An image forming apparatus includes an image carrier which carries an image and a transfer roller including a roller base material which faces the image carrier and rotates. The operands include first and second floating point numbers having first and second mantissas, respectively, the second operand greater than the first operand. Images of the same blurring direction are selected and grouped from the image of a plurality of frames based on that judgment result. In addition, the cone clutch is described that blocks the power transmission from the wind vane and the impeller in case of strong gusts or wind. Uniform wettability further stabilizes bonding and improves bonding strength of the speaker diaphragm onto the voice coil and edge, offering a speaker with improved input power durability. In the second step, second voltage is applied between the semiconductor member and the electrode member constituting the memory cell belonging to the second group.