Photo Shop-black color looks blue?

I am an artist and have drawn a line of pen and ink drawings for note cards, post cards, clothing and other items. I have scanned them to my computer. I am using Photo Shop to change the size and resolution to send to my printing company. When I open the scans in Photo Shop they look great. My problem is that when I print the drawings the black color looks bluish or shaded black/gray instead of true black. To fix this I have been using the paint tool to redraw over the black to get the color true black. I need to know if the printer will get the drawings the way they look on my monitor or will they look the way they are printed with off colors? Anyone know what I can do other than redrawing these on Photo Shop?