C1000 heavy weight blotchy

[pabney]

Our Xerox C1000 has started printing very blotchy on heavier stocks. I think it might be a setting that got changed somewhere along the line.
If I print a test from the maintenance->dry ink cleaning for any of the colors (easier to see on cyan) I get mixed results depending on the paper I choose. But if I change the gsm of the problem paper the issue goes away.

100# silk text 140 gsm prints a nice solid cyan
100# silk cover 270 gsm prints very light and blotchy. Almost like it is starving for ink.
100# silk cover change the gsm to 140 and it prints as good as the text paper.

I have recreated the papers from scratch, and the only way I can get any kind of decent print is by lowering the gsm.

Add to this, the problem is on both of our printers.
About 3 weeks ago we had a specialist here servicing our printers for some other issue, and I think that maybe something has gotten changed in the engine set up. I do have a service call in, but was hoping someone out there would have an idea of what should be looked at.

Thanks

 

[PrintIT]

And you've tried adjusting the 2nd Bias Transfer Roll setting on the paper? On certain stocks, especially this time of year when the humidity starts dropping for us, we have to start playing with that.

 

[pabney]

We have never had to change this before. Is this change a daily thing, or just seasonal?

 

[wonderings]

We have never had to change this before. Is this change a daily thing, or just seasonal?

I find it seasonal, temperatures dropping or rising, along with humidity. When I start noticing this on our Versant 2100 I look at the transfer settings and usually makes the right difference.

 

[PrintIT]

Seasonal for us - It's usually only in the fall and spring for us when humidity starts changing, and only for certain stocks. Some stocks keep running fine with no adjustment.

 

[pabney]

Adjusting the 2nd Bias Transfer Roll setting on the paper to -50 did make it smooth. However, the color is now completely wrong.
After learning about this setting, I am now wondering about my current method of calibration and color control. Although it seems to have worked for the past 4 years. Hopefully, the braintrust is willing to put up with my ignorance and walk me through the following questions.

1. We have the full width array. Using the Auto Tone Reproduction Curve you can choose Coated, Uncoated, and User. Are these kept in the system separately, and applied based on the paper being printed?
2. In the same screen, the Auto Density Uniformity, does it matter what paper I choose for this?
3. We currently have 1 output profile, that we set up using our most common sheet, 100# gloss text. Do I need more? I hope we don't need one for every stock.
4. Say we do an output profile for coated cover, coated text, uncoated cover, uncoated text and assign them appropriately. If I have to change the bias for 100# Silk Cover, but not 100# Gloss Cover, would I need a profile for just the stock with the bias changed.
5. How do I know if I have set the bias correctly. There is a test sheet that prints out, but do I choose just by eye?
6. On the Fiery rip we currently use the ES-2000 for setting up our profile, and for daily calibration. Would the Full Width Array be a better choice for out daily calibration?

Ok, I think that is all I have for now.
Thanks for the help.

 

[kdw75]

I used to profile for coated and un-coated sheets, but now just profile, and calibrate on 100# gloss text, which seems to always print well. On heavier covers you can run the voltage test sheet.

On our Versant they have the 2nd BTR voltage and another voltage that I am not familiar with. I always adjust the 2nd BTR.