Patents for emulsions, coating machines etc

[Emulsion]

The excellent new Google site allows very easy searching and PDF saving of patents. Here are some interesting ones that I found at a quick glance.

http://www.google.com/patents

2384657 Coating film
2411507 Ilford emulsion
1539697 Coating Film Year = 1923
370050 APPARATUS FOR COATING PHOTOGRAPHIC PAPER Year = 1887

 

[AgX]

I gave that site a try some time ago, it did no work at all.
Now it seems to be a real alternative to those other patent sites.

 

[Emulsion]

Yes, it seems superior to the US Government site as it allows searching patents pre 1970....and it allows direct saving as a PDF.

I gave that site a try some time ago, it did no work at all.
Now it seems to be a real alternative to those other patent sites.

 

[Photo Engineer]

The one patent listed, 2384657, is for an early trough coater with festoon drying. It was obsolete virtually at the time the patent issued.

A method similar to this is used at many of the older plants in Europe. The festoon rods can create defects and may therefore limit the maximum length of good coating to the floor to ceiling height in the plant.

It was a good way to get coating defects unless the entire drying area was essentially a HEPA drying cabinet with controlled humidity and temperature.

PE

 

[Emulsion]

Thanks PE. Would some of the former East European film makers still use the trough process?

Here are some more modern coating patents.

2761791 Cascade coating process
3508947 Curtain coating

 

[Photo Engineer]

I believe that some do use a modified trough coater. I think that they use a doctor blade for uniformity though which is in another patent.

PE

 

[Photo Engineer]

I checked out the two patents. Yes, I am very familiar with both of these systems. I didn't know Ted, but have met Don, the inventor of curtain coating at EK.

I typically coated 4 or 6 slide or 6 or greater curtain coatings. The hoppers used looked almost identical to those in the diagrams. One of the diagrams is a close analog of the original extrusion coater which coated one layer at a time. It was modified by an insert to allow two or more layers.

We had large felt padded boxes of varying sizes that contained cradles for the various hoppers. We put the request in with the type of hopper and width. We could choose between 4.5" up to about 12" in research and from 21" - 72" in the plant.

PE