Combination ink jet pen and optical scanner head and methods of improving print quality

摘要

A housing is configured for removable insertion into a reciprocable carriage of a printer. A thermal ink jet print assembly is mounted in the housing and includes a nozzle plate for forming a plurality of ink dots on a print media adjacent to the housing. A light source is mounted in the housing for illuminating the print media adjacent to the housing. A sensor is mounted in the housing for receiving light reflected from the print media and generating electrical signals representative thereof. The combination inkjet pen and optical scanner reduces the parts count, cost and complexity associated with optical document scanning by incorporating this capability into the pen of a thermal ink jet printer. It also permits the monitoring of dot position, dot size and/or spectral information in a thermal ink jet printer in order to make nozzle firing command corrections and improve print quality during printing. Methods are also disclosed for determining whether a sheet of print media is compatible with the ink of a thermal ink jet printer and for determining the incremental paper advance distance through a thermal ink jet printer to allow adjustments that will optimally nest the print swaths.