This article provides instructions on configuring Mozilla Firefox printer settings for the following types of printers:
Regular- A4 Size
Receipt Printer
Dot Matrix Printer
Regular- A5 Size
Receipt Printer Settings
Press ALT on keyboard to open Main menu.
On the Firefox main menu, click File, and then click Page Setup.
Click the Portrait radio button.

4. Clear the Shrink to fit Page Width checkbox.
5. In the Scale field, enter a value between 90 and 95. (The value can be
changed depending on whether the item to be printed is being
printed appropriately).
6. In the Margins and Header/Footer tab, enter 0 for all the margins.
7. For all the Headers and Footers, select --blank--.

8. Click OK.
For A4 Printer
Modify the settings as follows:
In the Format & Options tab, select the Orientation as Portrait.
In the Scale field, enter 89.
Go to the Margins & Header/Footer Tab and enter the following value for alignments:
Left Margin:25
Right:12.7
Top:0
Bottom:0
For A5 Printer
Modify the settings as follows:
In the Format & Options tab, select the Orientation as Portrait.
In the Scale field, enter 88.
Go to the Margins & Header/Footer Tab and enter the following value for alignments:
Top: 0.0
Right: 0.0
Left: 15
Bottom: 100