Heidelberg GTO -- Gearmarks on Printed sheet

[Laxmi Kant Kuthiala]

I have a double colour Heidelberg GTO. Lately the machine has started giving gear marks -- with width corresponding to the drive gears whenever I print solids or heavy screens. Have replaced ink rollers with no improvement. Can anyone suggest a solution. - Laxmi Kant Kuthiala

 

[The Heidelberg Guy]

I have a double colour Heidelberg GTO. Lately the machine has started giving gear marks -- with width corresponding to the drive gears whenever I print solids or heavy screens. Have replaced ink rollers with no improvement. Can anyone suggest a solution. - Laxmi Kant Kuthiala

Hello,

A couple of questions first, have you changed anything to do with ink, fountain solution, plates, blankets or packing thickness (thickness or number of sheets) since the time of you noticing this happening?

What king of stripes are you setting your rollers at?

It sounds as if its a bump streak, this can become more apparent with slight changes in materials, or a cam follower. Make sure that your blanket to bear height is not to exceed .001".

Tim

 

[Laxmi Kant Kuthiala]

I will check the blanket to bearer height. Which cam follower do I need to check? I have not changed anything drastic. The distance between the streaks is the same as the drive gears. Please Help!! I can't print like this. Also the same kind od streaks come in both units.

 

[The Heidelberg Guy]

I will check the blanket to bearer height. Which cam follower do I need to check? I have not changed anything drastic. The distance between the streaks is the same as the drive gears. Please Help!! I can't print like this. Also the same kind od streaks come in both units.

Unfortunatley the changes do not need to be drastic to see imperfections on the sheet. If it is actually a gear streak, there is not much you can to to be honest.

I would check all of the cam followers leading to and from the problem unit(s).

Answer these;
1) Stripe from the dampening form roller to the plate?
2) Stripe from the inking form rollers to the plate?
3) Describe to the best of your ability, what changes have occured since you started to notice this problem?

Tim

 

[Laxmi Kant Kuthiala]

The stripes are from the ink rollers. Can be seen even with the molleton damping (conventional) rollers out.
Nothing significant changed since.

 

[Laxmi Kant Kuthiala]

Hey Heidelberg Guy
I took your advice and started checking all the followers, and found 2 worn out bearings on the shaft of the gear that drives the reciprocating pump on the GTO. Will keep you informed on how it goes when we refit the machine tomorrow. Thanks for all your help.
Laxmi Kant Kuthiala

 

[Alois Senefelder]

Gear Marks

Gear Marks

Hello,

Do the marks appear on the Cylinder Bearers ( Bright Lines ) roughly half way round the Circumference of the Cylinder ??


Regards, Alois

 

[Laxmi Kant Kuthiala]

Gear Marks

Gear Marks

Hello
I am refitting the machine today. Will let you know where the marks are by tonight.
Laxmi Kant Kuthiala

 

[yaw yiadom]

mr

mr

Hi friends i had lived in england the best part of me but i decided enough is enough as an african i need to go back home and i was introduced to printing by a friend,i bought linotype herkules imagesetter and an engineer changed the floppy drive as it was faulty,it was working fine but during transit maybe liftings and that sort of,installing the machine the display panel won't lit up and darren sent me a copy of his program to try that but with no luck but i believe someone down the line could help solve this problem to make my dream come true.I'm waitiiiiiiiing

 

[Laxmi Kant Kuthiala]

Heidelberg GTO Gear Marks

Heidelberg GTO Gear Marks

I have refitted the machine but the gear marks are still there and are almost identical in both units, they are darker around the middle of a full size sheet. The distance is drive gear apart. Any more suggestions?
Laxmi Kant Kuthiala

 

[Laxmi Kant Kuthiala]

Hello,

Do the marks appear on the Cylinder Bearers ( Bright Lines ) roughly half way round the Circumference of the Cylinder ??


Regards, Alois

The marks are near the middle of the cylinder and show on the bearer. Please tell me what to do -- I desperately need help.

 

[rbailleu]

I know this is probably a mechanical issue, but have you tried a different ink or ink additives like 747 or ic compound. change blanket and reduce packing.

 

[Alois Senefelder]

Gear Marks

Gear Marks

Hello,

re Gear Marks you need the services of a qualified printing press engineer (Heidelberg)

The Plate/Blanket/ Impression Cylinders Pressures need resetting


Regards, Alois

 

[Laxmi Kant Kuthiala]

I have tried changing ink , blanket and packing but the marks remain the same. They disappear if the packing is reduced but the print quality at that level is unacceptable.

 

[Robbie]

sounds like the bearing on your main drive needs replacing....seen it before.
That explains why you have the same problem on both units. Get in a printers mechanic to check it....will sort out your problem.
p.s. the drive for the press is at the belt.

 

[Alois Senefelder]

Bearer Collision !!

Bearer Collision !!

Hello fellow Lithographers,

Please read the PDFs I posted on --- 02-06-2009


M A N bearer Collision


Regards, Alois

 

[Laxmi Kant Kuthiala]

Hello
I cannot find the PDF on Bearer Collision.
Could you please post it again or guide me on how to find it. The earliest thread I could find was on page 21 and it May 2009

 

[shajith]

gear mark

gear mark

Dear Lakshmi
first of all you must reconfirm if its a gear mark , the best way to do that is print with a screen of 70 % and you would see the lines, than move the plate cylinder by at least 1 cm circumferentialy.
then keep both the sheets together, if you see that the streeks also move by 1 cm then its not gear streak its comming form the rollers
if the streaks do not move then its from one of the bearings.
with my exprience with heidelberg GTO ,if you are having a problem with the bearings you will notice that the registration will not be correct on all the four sides it will probably be out laterally in the tail side.
regards
shajith

 

[vittamraju]

Nageshwar Rao Vittamraju

Nageshwar Rao Vittamraju

The Gear marks problem appears more while printing solid back grounds. One can avoid this by adding half circles attached to each other horizontally with minimum 25mm dia near the gripper space. This half circles should have same color percentage of the solid back ground. We successfully avoided this problem in somany jobs at our press. If this is not clear, I can send an pdf attachment with half circles to make you understand

Thanks

[email protected]

 

[vaithi47]

if it is gear marks and you are sure they come from the maindrive.check the belt for any slackness and also check all the thrust bearings ,get the help from a h'berg service engineer. if the marks from rollers check 1)all roller dia2)shore hardness3)stripe to the oscillators and plate ,stripe to pltate shold be less than the stripe to oscillator4)check all roller bearings5)change to a newwblanket with specified packing also check plate packing.5)ensure theplate is .1-.15mm above bearer and blanket is in level with bearer.6)check your ink/foutain quality.