The use of microfilm records in conjunction with statistical cards has been ever increasing in recent years. Various means have been devised in the past for reproducing such microfilm records without removing them from the statistical card. However, an improved means has been sought permitting the inexpensive reproduction of the microfilm record contained in the statistical card and of indicia placed on the card in pencil, in ink or typewritten.
One prior-art structure requires that the entire statistical card be formed from a transparentized, reproducible material, and the entire card is reproduced along with the microfilm record contained therein. This method, however, is not always desirable and can be very costly. This invention provides a means of indexing microfilm records in a reproducible manner without incurring great cost.
USPTO Backgrounds
USPTO Backgrounds