Colours not printing as they used to.

Hi, I hope someone may be able to help me.

I make small waterslide decals on an Alps printer.

 

Until recently I did all my work in Corel 3 and I had a very good range of colours that would print in a solid form. Some would print in a grainy or spotted? way but all was good. The more solid the colour prints the better as it means less of the base colour of the model shows through the decal.

 

A while ago I upgraded to Corel 6 and since then even the colours that used to print solid now come out in a grainy way.

I am using the same computer. The only thing that has changed is the version of Corel. I use a compaq presario with windows vista.

 

How can I fix this? Have I got the settings wrong? Any help would be appreciated.