Colour Text on grey background

Hi,
I am reasonably new to CMYK printing and I had a quick question regarding printing coloured text on neutral grey. I have been doing some tests but I don't know if it is even possible. I have created a file with a grey background that is only 30%K and then added coloured text to it in Photoshop. I end up getting a line running across the printed area where the text is which is grey with a hint of the CMY colours. I can eliminate the line by printing the grey background with the CMYK colours but is it possible to have the coloured text and a neutral grey? I would be grateful for any suggestions. Thank you.
David

 

What type of engine?
What type of madia?
What type of RIP
Can you post photos?

More info makes it easier to help you.

 

its on a Canon Image Runner Advance 9060. I'm using Command workstation. Printing on to 100g high grade coated paper but it occurs on all papers I have used in printer. The file was created in Photoshop then placed in an InDesign document and then exported to pdf, although, it happens also if the file is just saved as a pdf in Photoshop. The line is visible after the RIP processes it, I can see it in the preview. I have provided an example via an attachment of the what file looks like before the RIP processes it and after. Thanks for your help!
David

 

I solved the problem

I solved the problem here. Thanks for your help.