Agfa Proset 9400 capstan getting "sticky" and "whitish"

[anfrmite]

Good day to everyone,

I know... it is a 30-old year machine (but still is my favorite in my workshop).

It was with crisp definition and aligment until late 2019 (no slippery or jam film issues that I could recall in all his whole life). Then, starting 2020 we switched to test a Linotronic we had in the basement, and put to a well-deserved temporary rest the old-reliable Agfa Proset 9400.

But today, after more than 18 months without operating, I take a look at the Proset 9400 and -to my surprise- I notice that the capstan roller (yes, the most important part of a capstan-imagesetter!) has a whitish coloration all over it, like if it was impregnated with white heat-sink grease or some kind of paint. If i touch some part of the capstan, it feels sticky, and by gently passing a finger over it, the withish and sticky falls like an eraser residue (similar to when you erase some pencil text over paper). Underneath, the black surface of the capstan roller appears ok.

Attached are two pictures of it (the second showing more detail of the capstan roller surface).

What happened? Is this the end of the capstan roller? It is only dirty? Could I try to clean it?

The precision of the diameter of the capstan roller is so critical that I believe that if I intend to clean it to expose the black surface (that appears ok) under the withish residue, the imagesetter could get ruined for spare-parts only.

Any advice? Have someone seen similar cases?

Thank you very much for any help in advance.

Regards.

 

[Puch]

The rubber surface of the capstan reached it's end of life. With continuous use it might be postponed - as in your case - but when it's tossed away for a while, the plastic starts to disintegrate eventually. I had the same issue with an old printers' rollers. The solution was to exchange all the rollers.

In your case it might prove to be difficult, knowing the device's age. AGFA might have a spare somewhere in a warehouse's last room. If you can't get a replacement, I would try to find a company which does roller-refurbishement. Here we have several companies doing this for printing machines. They renew the rollers of the ink feeder system of Heidelberg and other printing machines, to very tight tolerances. If you find a similar company, they might help you.

 

[anfrmite]

Puch,

Thank you for your reply.

Yes, it appears as you stated (because of no using it for a long time).

I also have seen that -as you stated- in many old laser printers. However, in this particular case, the rubber appears as not enitrely desintegrating in small crumbs. That is, when I gently take apart the whitish layer, a very uniform rubber roller surface is showing. Of course, I am not sure about that. It should be necessary to take apart the capstan roller and take measurements with a micrometer to verify the diameter to compare it with the calculated diameter specified in the Agfa 9400 Service Manual -which I have- and from which the calculation can be made involving Pi, diameter, and the specified driven increments for motor step (the Acusset Service Manual is more direct than the Proset and they state the exact diameter of the capstan, without any calculation needs).

Regarding your advice about precision roller-refurbishment, I have done it in the past for my roller laminators, so it is no problem to me. I just wish to hear wise-advice (like you) so that I am not feel so crazy to try that route with an older machine like this, but believe me, I really prefer this workhorse over other newer machines!

I cannot think about a newer direct-to-plate alternative, because for my process (metal etching) only the transmitting-light film technology is available. Also, upgrading to a bigger-film area is not any benefit to me also, because the work-area is dictated for the subsecuent machines in my process.

Since I need to take apart the capstan to take micro-measurements of it, I have nothing to loose trying to cleaning it and then run test jobs to see the loss of precision after cleaning -or the totally slippery issues that I may encounter.

Thank you for your time and reply!

 

[Puch]

I wish you good luck with the cleaning. I've been using these machines from 1990 until 2007, ProSet 9400, 9800, then a 9550. Well-built, dependable devices with minimal hassle. Nice to hear that they're still working somewhere.