Jerry Shinaut
Quality Assurance Manager
The (Phoenix) Arizona Republic

A Just a little background on how this new sequence came about. I was working with Goss engineers at The Orlando (Fla.) Sentinel. We were trying to reduce the ink buildup on the Goss keyless dampener form roller. At startup, the ink would cause the roller to slip instead of transferring dampener solution to the plate cylinder. As a result, cleanup was very slow at the lower press speeds.

We tried a number of ideas, but the one that worked best was to simply run the dampener form roller in contact with the plate cylinder for a short period of time. This helped to clean the roller of the ink buildup. When the dampener system was turned on, cleanup was within a few revolutions. As a further protection toward keeping the roller clean, we also altered the press shut-down sequence. In this case the water form roller was left in contact with the plate cylinder until the impressions came off.

PRESS START-UP

 Impression on 0 seconds

Dampener forms on 0 seconds

Dampener spray system on 2 seconds

Automatic flood duration 5 seconds

Ink forms on 4 seconds

Inking system on 6 seconds

 Inking system off 0 seconds

Ink forms off 2 seconds

Dampener systems off 4 seconds

Dampener forms off 7 seconds

Impression off 7 seconds

 Using this information, I went ahead and altered the Colorliner start-up and shut-down sequence at The Seattle Times and The New York Times. Very good results were achieved. The cleanup at startup was very fast and I was able to reduce the automatic flood to five seconds. When I had an opportunity to work on a Colorliner press at the Tennessean, Jacob Lynn of Ryco was there to review the installation of his dampener bars. We had equally good results, and I am now sure that Ryco recommends the same changes.

The only difference I see between our recommendations is the turn-on times for the inking system and form roller. To be consistent, I can agree with Lynn’s recommendations. During testing you need to see if the some of these times can be changed to obtain better results as some local press conditions may influence your actions. Jerry, by the way, I consider The (Phoenix) Arizona Republic quality program one of the best in the country. Keep up the good work.

Q Follow up to Bob Warner’s question about blanket linting problems on press (Newspapers & Technology, July 2000).

Wilson Cunningham
Group Project Coordinator
Gannett Offset

A I have seen the type of linting described by Bob Warner on three different occasions. Each time the problem worked its way back to the newsprint. Generally the scenario involves an imbalance in the newsprint’s chemical composition because of the presence of recycled fiber, de-inking soaps and retention aids.

Because of manufacturing changes, generally trying a new product or a change in process pH, soap-like material will transfer from the newsprint and embed on the blanket. It appears like paper linting, but it is really a soap film with paper fiber attached. Generally you will find the problem more prevalent on one side of the sheet. Increasing water setting (often shows up on the next plate after a dummy plate or after a plate requiring limited ink coverage) seems to make it worst. Not being able to clean the blanket to the base rubber is one indication that a soap film is the causing the problem. A latent image will remain visible even after cleaning with the most aggressive solvents.

In one case, I found the problem to give the wavy lint pattern but the soap was depositing on the plate. Localized non-image area became partially ink-sensitive and a random width and length would tone “print” in the direction of the cylinder’s rotation. Finally, if the lint can be peeled off the blanket like a sheet of paper, deposition of a soap material is highly likely.