Printing Digits!

$1 - \text{digit} \Rightarrow \text{There are 9 such numbers} \Rightarrow \text{Total number of digits} = 9$

$2 - \text{digit} \Rightarrow \text{There are 90 such numbers} \Rightarrow \text{Total number of digits} = 180$

$3 - \text{digit} \Rightarrow \text{There are 900 such numbers} \Rightarrow \text{Total number of digits} = 2700$

$\vdots$

So if the printer printed up to page 999, it would have printed $9+180+2700=2889$ digits.

But since we want to find out which number corresponds to $3189$ digits, we subtract them:

$3189-2889=300 \Rightarrow$ This is total number of digits on pages that are numbered with $4$ digits

$300\div4 = 75\Rightarrow$ This is the number of pages with $4$ digits

And since the $75th$ 4 digit number is 1074, there are $\boxed{1074}$ pages in total.