That is an easy fix, it's a PS setting and nothing more. 

Kowledge is power they say:

PS is a program that a user needs to know special settings to get proper results with any print system. Nothing to do with your RIP or any RIP, it's PS converting your Black and White channels and layers to a color profile before it sends the data to the printer based on your settings in the print Window.. You'll see that in the video. There are much better programs to print from than Photoshop, but you can make it work. Adobe is pulling more and more features out of PS in the new CS5 to prevent printing. They too would rather you use a proper print program to make your prints better and easier.

See video #2 (Photoshop Halftones) and you will be printing properly in seconds.

Let me know of your success.

http://www.softwareforscreenprinterstech.com/adobecorel