Om both my Laser printers I have problems with rasterisation.The printers adds its own raster on top of the raster sent to it.
On the OKi14ex the issue can be bypassed by raising the contrast to full.None of the printers has abilities to print 1-bit/black and white. Only greyscale and colour is available.
What I discovered is a program called GraphicConverter for OSX. When I load a pdf (print to pdf with MacprintX) and print, the problem is like before. Graphicconverter says that the pdf i 16mill colours, but when reduced in this program to 1bit the extra printer raster is gone!
Doing the same thing in Photoshop does not help. The programs seem to send the 1-bit data in different way (Photoshop is much slower too, maybe it continue to send 24bit data even when the contents is only 1-bit)
So. It semms there is something in the system or drivers that can not handle 1-bit data in a full colour print-file (regular postscript-crap-problem).Oh how I hate postscript.
Graphic converter proves that the data can be sent in another way.
MacprintX always seem to send more than 1-bit to the printsystem(?), even if the data is only 1-bit (Black or white). The printsystem seem to have problems understanding that this is really black and not some dark shade.
The same problem I have when sending 1-b Tiffs adverts to news-papers. Sometimes everything is rasterised, sometimes not. Their software cant translate it properly, when the black dots and text is not in a separate black only pdf-channel and they are too stupid to convert it for me... It seems as soon there is postscript somewhere in the chain, one never know what happens. Unfortunately OSX printing is based on postscript. Sigh.
Ps.There is still some banding (only seen in the raster) on the Xerox (like if the resolution is not exactly 600dpi) but the raster is gone, when printing 1-bit with GraphicConverter. On the 14ex there are no negative artifacts at all.
I am having someone testing the Samsung 550n ColourLaser for me. I report back when I know more.