Alternative RIP for Konica Minolta B&W printer

[Puch]

We started using our new KM 1250P just two months ago, and already faced one job which became quite a headache for us. While the machine seems to be a workhorse, good for most general-quality materials, the screening isn't up to our expectations.

When we start using coated papers (any coated stock, but our main focus here is to print on LWC, mostly used in heat-set printing), screening artifacts become very visible. Our goal is to mimic the screening used in offset litho, or the screening of color machines like the KM C1070 or C1085.

I know that the KM 1250P's hardware resolution of 1200 dpi (in theory) isn't enough to produce a good quality 150 lpi screen (or better), but I do remember that in the old days of film imaging we had some very spectacular printed results with 120 lpi and 133 lpi screens (Balanced Screening from AGFA) using only 1200 dpi resolution on the Avantra 44.

What I see here is that the stock KM RIP, integrated into the machine, isn't capable to produce a good quality 120 lpi screen. In the "optimized", stock 133, 150, 171 lpi screens (45 degress, dot shape) I see ugly patterns, disturbing repetitons, too.

Do any of you heard a third-party RIP solution for BW printers, doing professional quality screens, or I have to live with the current setup?

Thanks for any feedback!

 

[matty]

if i'm not mistaken, there is an option for you to choose several types of screening at the printer driver. the option fell under the imaging (or quality) tab. You can play around with it.

 

[Steve0]

What OS and print driver are you using? You should be using the PS Plugin driver. The [Imaging] tab in that driver has a lot of controls you might want to play with, including Resolution, Screening Method, Screen Frequency, Screen Angle, Dot Shape, Tone Curve (from the standalone Tone Curve Utility), Image Density, etc., etc., and my personal favorite for when the document contains RGB images, Use CIE Color. There is much to explore here.

 

[cosmo]

as mentioned, use the printer driver for that machine, lots of options, would do just as well as any third party rip

 

[Puch]

Dear matty, Steve0, cosmo,

I'm way beyond that; of course the first step was an exhaustive test using the latest PS driver downloaded from the Konica repository. And yes, you're right, there are plenty of options in that software, yet no setting combination will diminish the "laserprinterish" feeling of the printed output.

Basically, there is a "press" with a stellar price tag, capable to handle any paper with very high precision, laying down dots in a true 1200 dpi device matrix, but the RIP introduces such artifacts that the output can't be regarded more than the output on an office laser printer, sold for 100 USD nowadays.

I also did the following test:
1.) produced a test page in InDesign, saved as PDF (grayscale elements only),
2.) printed the page using the built-in RIP on the KM 1250P, with 150 lpi dot raster,
3.) opened the PDF in Photoshop as a 1200 dpi grayscale image (no antialiasing)
4.) converted the grayscale image in Photoshop to a 1200 dpi bitmap. Upon conversion, I opted to produce a 150 lpi screened image.
5.) saved the resulting image to be a PDF (containing only one large bitmap image)
6.) printed the second PDF on the KM 1250P with the same settings as in 2.)

Since the internal RIP of the device can't do anyting with the bitmap (it is the correct device resolution, so resizing isn't needed, and there is no grayscale, so screening won't happen), it simply prints out the file dot-by-dot.

Now, this second output has some visual improvements over the first, which proves beyond doubt that the output can be better using this device.

What I feel is that the internal RIP is cutting some corners (I guess because of the limited processing power & needed imaging throughput) which means, the produced halftone screens are far from perfect.

I do hope that there is a 3rd party solution to improve the output using a better screening technique.

 

[Steve0]

KM does offer an alternative RIP for the 1250: the Creo IC-309m. Contrary to what you might think (after all, it *is* a Creo controller), there are very few image quality controls with which to control the quality of the output. And, it connects to the engine *through* (not bypassing) the KM controller.

 

[Puch]

Interesting note, thanks, Steve0. Our reps always told us that there is "big controller" in the works, but they stated that it will be a Fiery one, for a hefty price tag. I would be glad to have more info about this controller, since the online information is only a marketing material. Do you know the price tag of such a system?

After all, I don't really care about the number of image control settings: if I can set 133 and 150 lpi, and these rasters come out perfectly, I wold be happy for the time being.

 

[Steve0]

Let's just say the IC-309m is not cheap.

There *is* a Fiery option for the 1250. I hadn't thought of that, because it takes more the form of a DFE than a controller, with intelligent load-balancing and make-ready capabilities -- but it does rasterize. It's called Fiery Central.

 

[Puch]

OK, I found that DFE too, called Fiery Central Solo - thanks for the information. I have to find a way to test the screen quality of that solution.

Another way would be to use an external RIP with some advanced screening, then upload the TIFFs to the engine. Is that possible?

 

[Steve0]

You need to get your hands on the bizhub PRESS 1250 Printer User Guide. There you will see documented a feature called "Direct Print," in which it is possible to download to the machine PCL, PS, or TIFF (6.0 compliant) files.

On the machine console, press Controller > Direct Print Setting > TIFF Setting, and in there you can enable/disable Auto Paper Select (whether to print automatically on appropriate paper size for the TIFF image) and set Image Position (select Left, or Center).

Well, that actually pretty much sums up everything that manual has to say about TIFF printing.

Direct Print is the ability, using PageScope Web Connection in a web browser, to send PDF, TIFF, PS, PCL, text, or PPML files to the machine (documented in the same manual).

 

[Puch]

Thanks for the directions, I will try that tomorrow, will be back with my findings.

 

[dpolglaze]

Hey, Puch and group,

I worked with Creo engineering to release the 309M. We then bought the first units in the US. We deal pretty much only with mail and other high volume shops, so we've sold a ton of the KM 1200 and 1250. We used to out the EFI MicroPress on the 1200 and now the Creo on the 1250. While it's an excellent RIP and is great for workflow and job management, it won't necessarily improve your screening on the 1250 even though it has a custom gradation/curve tool.

I have worked a little with Fiery Central. It is really, really expensive and it's not a RIP, but it could potentially help you out. I'm not 100% certain. As you said, you have to get proof in your dealer showroom or through a trial.

Couple of pointers on the 1250 and PageScope. Make certain that you are setting your trays correctly for the paper you're using--actual paper type and weight as the engine and controller treat the paper differently depending on these settings. The PageScope software should have come on a disk with your machines, but might not be the most recent version. The job parameters of this "direct print" tool are controlled through the "Controller" button at the bottom your engine's touch screen. There's a few weird things about installing and using PageScope including SW Dip Switches and the 1250 may not show up in the printer list when you configure it.

As stated, the PSPlug driver will grive you the most control over screening in the "Screening" tab.

If you want some phone help on any of this, I'd be happy to assist. Contact me at dwightpolglaze at gmail

Thanks and Happy Printing!
Dwight

 

[Puch]

Thanks for the extensive info, Dwight. Sorry to say, these controllers seems to be too sophisticated to be offered in our area. I guess this is mostly because of the prohibitive price.

I further examined the screen buildup, tried several settings in the PS driver's "Imaging" tab. Also tried some screened TIFFs generated with PS, fed to the engine via direct print. The sweet spot for me, using this 20 years old screening tech is 150 lpi or 171 lpi, depending on the images & graphics.

I think the solution can be a standalone RIP with some more up-to-date screening algo, automatically transferring it's output to the engine. I will ring back if I found something promising.