HP INDIGO 5000 paper jam in the blanket

Hello guys, I have an issue with paper jam in the blanket I figured out that's the paper in the blanket or in the top of the duplex doesn't have the gripper edge so I suspect the timing. I did the fallowing :
encoder calibration (one things there's 2 holes in the impression drum one is silver and one is dark with grove )
I did use the silver hole because it makes sense when calibration the encoder in the value zero the gripper side match the blanket side.
but I still have the jam. I notice one thing when I push the inshing switch the drums turn and the stop station engage the gripper are open . ( in my case the gripper remain open (normal way the gripper should close after the stop station release . ( it should close ). another thing is when i rotate the hand wheel manually the gripper should remain close but it is open .so i go to the cam follower and snapped to finish the cycle manually than the ripper close
i checked the spring for the dummy cam follower they are fine
Any idea why it keeps jamming?

 

I did change the gripper assembly still have same issue

 

Hi, I know you have done a couple of things and you have good knowledge of your press, so I will try to suggest just a couple of things more. Take in consideration I've only operated the 5500 and 5600 of series 2 so I don't know if some of the following elements are present in the 5000

1- First off, have you checked the Input Feed Roller sensor? Some time the brackets that hold this sensor will break so the sensor won't read the presence of the paper as it should.
2- The input feed roller assembly has a plastic coupling that may break with time, so you will need to changed, it happened to me the last month for the first time and the paper was stucking on blanket or in the bridge
3- You said you did a encoder calibration, ok... there is a considerable hole located near the carbon brushes in the operator side, where you can see the teeth of the impression drum and the ITM drum, when you see through this hole you should see that both drums have some red points that need to be aligned each other, if they are not, you will have problems. So you will need to align them
4- About the grippers remaining open, yes they should close at certain angles but it is normal that some times they still open, so it's ok if you close them manually
5- About the stop stations, if your problem is on the paper entry, then we could suspect a problem with the entry stop station, if you haven't dismounted them, would you do it and inspect they look in good state and not broken, also switch positions and try a new paper transport
6- And the last you may try to tweak the timing on the Diagnostics>Substrate>Input feed section

I hope any of these steps may help you,

 

Finally fixed by replacing the encoder ,it was timing problem ,now i can run the paper true and duplex too,the only issue i still have is i have to bypass thr gripper sensor ( it jam when i don't bypassed sometimes)
the sensors work fine .thank you for the help