3 na 2 so 4 mgso 4 k 3 po 4 and na 3 po 4 alkylamine salt alkyltrimethylammonium halide alkyldimethylbenzylammonium halide alkylpyridinium halide alkylamidemethylammonuium halide alkyloxymethylpyridinium halide and polyoxyethylene alkylamine as commercially available cationic surface active agent for example polyethyleneimine 210t made by sogo pharmaceutical co ltd can be employed soaps such as potassium oleate turkey red oil oleic acid isobutyl amide sodium salts and amine salts of higher alcohol sulfuric esters polyethylene glycol sulfuric ester fatty acid amide sulfuric ester olefin sulfuric ester alkylsulfosuccinic acid salt alkylarylsulfonic acid salt alkylphosphate and alkylphosphonate glycerin polyoxyethylene alkyl ether polyoxyethylene alkyl phenol ether polyoxyethylene alkyl ester polyoxyethylene alkylamine polyoxyethylene alkylamide sorbitan alkyl ester and polyoxyethylene sorbitan alkyl ester salts of alkylamines and monochloroacetic acid salts of alkylamines and sulfuric acid salts of alkylamines and sulfonic acid and salts of alkylamines and phosphoric ester the above components can be employed alone or in combination when these components are applied to the surface of the recording layer it is necessary that the surface of the recording layer be studded with these components in other words it is necessary that these components be scattered on the surface of the recording layer in a minutely discontinuous state that is in the form of dots over the surface of the recording layer however it is not necessary that each of the scattered components have a particular shape representative examples of a method of performing such application of the above components in the above mentioned manner are as follows 1 applying the above components in a dry state to the recording layer by bringing the components into contact with the recording layer followed by rubbing the components against.