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