Preview prints lose the bottom part of the page

Question

Yesterday, after doing an update (which only updated iTunes, so it's probably not what caused the problem), I found that all print jobs from Preview (and a few other programs that I've tried) are missing roughly the bottom 1 cm of the page.  I've grovelled through all the settings and preferences that I can find, and I've made various other things change, but no matter what I do, nothing makes the bottom line of text appear on the paper.
Preview shows all the text, including the bottom line, and when I use the "PDF" button to "Open PDF in Preview", it shows the page with the bottom text.  But when I print the page, the bottom line is blank.
The printer is remote, controlled by CUPs on a machine down the hall.  When I scp a PDF file to the server and print it there, it prints fine, and the bottom lines are always included. Then when I go back to my Macbook Pro and print exactly the same PDF file on the same printer, the bottom line is again missing.  This shows that it's not a problem with the printer or the server's CUPS software; it's gotta be something on my Macbook Pro that changed.
The usual disclaimer applies:  I haven't (knowingly ;-) changed any print-related setting recently.  (We've all heard that one before, right? ;-)  Since the problem appeared, I've of course changed lots and lots of settings, trying to find something that affects the problem.  But the most recent change before this problem appeared was a couple of months ago (when another upgrade broke all remote printing, and I had to delete all the printers and reinstall them). 
A possible clue is that, when I use Safari to load a PDF from http://localhost/..., the page shows as usual, and I get the same drop-down from CMD-P that shows a preview that has the entire page.  But when I print it, the entire page is shifted vertically so that the top title line of text is missing - and the bottom line has only its upper half, with the bottom part of all the characters missing.  Again, the blank strip at the bottom is roughly 1 cm.  Actually, a quick check with a ruler says that it's 12 mm.  But I don't know how to use this info, or how to tell Safari to fix the missing title line.  The missing bottom half of the bottom line seems to say that it's not that the PDF has something wrong that suppresses the text entirely; it would seem to say that somebody is deciding to impose a 12-mm bottom border for some unknown reason.
Any idea where I should look to fix this problem?  Is there a relevant troubleshooting guide somewhere that I should know about?
(It sure would be nice to have a known way to say "Just print exactly what's on the Preview page; don't try to do anything clever with it." ;-)

Answer 1

That doesn't sound quite right.  Tests on the server shows that the printer (HP L7680) can in fact print up to within 3 mm of its edges.  The test pages show this, and assorted tests with "real" PDF pages in the past have verified it.  It worked from my Macbook up to a few days ago, and tests from the server show that the printer hasn't lost the ability to print close to the edges.  In fact, my wife printed a page from her iMac a while ago, and it showed stuff (images and border lines) up to about 4 mm from the edges.  It's only from my Macbook Pro that suddenly the bottom 12 mm gets blanked out. 
Actually, I did try a test from the server with the "borderless" setting.  The software enlarged the image to be bigger than the page, for some reason that I don't understand, but the result was that the printer printed right up to the very edge of the paper; there was ink visible on the edge of the sheet.    So the idea that the printer "can't" print close to the edge is wrong.  The printer doesn't have a problem here; it's being told by some software on my Macbook Pro to blank out the bottom edge. 
I just tried another test of this:  I told Preview on the Macbook to print the page at "Scale: 120%  ", and checked "No automatic page scaling".  Preview showed the text going off the page at the top and right edge,  The ink stopped about 3 mm from the top and right edges.  But the bottom 12 mm, including the bottom line of text, was blanked out.  This, plus the tests on the server, shows that the printer can print up to 3 mm from the edge of an 8.5x11 inch page.  And earlier tests that produced the bottom line with only the top half of the characters shows that it isn't just dropping the bottom line; Something on the Macbook is explicitly blanking out the bottom 12 mm (but not doing the same on the top and right edges.
And whatever is doing it doesn't happen on my wife's iMac; she can print close to the bottom edge.
I'm now wondering if I should uninstall the printer on the Macbook, and see if I can reinstall it to match the iMac's settings.    But if the problem is something in the Macbooks system libraries that's forcing the 12-mm bottom margin, that probably won't work, either, and the "Letter" paper size settings presumably come from some library file, because it won't permit me to change those numbers.
Anyway, I'll try your suggestions, probably in the morning, and see what happens.
About the Borderless type:  I find that when I try setting the Paper Size to "US Letter", it gives me another menu, with "US Letter" and "Borderless 8.5 x 11 in." entries.  If I choose the Borderless, it pops up a window with a warning that this is only allowed for HP Premium Plus Photo Paper, which is in what it's set to.  It says it's "not available when Paper Type is set to Plain Paper", which it won't allow me to do.  (That choice is greyed out.)  It seems odd that it would warn me that it won't work for a setting that it won't let me use anyway, and say that I must use the setting that I am using.  Anyway, I've tried this "Borderless 8.1 x 11 in." setting, and it comes out the same as the "US Letter" choice, with the bottom 12 mm blank.  Both print to nearly the top and right edge if I set the Scale to 120%.
(And that damned "Automatically rotate each page" is checked again. ;-)