When it comes to printed books, what's the difference between a printer and a publisher?
If you sign a deal with a publisher, does the publisher print the book?
If you sign a deal with a publisher, who owns the rights to the book - the author or the publisher?
If you, the author, sign a deal with a printer, who owns the rights to the book - the author or the printer?
Off the top of my head, a printer is responsible for producing physical copies of your book and providing them to you.
A publisher is going to contract with a printer to get the physical copies so you don't have to; they would also handle things like advertising the book to drive sales, maybe distributing the physical books to sales channels, helping book the author for appearances and signings and readings etc.
It's simple. When you do a deal with a publisher the rights you retain and the rights that you get are set forth in the contract. Read it, understand it and spend the small amount it will cost to have a lawyer explain it to you.
Aside from whatever rights may be specified in your contract, the owner of the ISBN is the publisher and is listed as such in metadata and wherever the publisher is recorded, even if you put your own name as publisher on the copyright page. Lulu, for example, is the publisher of your book if you use their free ISBN.
Joe Bondi Beach's books are "published" by Clearing Rain Press, an entity that exists in the twilight zone somewhere inside Joe's head, but the actual listed publisher is Lulu Press.
Lulu explains clearly what rights (including copyright) you retain. Lulu also arranges for your book to be printed and will sell you all sorts of editing and marketing services.
~ JBB
The publisher is responsible for every aspect of getting your book into print. This includes editing, cover design, marketing, printing, arranging contracts, and so on. They handle all financial and PR aspects. The may have an in-house printer or use whatever is available.
The only thing you (may) need to do is get an agent before talking to the publisher. Even that will vary. In some cases a publisher may help you arrange an agent, but this usually only happens if your text is sold gold and the publisher snaps it up quickly. Most new authors get an agent who helps them make the manuscript more attractive to publishers.
All a printer does is actually put the text into physical form. If using a printer without having a publisher you are self-publishing. This means you have to arrange all the details yourself including paying the printer upfront for the printing cost. Once you have the physical copies you then need to figure out how to sell them.
Publishers often have contracts where they control the copyright for a set number of years before rights revert to you. This is normal and it is your agent's job to help you get a good deal. Ultimately, most new authors don't break even on sales of their first book; publishers are investing in authors hoping that later books will take off, thus increasing sales of early books. This is why they need to hold copyright for a certain time, so they can capitalise on early books later if you take off.
If a printer wants copyright in any form or for any length of time, it's a scam. Do not sign anything with them. A printer is providing a service only, they are not involved with the product.
Note that under the Berne Convention the author automatically has copyright as soon as the work is completed, but in many countries it is necessary to register the work in order to protect it legally. In the US, for example, you cannot sue someone for infringement unless the work was registered prior to the lawsuit (or possibly before infringement, not certain).
Publishers often have contracts where they control the copyright for a set number of years before rights revert to you.
I do not believe that is true. Per the contract, the publisher is granted rights (e.g., First Rights, Digital Rights, Exclusive Rights, Foreign Rights, etc.), but not the copyright. Publishing rights, but not copyright.
Also, in your list of what a publisher does, don't forget distribution.
