Would anyone know if it has the printer tracking function?
You can check it with a blue light. You can also use one of the following
tricks to check if the dots appear :
Making the dots visible
By design, it’s nearly impossible to see the dots with the naked eye, so
you’ll want a way to magnify any page that you want to inspect.
Using a microscope or magnifying glass with magnification power of 10x or
better to view a blank part of a printed document should allow you to see the
dots, if they exist.
If you want to make it easier, use a bright blue LED flashlight in a dark
room, which should turn the yellow dots a dark blue or black.
If you have a good quality scanner and a graphics program that can zoom and
invert the colors, you can also find the pattern, which should repeat itself
throughout the page.
source:
https://eu.azcentral.com/story/money/business/tech/2017/06/09/your-printer-tracking-you/379755001/
And I want to print my works on postcards. I already printed them, more than
100 postcards, but I cannot put a picture on the exact center of a paper
This can be related to built-in margins in the printer's options. I faced
this problem once while printing cd covers. First check if the margins are
set to 0 in Trisquel's parameters. If the problem persists, you can try to
disable the built-in margins by printing from the commandline :
lpr -o page-left=0 -o page-right=0 -o page-top=0 -o page-bottom=0
ファイルネーム.pdf
