1940s
The modern version of ball point pen was invented by Josef (Lazlo) and
Georg Biro.
On Summer 1943 the first commercial models were made. The rights to
Lazlo's patent were bought by the British Government. The ball point pen
is more rugged than the fountain pen which may be why sales rocketed during
World War II when the Military needed robust writing implements to survive
the battlefield environment.
October 1945 The ball point pen
was introduced to the U.S. market.
The pen was sold as "The first pen to write underwater" this must have
been an unsatisfied demand as some 10,000 were sold at the launch at Gimbel's
department store in New York on October 29th 1945.