Heat sensitive stencil sheet

A heat sensitive stencil sheet which comprises a thermoplastic resin film and a porous substrate permitting ink permeability, wherein a total of area percentages of high basis-weight areas and low basis-weight areas each having an area not less than 0.5 mm2 on the substrate is not higher than 3%,

• the high and low basis-weight areas being measured from reflected light obtained by irradiating the substrate with light,
• provided that with respect to a histogram obtained by classifying the density of a reflected light image read on an area of (10 cm)2with a 787-by-787-pixel resolution of 64 levels,
• the high basis-weight areas having a minimum density areas of (level representing a maximum peak frequency +5 levels),
• the low basis-weight areas having a maximum density areas of (level representing the maximum peak frequency−5 levels),
• and the total area percentage (%) of the high and low basis-weight areas each having an area not less than 0.5 mm2 is ((total area of the high basis-weight areas each having an area not less than 0.5 mm2+total area of the low basis-weight areas each having an area not less than 0.5 mm2)/(area of the read image)) ×100.

A heat sensitive stencil sheet which comprises a thermoplastic resin film and a porous substrate permitting ink permeability,

• wherein the substrate has a minimum dispersion index of reflected light obtained by irradiating with light of 13,
• and a total of area percentages of high basis-weight areas and low basis-weight areas each having an area not less than 0.5 MM2 on the substrate is not higher than 3%,
• provided that with respect to a histogram obtained by classifying the density of a reflected light image read on an area of (10 cm)2 with a 787-by-787-pixel resolution of 64 levels,
• the dispersion index is defined as h/(L×100) wherein h represents a maximum peak frequency in the histogram and L is (highest level which exceeds 500 frequencies in the histogram)−(lowest level which exceeds 500 frequencies in the histogram) +1, the high basis-weight areas having a minimum density areas of (level representing the maximum peak frequency +5 levels), the low basis-weight areas having a maximum density areas of (level representing the maximum peak frequency−5 levels ), and the total area percentage (%) of the high and low basis-weight areas each having an area not less than 0.5 mm2 is {(total area of the high basis-weight areas each having an area not less than 0.5 mm2 +total area of the low basis-weight areas each having an area not less than 0.5 mm2)/(area of the read image)}×100.