GTO 52 Registration problem.

Hi guys,

I have a single colour gto 52 in which I am feeding A4 size printer paper.

I am trying to check the registration of the press,

I printed 100 sheets then re-fed them in.
at first the print was not lining up so I adjusted the sheet advance knob until I had accurate registration.

Now I find that every 10 or so sheets the next sheet is completely out of line, the main problem being the sheet has moved sideways, anything from 1/2mm to 10mm.

Could anyone please give me some input on what might be causing this?

Any help would be appreciated!
Thanks in advance!

 

Hi you should be able to feed the sheet in second time round without adjusting anything how olds your gto?
when you said you are adjusting your sheet advance knob do you mean your front lays?
a couple of things that would cause this are the centre lay not being wound right to max
make sure your side lay height is set to the right stock
if your infeed grippers are worn you may be getting either to little drop or to much drop on the sheet

 

Hi, Thanks for the reply.
Its a 1993 GTO 52 with around 35mil.
By sheet advance knob, I am relating to the large adjustment knob under the lever which controls whether the side lay will push from the left or right side. It is marked with a scale up to 1.2mm, forwards and backwards,

The front lays are set up so only two on each end are in contact with the sheet, I do not think the infeed grippers are worn as movement is sideways rather then vertical.

 

then you need to just set the height of your side lay on the thumb screw do it so that you can just get two sheets under the lay that should do it

 

Hi,
I adjusted the height of the side lay, it made an improvement but the image is still moving and i am not getting a constant register!

The large knob under the selector lever for the side lay, could you please tell me the exact function of this as so far I have only guessed it to be the sheet advance timing.
Thanks!

 

The large knob under the side guide selector on the drive side is micro adjustment of the side guide. There is no such thing as sheet advance on GTO with single sheet feeder. If you are having side register issues I would think there is an issue with movement of the side guide. If you have having side register issues that are 10mm off you should be able to see this just by watching the sheet come down the feed board. Is the sheet hitting the side guide? Are you using sheet smoothers? Is the swing gripper hitting the sheet on its way back to the feed board? The sheet should flow smoothly down the feed board and into the press. Make sure all headstops are moved all the way forward and the outermost headstops all the way back. Also you can check your sheet drop. Make sure the traveling grippers are releasing the sheet 1mm before it gets to the headstops with the outermost headstops at gripper bite minimum. Also try switching side guides or no side guides at all and see if the sheet flows smoother down the feed board.

 

Like exheidmech said the knob on the side is just micro adjustment. If you are not getting any front to back mis register then it can only be either static on the table or the sheet is catching something on the table try putting your lays on max grip and see if this makes a difference

 

Thank you exheidmech and LLS for the feedback to date.

I will check all settings again and wipe the board for static.

But could you tell me how to adjust the traveling grippers so they release the sheet 1mm before it hits the front lays?
I cant seem to find any adjustment screws for it,
Thanks

 

it is not a job I would suggest you try yourself but like I said if you dont have any mis register front to back it not going to be your feeder grippers

 

Its actually not a horribly difficult adjustment to make. First you need to look under the feed board. You will see a long arm that pivots in the middle. At each end of the arm is a small block. These two blocks contact the cam follower on the traveling grippers to open and close them. The block you are concerned with is the one closest tot he head stops. You will find a 3mm allen at the bottom of the block, this is your adjustment screw. You must loosen the 13mm bolts to make this adjustment. To check what your sheet drop is follow this procedure. Remove all sheet smoothers. Open the side guides to their widest position. Make sure the 2 outermost headstops are at gripper bite minimum for the sheet size you will be using. Have the press pick up a sheet off the pile and allow the press to carry it part way down the feed board. Stop the press a few inches before this sheet gets to the head stops. It is best now to turn the machine by hand. Move the machine in the forward direction while applying slight downward pressure on the tail of the sheet (this will likely take two people). At some point the sheet will stop moving because the grippers have released the sheet. Use a pencil to make the position of the tail of the sheet on the feed board. Now let go of the sheet and place it against the headstops. Again use a pencil to make the position of the tail of the sheet on the feed board. These two pencil marks should be 1mm appart. If they are too close, loosen the 13mm bolts and turn the 3mm allen clockwise. If they are too far appart, loosen the 13mm bolts and turn the 3mm allen counter clockwise.

 

well explained its easy for us guys tho because we have done it loads but he might cause himself more headaches by doing it if not set up right for the sake of getting someone out local that could sort it within half an hour just a thought

 

Thanks for the detailed instructions.
I will use your method for checking on the feed board the exact point where the sheet is being released before I determine if I need to make any adjustments.
Up to now I have managed to set the machine up so that I get accurate side lay registration but out of a 100 prints I get about 3 or 4 sheets which have mis-registered by up to 1mm. I do not know if this level of error is acceptable but I am very disapointed as the gto 52 is supposed to have very accurate register every time and feel I may have to just live with this amount of error for the time being.

but my question is, if any of you know any serviceable parts for the side lay mechanism that I should replace to fix this? I know there is a side lay spring available (not for the selector lever but for a mechanism under the panel) and I am considering buying this as it is only 20 pounds but in your opinion would it make any difference? is it common for the spring to loose its tension and thus causing play and affect the amount of side lay push? or would I still need to work on my paper feeding? as mentioned before i am working with 80gsm a4 paper which is being fed portrait ways.

 

I would always try and run the paper landscape as it less likely to kick around you used to be able to get extended side lay parts for running portrait but no one really ever run it that way especially on 80gsm as for the spring that will only cause you problems if it snaps