Bizhub C252 VPS and mixed colour/BW PDFs

Hi
I'm trying to print our church magazine on a Konica Minolta Bizhub C252 (the driver says VPS). I'm printing PDFs created on Adobe CS4 on a Mac, but the files are being sent to the printer via a Windows Vista box.

Some pages are black and some are colour. The trouble is that, whether the colour mode in the PDF is CMYK or RGB, the black is all being printed as rich black and coming through as a rather muddy brown on every page, and of course all the pages are being accounted as colour, which is expensive.

Does anyone know of a way of getting it to print the black as true black rather than rich black? I've found the 'RGB rich black' setting in InDesign and turned it off to no effect; is there anything else, maybe involving the drivers, that I can try?

 

I take it no-one has an answer? I'll try downloading and installing the PostScript drivers and see if that makes any difference.

 

You can print the black and white pages setting the print driver to color mode grayscale and get it to count as a black and white click, is this correct?

In the mixed color + black and white page document, I know a lot of people have troubles with copiers/printers counting the whole document as color. Are you sure all the blacks on the page are pure grayscale images? Are there any grayscale images that might be being exported to the pdf as cmyk even though the data is only in the k channel? Are there any crop/registration marks that are cmyk on top of eachother?

 

I had the same issue with my 6501. If you have a Post inserter tray you can print all your black pages first, then as you print all your color pages , used the mixed media setting to to insert the black pages as they appear. then use your finisher settings to bind as usual. This is a sure bet to get your black clicks as deserved.

I still had issues getting color clicks even in true BW PDFs. Konica assured me it should work, but it seems as long as your job setting states color , you get color clicks...

 

Thanks for your replies. The black pages are usually just black (K) text, and I've been checking carefully to make sure there are no extraneous coloured objects. I'm not using registration marks.

A black PDF in greyscale mode does come through as black. Annoyingly, if we make a mixed-colour Microsoft Office or Publisher document and print it direct from the application, the printer properly differentiates between the colour and black pages – it seems to be just PDFs it has a problem with. (I am not working in Publisher if I can avoid it!)

That's a good idea about the post inserter tray. I'll try to figure out if we have one and if so, how to use it. (I don't often go into the office so I don't actually know much about the printer setup.)

 

That could be why we had an issue for so many years. We almost exclusively use PDF to print. I never really experimented with printing from the application. Most jobs needed some sort of imposition that would have been a pain (maybe not even possible) to use a Microsoft program to accomplish.

We used the PI tray frequently for these jobs, and had decent success. I could surely give you a hand setting up the job if you need.
Its been a while since I have the Bizhub , but I'm quite sure I remember the process

 

I had this problem, check ur crop marks are pure black and not 4 colour
also in settings - Absolute will convert everything to 4 colour hence the black will look brown
Relative setting will print black and machine should give a mixed value in properties which black pages will count as black click