Printing a web page is more related to your choice of browser to Ask Ubuntu itself. **:-)**

 E.G. I'm currently using FireFox and that has an "Enter Reader View" mode in the address bar like this:

[![Screenshot of OP question][1]][1]

(The little page icon just before the <sup>**...**</sup> at the rightmost of the address bar itself)

Pressing that first and then printing prints perfectly at 150 on my printer.

  [1]: https://i.sstatic.net/WXdNl.png