Who invented offset printing ink?

Though printing ink has been around for thousands of years, it is generally accepted that Ira Rubel of Nutley, New Jersey was the inventor.  

While printing on a printing press with conventional oil based inks, he noticed that when a sheet was missed, the plate left an image on the rubber impression cylinder. When another sheet was passed, the rubber impression was better than the one from the plate!

So in 1903 Rubel made what is accepted today as the very first offset printing press that duplicated this error. 

The ink for this offset press was formulated and refined during the years 1903 to 1905 as it was operated in his printing factory. This is believed to be the first real use of ink used and designed for offset printing.  

Formulas continued to be refined as the offset printing process gained momentum.