As is well known, expressions like "at the printers" or "to the cleaners" can be equivalent to "at the printer's shop" or "to the cleaner's shop" respectively. But if this is so, these expressions could be construed with a plural or a singular verb. So my question is, which one of the followings is grammatical—A, B, or both?
A. The printers is near the hospital.
B. The printers are near the hospital.
It should be the printer's is, and it is singular, as it refers to a shop, as you say, not to people plural. The 's is a possessive s, with an apostrophe. Whenever you really mean plural printers, spelled as such, use the plural, printers are. It's really that simple!
I'm not sure about the equivalence between "at the printers" and "at the printer's (shop)". When spoken, the two sentences can surely overlap, as you cannot distinguish between them from their sound.
However, from a grammatical point of view, a singular subject requires a singular verb form. So, if your meaning is "the printer's (shop)", then the sentence will be correctly completed by the verb is; if on the contrary "the printers" are actually more than one, then you can use the verb form are.
Ceberus is absolutely correct. If you are talking about the printer's as a shop, you should use is. However, a lot of native english speakers are lazy, and will simply think: "printers has got an 's', so it must be plural" and will say the printers are ... in either context.
Also, depending on whether the shop belongs to just one printer (the printer's) or a bunch of them (the printers') you might have to move the apostrophe to the other side of the 's'. Either way, if it is only one shop (implicit or otherwise), you use is
