Brooke Engineering Professional Photo Printer 

Brooke Engineering is a Seattle area company that has a niche in making expensive, professional photo printing equipment. They make a line of cutters that can take a roll of 8x10 color printers and slice them very nicely all automatically. In 1991 I did some mechanical design work for them while I was self-employed.

They also make a printer ("enlarger") that is designed to make a print from a negative onto photo paper. Not much different from your ordinary enlarger any photographer might have, except this one could print on a continuous roll of photo paper and from the same negative, make an 11x14 print followed by two 8x10s followed by a sheet of wallet sized, etc.

It did this by means of a very clever design Mr. Brooke came up with. Inside the enlarger were a series of lens assemblies stacked up one on top of the other. Each assembly was a large (24 x 36") aluminum plate with two sets of moveable lenses on top of the plate. Each set of lenses could be moved out into the light path by pneumatic cylinders to set the enlarger up for a particular photo format. By having the lens assemblies arranged properly and pre-adjusted, the machine could simply slide out the right lens assembly into the light path and as fast as you could say "cheese", it would make a print of the desired size.

What I did for Brooke was to redesign the lens plate assemblies so they could handle lens and cylinders on the bottom as well as the top and to redesign his shutter mechanism to use a rotary solenoid to improve performance and cut cost. His goal was to take his existing system and add several more enlargement sizes he could handle by adding one or two more lens assemblies.

This was pretty interesting as I had never used pneumatic systems before. His enlarger system this went into had a built in air pump and was quite large - the system was as large as two big refrigerators side by side.

Here are some of the drawings I produced for the product. Click on any of the images to see a bigger version:

This drawing is a front view of the lens carriage assembly. The various lens plate assemblies would be placed in a particular slot depending upon the particular lenses and what enlargement options the customer ordered. The assembly Bill Of Materials was obviously quite long as there were many permutations the customer could choose from when ordering the system. In this drawing, the plane of the paper is down at the bottom of the page while the film negative plane and shutter is up at the top. You can see two lens plate assemblies in this drawing - one at the top and one at the bottom.

This drawing is a plan view of a typical lens plate assembly. You can see the pneumatic cylinders and tubing. Also you can see the two lens plates with the large rectangular holes in them.

Last updated: November 09, 1996