Positively chargeable toner

A positively chargeable toner comprising a plurality of toner particles each containing a core, and a shell layer disposed over a surface of the core, wherein

• the shell layer contains a first resin containing at least one repeating unit having an amide group, and a second resin containing at least one repeating unit having a quaternary ammonium cation,
• in a case where a first mixture of 100 parts by mass of a standard carrier and 10 parts by mass of the toner is stirred under an environment of a temperature of 23° C. and a humidity of 60% RH using a shaker mixer, the toner attains, in the first mixture, a charge amount Q3 after stirring for 3 minutes and attains a charge amount Q30 after stirring for 30 minutes, and both relationships of “Q30≦Q3” and “20 μC/g≦Q3” are satisfied,
• in a case where a second mixture of 100 parts by mass of the standard carrier and 10 parts by mass of the toner having been charged to a saturated charge amount is born on a development roller to measure a charge amount distribution of the toner in the second mixture, an arithmetic mean X and a standard deviation Y of the charge amount distribution satisfy a relationship of “Y/X≦3.5”,
• the shell layer contains first resin particles substantially made of the first resin, and second resin particles substantially made of the second resin,
• the first resin is a copolymer of a styrene-based monomer, an acrylic acid alkyl ester monomer, and an acrylamide, and
• the second resin is a copolymer of a (meth)acryloyl group-containing quaternary ammonium compound monomer, a methacrylic acid alkyl ester monomer containing, in an ester portion thereof, an alkyl group having 1 or 2 carbon atoms, and an acrylic acid alkyl ester monomer containing, in an ester portion thereof, an alkyl group having at least 3 and no greater than 6 carbon atoms.