Touch screen user interface with expanding touch locations for a reprographic machine

A touch sensitive user interface system including:

• a display screen for displaying a plurality of images representative of selectable options;
• said display screen having associated closely therewith a plurality of light source and light detector pairs arranged with respect to the display screen and defining an array of detection cells thereover, said light sources and light detector pairs arranged to detect impingement of a probe at one or more of said detection cells defined thereby, and produce a detection signal indicative of impingement and the location thereof;
• control logic, providing correspondence between one or more detection cells and selectable options, defining for each image representative of a selectable option a group of cells at which contact with the probe selects the option;
• and
• said control logic, responsive to detection of impingement at a first group of cells, expanding the number of cells in said first group having correspondence to a first selectable option, to allow selection thereof without contacting any adjacent contact areas, and upon completion of option selection, returning the expanded contact areas to said predetermined size.