Printing Solid CMYK

I have completed the head adjustments, and everything is printing well. I had been asked to print a large block of each ink color for testing purposes. Our customers have strict performance testing criteria, and we need to see how this off the shelf product does. When I attempted to print a solid block of Magenta, I saw some Cyan in it. When I printed Yellow, I saw both Cyan and Magenta in it. It appears the RIP is attempting color correction. I have started testing every option to eliminate this.