Komori 528 impression problem

Yesterday we replace the plastic gear in the 4th unit for the water metering unit as the gear was starting to chip. Today, the 4th unit isn't fully going on impression.
Damps & inkers coming down on time, but unit not going fully on impression,
No errors in relay panels. All lights indicate impression. Took off gear side cover and saw shaft marked #4 not fully rotating on impression.

Any thoughts?

Mike

 

First question for a 28 inch impression problem is what type of impression you have. Is it the older eccentric style or the newer impression motor? I'm going to guess that it is the older eccentric and based upon that, there is a small air cylinder on the operator side that moves a small cog. This starts the whole impression process that requires roughly two rotations of the cylinder. I would recommend opening up the operator side unit cover of an adjoining unit and watching the process. You can then identify the small air piston, that puts the unit on impression, by pressing the Imp push button on/off with the press stopped. Look for movement on the good unit and then compare that to the bad 4th unit. Then do the same with the press on crawl. You are looking for a difference between the good unit and the bad 4th unit. Usually the problem on 28's are the small air cylinder but because of recent work on the same unit, anything is possible. Keep your fingers out of the moving press!

 

Komori

Thanks for your help. We had the press running over the weekend and the unit was back going on impression. Pressman told me this had happened approx. 4 years ago.
One day wouldn't go on impression, the next everything was OK.

We'll see what today brings.

Mike

 

Glad to hear it. I was going to say that there's no way that changing a nylon gear on a Metering Roller can affect the impression on a printing unit. Doesn't matter if it's the same unit or not. It's like changing a tire on a car and then wondering why it suddenly won't start.

Printing can be complicated at times but it's rarely ever rocket science. Common sense almost always prevails.

 

Komori

I couldn't see how changing the gear would affect the impression either. Just another coincidence of printing.

Appreciate the info & suggestions,

Mike