like there and here, they are a little more descriptive (therefore more effective) than articles. This difference is practically negligible until multiples are involved and such details are needed to preserve the clarity of the sentence:
In these examples, if we had used definite articles, they would have looked like this:
The sentences are now unclear because we lack certain details that definite articles can't deliver. Keep that in mind when choosing a word.
Sorry for the lengthy response. Demonstratives are really tricky since they often have little effect on the meaning of the sentence. The only thing changing is specificity and details.