Enbi has for many years produced a Paper Pick Roller for a global printer manufacturer for use in an office printer. However, a number of complaints from customers in the field mentioned that over time the product was not picking the paper anymore. Due to the customer complaint a joint investigation was carried out to identify the root cause and find an acceptable solution.
The pick roller was developed with a grey EPDM-45 and came through all the tests from our customer including climate tests, life tests, etc., so it was a surprise that this problem occurred. So the focus of the investigations focused on the original design assumptions and what if anything had changed since the printer went to market.
We found from our root cause analyses that the problem only occurred when the printer was not used for a long time. It was caused by a migration of low molecular excess materials that diffused out of the rubber matrix and formed a thin layer on the outside surface of the roller. This resulted in a loss of friction. There was a short time action mainly from our customer to design a repair kit that was supplied to the end users when they had problems and for long term, we needed to develop a formulation where this phenomenon could not occur anymore. As there is very little literature known, we worked together with DIK (German rubber institute) to solve this compounding issue. It resulted in a lot of testing for friction over time (6 months) in different environmental circumstances (temperature, RH, light, etc.). At the end we found a stable solution.
At the end we found a solution so our customer and also the end users were happy but the most important is that we did so much research on this topic that we are really specialists in preventing this phenomenon. We can assure at all times that our products will not cause a problem related to a long-term loss of friction.