photo screen quality from digital duplicator

[DTP-007]

Can a 600 dpi digital duplicator compete with a laser printer for black and white photo screen quality?

 

[Jeff]

I've looked at digital duplicators a few times in the past because of the extremely low cost per print + low initial equipment investment for printing black and white.

The 600 dpi rating for a digital duplicator is 1-bit (quite literally each of the 600 potential dots per inch is a pit burned into the wax master which is wrapped around the ink drum for ink to flow through onto the paper as the drum spins.)

However, when using any of our current color copiers to print black and white only we have 8-bit per color (or black.)

600 dpi x 8 bit (256 shades) is a world of difference from 600 dpi x 1 bit (1 shade) in terms of photo and tone reproduction. For line art the digital duplicator would be ok; for text it would be fine. But for photos or solids, I don't think it's close.

 

[awbunny]

In a short answer -no-. We do short run (100-200) copies of books on a Gestetner 5490 and if there is a photo of any quality we have to run it laser. We do down and dirty photos on it but those customers do not care about quality, only price. For text and simple graphics it's great, just don't read to much into the 600 dpi. You can do some dark stuff on it if you use the skip feed but even then... Good luck!

 

[DTP-007]

Thank you Jeff. Thank you awbunny.

Is there a noticeable advantage between the 600 dpi digital duplicators and the older 400 dpi models?

Also are you usually able to run your digital duplicator at full rated speed ('up to' 120/minute), or do you have to run it slower to prevent quality issues?

 

[awbunny]

I would go with the 600 dpi. You are already fighting quality issues at 600, I can't imagine 400. We never run at top speed. What you are printing determines speed. Printing just text it with chugs along, add a small photo or solid you have to experiment. Any large image you have to run it on skip feed to load the drum with ink between passes. We are doing a short run book now with photos. My wife ran the photos on a laser printer then ran the text on the duplicator to match the rest of the book. A pain but we charge for it. Overall the duplicator is worth it if you have the work for it. It has taken awile to figure out what it will do but 800,000 impressions later we have not had any problems we couldn't fix. Buy the service manual on ebay if you get one, the factory tech charges 130 an hour and didn't impress us. A heads up, ours does not have a doubles detector, every job we flip though to find skips, not a big deal but it does skip. From what I've heard the ink on a Riso dries fast. On our Gestetner it takes a while (we wait overnight to run flips). It's cheaper than a copier for a small shop and easier than inking up our press. Good luck!

 

[birdz]

dont buy a digital duplicator thinking it will compete with a modern laser printer in terms of quality

digital duplicators are designed to be quick, cheap, and versatile.

 

[art post]

Actually, there are many printers using digital duplicators. Ricoh has a system HQ9000 that is suitable for envelopes, ncr, and two up printing on 11x17 (speed still maintains 120ppm).

You can also get some great halftones by altering the line screen. I am not a printer, however I have made it a point to be an expert in duplicators. Duplicators are not for everyone, however you will get very good quality with out going to the press. Dups are also great for short run work.

Take a look at the latest offerings they have PSIII, ethernet, Hard Drives, and when printing from a MAC or PC the quality for text will rival any laser printer, solids will vary depending on how large the knock out is (poly plate will stretch more with large solids).

Do a google search for Docusultant

 

[birdz]

I don't think he was just talking about quality of text. Photos, halftones, and screens just wont look as good as those coming off of a laser printer.

Even fine script text won't look as good.

Duplicators are great and can make you some good money but don't oversell it or you'll just piss people off.

 

[plotter]

i have a riso, digital press and litho presses.
the riso is only good for cheap work flyers and such, where price is more important than quality, even black and white invoice books and such things i would run on litho..
in a nutshell risos image quality is crap compared to litho and digital, but there is always room for one as they are inexpensive and rarely break down..

 

[TomC]

If anyone wants samples from a RISO duplicator or the RISO HC5500 (full color inkjet printer), feel free to email me...I'd also be happy to print any files that you want as well. TCracovia@RISO.com Our website has tons of info. as well.
Thank you.