Paper GSM suddenly affecting machine operation

[EdwardB]

This one is stumping myself and my lead Xerox tech

Xerox Versant 4100

Paper is standard bond, 20#/79gsm, 8.5x11. printing duplex. Paper is completely in spec for the machine.

Suddenly, the machine isn't able to pass sheets through the inverter. They get stuck in the fingers of the spring loaded gate. Cover stock is running without issue. Also, printing 1-sided to the finishing unit for 3-hole punch. All of the punches are skewed 15-20 degrees.

Tech replaced the inverter section in the machine. Same problem(s)... Even took apart the cooling bed drawer, made adjustments/cleaned/etc.

Now here is where it gets weird. Tech enters diagnostics, tosses bond into a tray configured as cover stock (200gsm)... runs duplex flawlessly. On a hunch, I edit the paper catalog entry. Change the paper from 79gsm to 100gsm (essentially lie to the machine), suddenly it runs flawlessly and my 3-hole punch job is punched flawless as well. What is the machine changing/doing different at 100gsm than it would do to 79gsm? I can assume temp and pressure, but to cause the machine to become incapable of printing duplex or send sheets through the finisher straight?

 

[namelessentity]

It's likely slowing down the print speed when you up the gsm. I know it's not the same machine, but we have two Primelinks that are also god awful with 20# and NCR. I've found either lying to the machine on weight, or running light weight text short edge fixes the jamming.

 

[DYP]

Long edge feed, long grain is a challenge at that thin of weight. Short edge feed, long will more likely work.