Check the Scale setting in the Print Preview window or in File > Page Setup. "Shrink to Fit" or "100%" usually works best.

I did confirm that my page setup is set to "Shrink to Fit"

If Firefox is not using the whole sheet of paper, or otherwise misunderstands what is contained in your printer's paper tray(s), that can be caused by Firefox having extracted the wrong paper size settings from Windows when reading the print driver data. Clearing it involve some heavy clicking:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste print and pause while the list is filtered

(3) For each setting that specifically mentions the problem printer, right-click and Reset it. The fastest way is to right-click with the mouse and then press the r key on the keyboard with your other hand.

Here's the footnote: In a couple threads involving printouts that used a small portion of the page (on Brother printers), the preference printer_printer_name.print_paper_data was set to 256 and when the user edited it to 1 that by itself fixed the paper size problem. If you use a Brother printer and see something other than 1 there, you can edit the value by doubling-clicking it or using right-click>Modify to see whether 1 is the number you need.

Thanks for the idea. Unfortunately, it did not solve the problem. I reset all of the print settings associated with that printer. After doing so, I closed and reopened the about:config and found no listings at all for that printer that I had reset, I also played with resetting some of the other generic print settings, but, they didn't help either. I also noted that printer_printer_name.print_paper_data was set to zero and I tried it with the setting of 1. It made no difference.

One thing that might be better now and/or might help diagnose - If I have the HP laser printer selected as the default printer before launching the print job, the print job is formatted correctly. If I have the receipt printer selected as the default printer, then change my printer to the HP Laser Printer while launching the print job, then, the print job is formatted like a receipt (all compressed into the top left corner of the paper).

Any more ideas? It seems like it must be resolvable because my other computer functions correctly.

In Firefox the default printer is the "last used" printer. Use a different printer just once, and the "default" is changed to that printer.

Firefox does not use the "default printer" as set in the operating system; other than the first time any printing is done thru Firefox. So the issue may be with what you are assuming is the "default printer". Seventeen years on the internet - Firefox (along with the old Netscape browser and the old Mozilla Suite which was the same as Netscape when the Mozilla Foundations was first founded in 1998) is the only application which had its own idea as to what would be the "default printer". IOW, it works slightly different than any other application does, IMO.

"Receipts are printed from a cloud based app using firefox as the browser." Are you using the Print button on the web page that is part of that online app? If so, that type of "button" usually by-passes Print Preview and send the print job directly to the "native Print dialog" box where the user can select the printer that they want to be used.

"... then change my printer to the HP Laser Printer while launching the print job, then, the print job is formatted like a receipt (all compressed into the top left corner of the paper)." Does that refer to what the Print Preview displays before printing?

If so, that is due to the user not being able to select a different printer from within the Print Preview display. It is showing the formatting for "last used" printer, not the printer that you want to use, due to "mutually conflicting or dependent conditions" [IOW, a "catch 22" dilemma] with the "last used" manner with how Firefox works.

If you proceed to "Print" from the Print Preview display you should be able select the printer you want to use and the actual printed page should be correct for that printer. Bad thing is that until "something" is printer you can't "preview" it.

I hope that is clear and understandable, and not too disjointed of an explanation.

If I was faced with that for an activity that I did frequently, I would set up a 2nd Profile to be used with that online app. This "last used" for the default printer is saved per Profile; you won't run into this quirk with your main Profile. We can explain how to set up and use a 2nd Profile, if that's how you would want to proceed.

Yes, I follow your explanation. It is what we experience all the way down to the last paragraph, "If you proceed to "Print" from the Print Preview display you should be able select the printer you want to use and the actual printed page should be correct for that printer." Even after selecting the HP printer, the actual printed page is squeezed to tiny print occupying just the top left corner of the page. Like I say, our other computer functions as you describe. On some of our printouts, we use the print button provided by the cloud software. It goes straight to the screen to select the printer without displaying a print preview. On other printouts, we use the print function from the firefox menu. It displays an inappropriately formatted print preview, then, clicking that print button allows you to select a different printer. Both methods produce the same incorrect results. What is causing firefox to fail to reformat the print job to the selected printer? Having the correct print preview is not a concern, just want the actual printed paper to be right.

We do override the "last_used" function so that it keeps the default printer. We need this to save time printing receipts while serving customers. There were too many times that the receipt went to the wrong printer. To do this, we set the parameter "print.save_print_settings" to false. Setting it to the default - true - does not fix this problem but it does create mistakes with the getting the receipts going to the proper printer.

I would be interested to learn about using a 2nd profile. However, I suspect we will have the same aggravation because we would forget to switch profiles until after getting the bad printout.

I have also tried Firefox's reset feature. The problem persisted through that.

Any other ideas?

Hi wocruc, Firefox's print preview should display whatever is appropriate for the printer that is currently expected to be used (the one displayed when you call up the Print dialog). There isn't a way to preview on the printer of your choice. That would be a good feature. Or maybe someone could create an add-on for that.

Either way, Firefox should use the paper size/type settings it previously extracted for the target printer and not switch them. That part is hard to understand. Does it work any better if you do NOT use preview and call up the print dialog using Ctrl+p?

Regarding two profiles: what I think Ed is suggesting is that you have two instances of Firefox running, each in a separate profile. By adding a theme to the toolbar area, or otherwise modifying the browser's appearance, you can easily spot "which Firefox" you're in. Now, if you need to switch the same page back and forth between printers this would not work, but you can have both Firefoxes logged into the same site (assuming the site's security doesn't prevent it) to work with different aspects of it. Of course, if you're going to do that, you could log in with Firefox and another browser and dedicate one of the two to printing receipts.

No difference with ctrl+p. Using a different browser is also the suggestion of the software support people. I'm just bothered by having to use that workaround for one computer when the system functions just fine on other computers.