Dot matrix printing on c sharp

Question

i have a bill format as follows

                        Bill

SL No        particulars        Qty        Rate
-----------------------------------------
1                Nokia 6300        1        4500
2                1100 Charger     1        80
...                ...                  ..        ..
...                ...                  ..        ..
...                ...                  ..        ..
In this bill report the width is constant but length is depends upon the particulars  

it is printing on dotmatrix printer and paper size is A4 (set in cristalreport)

So i want to stop bill printing on last particulars or last line printing