SKEW IN 6501

[levino]

HI ALL,
My two 6501 is having skew problem in duplex,and is not cosistant.The first print will be good and if we print 100 sheets,the each paper will have different registration up to 5mm.one is run 15000and the other 75000 clicks only.
Customer is siting in my head,pls help me with some solution
thanx in advance

[RRodgers]

Increase the loop for the duplex reg.

[brian155]

is it skew or registration? 5 mm front to rear reg problem can be due to cassette position never had a major problem on lead edge reg. the skew is adjusted by loop and cd and fd correction.

[ebm]

Clean the ADU brass bushings for the white idler rollers. They get sticky and bind up when feeding paper thru ADU. Might also what to check/clean the registration bushings.

[Si@danwood]

HI ALL,
My two 6501 is having skew problem in duplex,and is not cosistant.The first print will be good and if we print 100 sheets,the each paper will have different registration up to 5mm.one is run 15000and the other 75000 clicks only.
Customer is siting in my head,pls help me with some solution
thanx in advance

Welcome to our world as Bri says conformation of the actual direction of Skew would help us help you..Si

[levino]

Thanks All,

It is skew problem only,not with registration and not consistant
Eg:If I print a 13x19 document,think the left margin on the leading edge is 20mm but when it is going to the trailing edge the margin is reducing and will be approx 16mm.
But in the second paper it will reduce to 15 or 18.each paper will be different margin.
It occuring from all the trays for all gsm papers.

[Si@danwood]

That amount of skew is extreme.You normally get around a mm shift but 5mm is a lot!!I would be looking to make sure that the entrance plate to the Registration area has not buckled(paper get jammed in here and the plate can lift when the ADU unit is removed) A good indicator is turn the lower transport rollers whilst applying a small amount of pressure on the white nylon idle rollers.if they stop turning then the plate is malformed and theres your answer..Si

[Setright]

For sure the paper guides in the cassettes are not centered!!!

Check them by pulling them to the middle, if they do no line up in the middle the gear/rack in the bottom has jumped. Usually because the casette has been closed to fast with a large load of paper in it.

I have also seen the guides just not placed correctly by the customer, so maybe just open the cassette again and look at the scales either side.

The sudden 5mm jump is because the edge detection sensor gives up correcting more than 5mm skew. If the guides are 3mm off center, the normal paper movement can cause it to enter the machine more than 5mm skew....

[texchar555]

just a note, I came across a 5500 and found out the ramp leading to the 2nd transfer roller was out of place. I reset the springs to the proper place and the skew went away.

[Stirton.M]

For sure the paper guides in the cassettes are not centered!!!

Check them by pulling them to the middle, if they do no line up in the middle the gear/rack in the bottom has jumped. Usually because the casette has been closed to fast with a large load of paper in it.

I have also seen the guides just not placed correctly by the customer, so maybe just open the cassette again and look at the scales either side.

The sudden 5mm jump is because the edge detection sensor gives up correcting more than 5mm skew. If the guides are 3mm off center, the normal paper movement can cause it to enter the machine more than 5mm skew....

We have permanently disabled the skew correction sensors because of that. Bit of a pain when dealing with centering the trays manually, but it works. However, if the customer never uses glossy paper, the centering sensors can remain on. It seems this only happens with gloss stock.

And you are not alone in that issue regarding the PF 601/602 units...we have a customer who refuse to listen to our cautions about this. Though we hate to do so, any time they call in for this problem, we make them wait...and wait...and wait far far longer than we would for anything else. After the 20th time or more, they need to get the point in a more direct way. It is starting to sink in. Now if only we can get them to stop feeding 300GSM 12pt stock in duplex....that alone is getting tiresome. They insist they are able to and have been doing this since day one, yet if they set the machine to the proper paper weight settings, the machine itself will restrict this. They do not get the point. This is yet another make them wait a couple days while we deal with customers who actually take our advice.

[Setright]

I find that even with gloss stock, a properly centered, and then front/back calibrated PF-602 will deliver very consistent prints. MOst are spot on, the worst have 0.5mm between front and back.

The paper's SQUARENESS is paramount! I have seen proffessionals cut paper into weak parallelograms and this REALLY confuses the edge sensor.

Measure the paper on all lengths, and check the corners for squareness.