Thin Print Substrates - Konica Minolta

beeline

Member
We want to transfer smaller runs of 1/1-colored jobs from our offset machine to our Konica Minolta 6120 (vacuum feeder).

The 51gsm paper we’re using for our offset press (low volume, high opacity, recyling) won’t run on the 6120 at all (and we’ve had several highly experienced technicians give it a try).

I’d be interested to learn from your experiences with (very) thin substrates on KM/6120 or other toner-based digital printing systems - particularly those that are available for purchase in the EU/Germany and would be very grateful for any recommendations.

Because of significant number of pages, as well as the manuals’ often small format of the manuals, low volume is more important than light weight / low gsm.
 

DYP

Well-known member
Probably be best to explain exactly where it is failing, grain direction, duplex simplex, etc.
 

jwheeler

Well-known member
I agree with @DYP that more details would be helpful. Is it jamming before the engine, in the engine, or in a finisher?

I haven't had the opportunity to run media that thin however, there are some things I'd try if they haven't already been suggested by the techs:
  1. Try running it out of drawer 4 which is the straightest paper path
  2. Try changing the orientation of the paper from long edge feed to short edge feed.
  3. Try changing the process speed in the paper expert adjustment section
  4. If the jamming is happening from the paper deck, try turning the side air or lead edge air down or off.
 

beeline

Member
The spec sheets says 40–300 gsm, so I'd ask for it to be escalated to a specialist.
We've had a couple of very experienced technicians have a go at it, without success. They're currently researching a list of low-volume substrates to propose as alternatives.
 

beeline

Member
Probably be best to explain exactly where it is failing, grain direction, duplex simplex, etc.
@jwheeler and @DYP – here are a couple of additional details:
  • duplex print
  • tried both short grain and long grain (with short grain not even one sheet made it through)
  • not using any finishing equipment
  • it's failing in the engine, mostly after image is transferred to the substrate
  • when a sheet makes it through, in about 50% of the cases it shows folds
 

beeline

Member
I agree with @DYP that more details would be helpful. Is it jamming before the engine, in the engine, or in a finisher?

I haven't had the opportunity to run media that thin however, there are some things I'd try if they haven't already been suggested by the techs:
  1. Try running it out of drawer 4 which is the straightest paper path
  2. Try changing the orientation of the paper from long edge feed to short edge feed.
  3. Try changing the process speed in the paper expert adjustment section
  4. If the jamming is happening from the paper deck, try turning the side air or lead edge air down or off.
thanks for the additional pointers.
  1. done that
  2. printing SRA3 so short edge
  3. lowered process speed to minimum
  4. feeder transfer to main engine is fine
 

beeline

Member
Thank you all for your hints and additional questions. We've tried a variety of things machine-side and I don't think we'll get this substrate to run in an efficient/productive way over the course of long runs (which we are aiming for).

The burning question to me is: which low-volume (and low gsm) substrate(s) have you had good results with?
 

gregbatch

Well-known member
"The 51gsm paper we’re using for our offset press (low volume, high opacity, recyling)"

Do you mean it is recycled paper? That is most likely a major part of the problem. Recycled paper tends to have much less rigidity than a non-recycled sheet, and with a such thin sheet it will tend to fold up on itself before reaching the next roller. When running a thin sheet you want the grain in the direction of travel. Try getting samples of a non-recycled sheet. I have trouble running a 50# recycled sheet. It makes it through the machine, but then wants to fold up in the delivery tray because of the slope of the tray. The thinnest I've run is 40# (about 59 gsm). I've never had to run anything thinner. Sounds like what you are trying to run is a 35# groundwood, which can vary greatly in rigidity, usually proportional to recycled content. I don't think it is impossible, but you will have to find that perfect sheet.
 

Stickman42

Well-known member
Thank you all for your hints and additional questions. We've tried a variety of things machine-side and I don't think we'll get this substrate to run in an efficient/productive way over the course of long runs (which we are aiming for).

The burning question to me is: which low-volume (and low gsm) substrate(s) have you had good results with?
On my Xerox Nuvera I've been able to run 40# offset/opaque fairly reliably. Sheet size, grain direction, long vs short edge feed all played into arriving at a working solution.
 

kslight

Well-known member
I used to run large volumes of 16# (60gsm) through Xerox docutechs…it was very sensitive to the direction of the curl and humidity, and some batches simply wouldn’t run, how long it had sat…and this was before you had advanced operator settings to tweak. Start with good paper, I don’t know how many options there are in cut sizes however (this paper was getting rare for me years ago before todays paper issues). I think these kind of stocks might be more common on roll fed devices?
 

beeline

Member
On my Xerox Nuvera I've been able to run 40# offset/opaque fairly reliably. Sheet size, grain direction, long vs short edge feed all played into arriving at a working solution.
40# = approx. 60 gsm (?). We're trying to find a substrate that runs on a toner-based / sheet-fed machine at max. 51 gsm with 1,00 bulk multiplier (i.e. around 50 cm3/g).
 

beeline

Member
I used to run large volumes of 16# (60gsm) through Xerox docutechs…it was very sensitive to the direction of the curl and humidity, and some batches simply wouldn’t run, how long it had sat…and this was before you had advanced operator settings to tweak. Start with good paper, I don’t know how many options there are in cut sizes however (this paper was getting rare for me years ago before todays paper issues). I think these kind of stocks might be more common on roll fed devices?
@kslight - good observation. The 51g material we're using in our offset press is cut to size for us (from a roll).
 

beeline

Member
"The 51gsm paper we’re using for our offset press (low volume, high opacity, recyling)"

Do you mean it is recycled paper? That is most likely a major part of the problem. Recycled paper tends to have much less rigidity than a non-recycled sheet, and with a such thin sheet it will tend to fold up on itself before reaching the next roller. When running a thin sheet you want the grain in the direction of travel. Try getting samples of a non-recycled sheet. I have trouble running a 50# recycled sheet. It makes it through the machine, but then wants to fold up in the delivery tray because of the slope of the tray. The thinnest I've run is 40# (about 59 gsm). I've never had to run anything thinner. Sounds like what you are trying to run is a 35# groundwood, which can vary greatly in rigidity, usually proportional to recycled content. I don't think it is impossible, but you will have to find that perfect sheet.
Very good insight. Recycled paper will most probably have a significant impact. I've reached out to a couple manufacturers to see what they're saying regarding runability of their low bulk substrates on KMs.
 

printer in heart

Active member
I have KM 6120 and I use Lynx 40lb offset to print. My final book is 6 x 9 with a bleeds on 6" so I print 2 up on 13 x 10 paper. It works fine. I use Book/News settings 50-54gsm or 55-61gsm. It works fine with the either settings. I6120 works pretty good. I had Nuvera before for a very long time. I think 6120 works slightly better, less paper jams then Nuvera. Good luck
 

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