Method for making a heat-sensitive stencil

A method of making a stencil by thermally forming perforations arranged in both a main scanning direction and a sub-scanning direction in a thermoplastic resin film of heat-sensitive stencil material by the use of a heat source which is heated through a supply of energy, the method comprising the steps of:

• cutting the supply of energy to the heat source when a time interval not shorter than 50% and not longer than 100% of an estimated perforating time lapses from the time at which the supply of energy to the heat source is started, the estimated perforating time being a time interval expected to be necessary for a perforation to be produced by the heat of the heat source and to be enlarged to a desired final size, the time interval of the estimated perforating time being measured from the time at which the supply of energy to the heat source is started,
• in which the estimated perforating time is set to be a time t2 represented by formula B A ⁢ ⁢ exp ⁡ ( Ct 2 ) = 4 100 ,
• when a graph of the diameter of the perforation against the time from the time at which supply of energy to the heat source is started, is regressed on an exponential function A - B exp ⁡ ( Ct ) ,
• wherein A, B and C are positive constants.