Impression problems on Hamada 500 CDA

Hi Everyone
Having 1 or 2 problems with the 3rd sheet coming off the press looking like theres not enough impression pressure so some images mainly the front edge are fainter then the rest of the sheet do you think this could be the main cylinder bearings (my worst nightmare cost wise) I would imagine all sheets would look rubblish if the bearings have worn, I have changed the lower form roller for new and have the upper form roller to go in but need to press the bearing in a bit more before I can fit so only running 1 new form at the moment. Anything else I've forgotten? Have checked roller and impression plate to blanket blanket to impression cylinder pressure already and it seems fine good even strip. Any ideas would be much appreciated, thanks Allan
 

chock

Well-known member
Hi sir:

please check the paralell between upper/low feed Rollers.

2) Overall pressure between upper/low feed Roller

3)impression drive lever/detent pawl clearance

4) Cam band

5) Ductor ink roller pressure

6)Form/Roller/Plate cylinder pressure

7) Plate/Blanket cylinders pressure(parallelling)

8)Blanket/Impression Cylinders pressure ( parallelling)

9) Form Roller/Plate cylinder pressure

Blessing
superchock@yandex.com
Mobile+WhatsApp:+505 8861 1441

Managua, Nicaragua
 
Hi Chock Many thanks for you advice there sure is a fair bit there to go through so fingers crossed I may find the problem.
Thank you for the info, have a great Xmas Allan (uk)
 
SOLVED it turns out the impression cylinder is worn (the press is 25yrs + years old) increasing the thumb screw for the impression to max has solved the problem, I was so convinced it was the main bearings that I missed the obvious, just wondering if I could file the slot where the thumb screw is to get a bit more adjustment? Because when it wears next time I have no adjustment left. I suppose this is not a good idea but who knows. Hope this may help someone.
 

Magnus59

Well-known member
SOLVED it turns out the impression cylinder is worn (the press is 25yrs + years old) increasing the thumb screw for the impression to max has solved the problem, I was so convinced it was the main bearings that I missed the obvious, just wondering if I could file the slot where the thumb screw is to get a bit more adjustment? Because when it wears next time I have no adjustment left. I suppose this is not a good idea but who knows. Hope this may help someone.
Are you sure the impression cylinder is worn, even on a 25 year old press it would be unlikely, the bearers may have some wear, but not the cylinder itself.
It is more likely that the blankets are a different thickness than you have used previously and need extra packing.
 

bill kahny

Well-known member
I don't think a problem on just every third sheet would be the press. I would suspect bad paper. The convertor uses multiple rolls collated and slit to made a carton of paper. Please try better and totally different stock. Bearing down on the cylinder may compensate but don't the other two sheets look squeezed?
 

SteveSuffRIT

Well-known member
I don't think a problem on just every third sheet would be the press. I would suspect bad paper. The convertor uses multiple rolls collated and slit to made a carton of paper. Please try better and totally different stock. Bearing down on the cylinder may compensate but don't the other two sheets look squeezed?
If the defect is every 3rd sheet, separate and remove that 3rd sht, many times.
Print using that new sorted stack of paper.
If the defect is gone, then its the paper.
If the defect continues, then its the press.
I don't think most duplicators have bearers on plate & blanket cylinders.
Back cylinder (Impression) never has bearers, it has to move in/out to compensate for different paper thickness.
 

felixkinn

Member
Hi Everyone
Having 1 or 2 problems with the 3rd sheet coming off the press looking like theres not enough impression pressure so some images mainly the front edge are fainter then the rest of the sheet do you think this could be the main cylinder bearings (my worst nightmare cost wise) I would imagine all sheets would look rubblish if the bearings have worn, I have changed the lower form roller for new and have the upper form roller to go in but need to press the bearing in a bit more before I can fit so only running 1 new form at the moment. Anything else I've forgotten? Have checked roller and impression plate to blanket blanket to impression cylinder pressure already and it seems fine good even strip. Any ideas would be much appreciated, thanks Allan
I am also facing these problems.
 

De-Inking

Avanti
Sustainable Printing Goes Far Beyond Using FSC Certified or Recycled Paper
This informative paper on deinking: demand, principles, problems and solutions also explains why printing technologies are not all equally compatible with paper recycling systems; and why just a small fraction of printed material in the paper can cause difficulties.
Link To White Paper

   
Top