Embossing device, embossing method, and embossed can

An embossing device for embossing on a can barrel by an embossing turret, the embossing device comprising:

• a plurality of inner rolls and a plurality of outer rolls each rotating on a corresponding axis of the inner roll and a corresponding axis of the outer roll and revolving around a rotational shaft of the embossing turret in a synchronized way;
• a plurality of holding units revolving around the rotational shaft while conducting a predetermined contact and retract movement wherein at least one of the holding units contacts with and retracts from at least one of the inner rolls and a swing movement wherein at least one of the holding units is adapted to swing and push the can barrel to at least one of the inner rolls to rotatably hold the can barrel;
• a driving unit for rotating the can barrels, held by the plurality of holding units;
• and
• an encoder attached to the rotational shaft;
• wherein each of the plurality of holding units includes a sensor for detecting a match mark on the can barrel, and a rotational positioning controller for receiving signals from the sensor and the encoder and controlling the driving unit based on the signals, and
• the rotational positioning controller comprises a calculation processing part, a machine position detection part, and a control part for the driving unit, and the rotational positioning controller is configured so that
• from a predetermined positioning start position to a position where the sensor detects the match mark, the can barrel is adapted to be rotated at a circumferential speed same as a circumferential speed of at least one of the inner rolls,
• from the position where the sensor detects the match mark to a predetermined positioning position, an amount of positional variations of the can barrel with the corresponding inner roller is adapted to be obtained and a speed of a rotation of the can barrel based on the amount of positional variations is adapted to be controlled to correct a position of the can barrel, and
• from the predetermined positioning position, the inner roll and the outer roll are synchronously operated for embossing the can barrel.