There's also a Local Printer Setting Utility program available (free) that lets you set all parameters, even things like toner density, contrast, fine line enhancement, etc.
At 09:48 AM 7/19/2014, you wrote:
Trying to get the local Makerspace interested in the project.
Lexmark printers can really lay down heavy ink. I've had good luck doing iron on toner transfer boards with my 4039 10+.