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I have a couple of Olivetti Logos calculators such as 42PD, 45PD (on the picture) and 75S. These all have a common dot matrix printer of a reliable electro-mechanical design. The only problem that I have encountered is that the platen gets hard and stiff such that the paper is not fed properly - see the picture. The paper runs via the platen and is clamped towards the platen by a relatively small metal counter-wheel that is resiliently biased towards the platen from the underside. The paper now slips between the counter-wheel and the platen. I have tried to rug the platen and the counter-wheel with a fine paper, and have tried to soak the platen with brake fluid that I read could be used for typewriter platens that have gotten stiff. After the brake fluid treatment, the printer worked OK for a while, but after a while it was back to its initial bad paper feed. Anyone has any suggestion how to counteract this problem?

Best regards Jonas
Have you tried any of the made-for-purpose platen cleaner/restorer products? I've used some on the sheet feeder of a HP scanner (actually a combined laser printer/scanner/fax) that wasn't picking up the sheets properly and it worked a treat.
One product I've used for rubber rollers in paper drives is:

CaiKleen RBR Rubber Cleaner & Rejuvenator manufacutred by CAIG Laboratories

You can get it on, you know, that auction place via buy it now. Don't recall the price but it was not overly expensive.
Here is some:


I agree this stuff works far better than you might expect on rubber rollers that are drying and losing their grip, but I've never tried it on rubber rollers that have fully hardened over 30-40 years. It may work though and is probably worth a try as it lets you avoid trying to track down replacement, which is hard and never cheap.

If you try this, please do let us know how well it worked out.
Thanks for all kind suggestions, I will try and come back to you with the result.
best regards

I ordered the CaiKleen RBR Rubber Cleaner & Rejuvenator and put in on the platen for 24 hours. Afterwards I wiped the platen and it then worked much better. I waited a couple of days, and it still seems to work fine, see picture. Thanks, I will now test on the other Logos printers I have.

Best regards

Thanks very much for confirming your positive results here Jonas. It's good to know that rubber rejuvenator works well even on extremely old/hard rollers.
All my Olivetti Logos machines' printers work much better now when the platens have been treated with the CaiKleen RBR Rubber Cleaner & Rejuvenator. Of all the different remedies I have tried, this is by far the best. I enclose a photo of the 75S together with some distant relatives in the form of technical calculators with a printer, or connectable to a printer.
Best regards
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