Abstract: A laser beam 21 outputted by a laser oscillator 3 is collected by a machining head 4, so that the surface of a roller 2 is irradiated with the laser beam. An encoder 5c outputs a signal in accordance with a rotational position of the roller 2. A control portion 24 controls the laser oscillator 3 to irradiate the roller 2 at the same spots on the surface with the laser beam 21 per rotation of the roller 2, the irradiation being repeated a plurality of times, thereby forming recesses in the surface of the roller.

Abstract: A battery which realizes high power output, cost reduction and increase in capacity. An enlarged port section is formed in an open end of a battery case. A ring-shaped support rack section is formed inside of the enlarged port section, and a ring-shaped insulating gasket is set on and supported by the support rack section. The battery has a collector of one pole, to which an end portion of an electrode plate of one pole protruding from an electrode plate group is connected. A ring and flange-shaped collar section, which is tiered with a step, is provided in the periphery of the collector, and the flange-shaped collar section is set on the bottom face of the insulating gasket. A port sealing member, in which a filter section and a cap-shaped terminal section are integrated with each other, is connected onto the collector.