slurring issue on MOVP

Having a slurring issue on first two units from front to back.... happens on all stocks.. can someone please help.... im stummped

 

Did you checked the cam followers on impression cylinders?

 

Are the first two units running, fitting and registering together but slur going into the third unit? Printing perfect or straight? More info would help troubleshooting.

 

the last two units register together on the sheet. the first two units move, not always together, back and to the left on the o.s. On the sheet it looks like the image is doubling on the back right hand side of the sheet. it shows on the slur in the color bar. when u bring the press up to speed it registers better but still moves in the first 2 units. the lighter the stock the worse.
I checked the gripper fingers on the impression cylinder and didnt find any that were sticking, the cam followers also look fine.

 

Have you determined it is not being caused by side guide? Try running sheets w/o guide. Recent jam up at feed board? Kind of thinking sheet distortion rather than loss of sheet in transfer, but not seeing sheets, can' t say for sure. Is it just the corner that's slurring?

 

still happens w/o guide. about 3/4 of the sheet is out of register only for 5-10 sheets and then will print in register for a couple of sheets. its very random when it goes out of register. holds register better when u back off the blankets but its not enough pressure to print. even then it moves some but not as much. ive tried to set the feed board tight on the sheet and loose, ran with brushes and with out.

 

Now sounds like combination of loosing sheet due to lack of gripper pressure and tack influence. Does it seem worse at start up, after press has say idle a bit? Cam followers were inspected, but did you lift them off the cams to be sure? Conv or alcolor? Conv are notorious for overspill and leak of water, any signs of rust at any of the gripper shaft pillow blocks?

 

yes it is worse at start up when running lower speed, when u speed up to 6000 iph it comes in to register. i tried to reduce the ink but it did not matter. has the alcolor. i did not lift the cam followers off the cams so i will try that on monday. i did not see any rust but the press is far from clean. it has 98.5 mil impressions.

 

sounds like impression cylinder grippers need to be adjusted

 

hey spike, is that difficult to do, special tool required? could it be the pad is worn out?

 

Ft Walton - if the problem just started all of a sudden, it's not likely individual gripper settings. If you've seen it coming on gradually over the months, then it's likely. If your MO is older than about a 1989 (approx), then your gripper fingers will have, or used to have, a urethane coating on the tip. If that's the case, and your urethanes are gone, no amount of gripper settings will help much. Setting of grippers is not possible without special tooling. Do look closely at your followers and gripper bar shafts before you start thinking grippers.

 

the pads could very well be worn and you should be ablle to see if they are/ to set grippers the press has to be at the
correct degree and correct gauge needs to be used consult your mechanic or manual /you might be able to obtain that
info here somewhere

 

i have checked the cam followers, lifted them off the cam checked the bearing, they lift nicely and smooth. looked at the pillow blocks and see no signs of any rust or water in the grease. the only thing i can see is a substantial amount of build up of ink on the bearers of the impression cylinder

 

Try running sheets into press(impression not necessary), stop press with sheets in, and pull on tail of sheet as it is in transfer at suspected unit/cylinder. Kind of hokey way to go about it but may indicate what bar is causing loss of sheet. You should not be able to pull sheet out of grippers at any point of sheet travel

 

well i tried that mqg, and i can pull the sheet out of all double transfer cylinders and not the impression cylinders. i ran 218 gsm paper through. the grippers seem snug but i dont have to yank hard to get the paper cleanly out

 

try lifting each individual gripper and clean behind them and clean the pads as well.
also try a piece of thin stock paper as a feeler under each impression cylinder gripper if it just slips out on one side then it more than likely your gripper shaft has collapsed.

 

Not unusual to be able to pull sheets out of double transfers as the spring pressure is far less than at impression and first trx

 

thinking it may be packing.... grippers on impression cylinders and 1st and 3rd transfer are ok... i will post later if i solve this issue... thanks mqg and all who helped

 

Thank you for everyones input, the problem was the packing in the plate and blanket cylinders along with worn blankets...
guess my pressman didnt know what he was doing... funny thing was that all the cylinders on the press are at different heights so i had to pack them all differently to get the correct fit...

 

ok i was wrong, i ran a job on 100# cover and it printed fine with no movement, went to 80# txt and it wont hold register. Anyone??????????????????????????