I have had problems in the past with the reproduction of blues in my color palettes on various jobs for print. Often they look fine on screen, but after reproduction they posses a ‘purple-ish’ essence to them, and sometimes they are perceived as purple by others that did not realize they were supposed to be blue.
During my time working in the prepress department at the Colorado Printing Company I learned a good rule of thumb for getting a ‘true’ blue. Maintaining a difference between the cyan and magenta color values as close to thirty percent(30%) as possible should allow your blues to look appropriate in your design after final production. For instance, instead of using C=100 M=100 Y=0 K=0 for blue try C=100 M=70 Y=0 K=0 for your cyan and magenta values. (See simulated example swatches below.)
Please keep in mind that this is simply a simulation of what might happen. Ultimately, a hard proof from your printer will give you the best indication on what colors you are going to achieve. Also, when it comes to printing, your investment is important for correct color reproduction. Some printers maybe able to save you money, but may not be able to alter individual colors for each job.