The color formers and color developers combine upon {TAIL ~ exposure} to an imaging force, such as heat or pressure, to form different colored visible areas on {HEAD ~ the sheet} 
The color formers and color developers combine upon { TAIL ~ exposure } to an imaging force , such as heat or pressure , to form different colored visible areas on { HEAD ~ the sheet }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD