Optical sensor for ink jet printing system

An ink jet printing system for printing ink jet images on printing media residing in a media plane, the system comprising:

• a printer frame;
• a media transport connected to the frame and operable to move a sheet of media within a media plane along a feed axis;
• a carriage connected to the frame and movable along a scan axis adjacent to the media plane and perpendicular to the feed axis;
• an ink jet print head mounted to the carriage;
• an optical sensor module connected to the carriage, the sensor module comprising:
• a chassis;
• an illumination source connected to the chassis and spaced apart from the media plane;
• a detector connected to the chassis and spaced apart from the media plane;
• an integral optical element positioned between the media plane and the illumination source, and positioned between the image plane and the detector;
• the optical element including a first portion having a first optical characteristic positioned on a first optical path between the illumination source and a selected region of the media plane;
• and
• the optical element including a second portion having a second optical characteristic different from the first optical characteristic and positioned on a second optical path between the illumination source and the selected region of the media plane.

A method of analyzing a printed image on a sheet of media, the method comprising:

• generating a beam of light;
• directing the beam of light to a selected region of the sheet;
• focusing the beam to a limited area at the selected region;
• scrambling the beam to provide uniform illumination of the selected region;
• and
• measuring light reflected from the selected region to determine characteristics of the printed image in the selected region.