Individual sheet feeder device for printer

Claim 1

A sheet feeder accessory device for feeding manually inserted pre-printed forms to a print point in a printer having a predetermined feed direction, comprising: a sheet feed guide structure for guiding a manually-inserted pre-printed form to be printed into the printer; mounting means for removably attaching said sheet feed guide structure to the printer; sensing means comprising at least two optical position sensors arranged in said sheet feed guide structure in mutually differing spaced relationships prior to the print point in the printer in said predetermined feed direction for selectively performing a sequence of detection of at least a desired one of the features including: a leading edge of the pre-printed form to be printed; a trailing edge of the pre-printed form to be printed; and at least one registration mark contained within the pre-printed form to be printed; said at least two optical position sensors comprising means for generating at least two detection signals in response to said sequence of detection of said at least one desired feature; a control processor operatively connected to each of said at least two optical position sensors for receiving each said at least one detection signal; said control processor comprising means for performing an evaluation of each received detection signal in relation to at least one predeterminate print field of the pre-printed form to be printed; said control processor comprising means for generating in response to said performed evaluation at least one first control signal for transmission to the printer for causing the printer to automatically advance the pre-printed form to be printed by a predeterminate amount corresponding to a location of said at least one predeterminate print field; and said control processor comprising means for generating in response to said performed evaluation at least one second control signal for transmission to the printer for causing the printer to accept data for printing.