	US 7,582,849 B2
	Thermal head, driving method and thermal head drive circuit
Sumio Watanabe, Shinagawa (Japan); Fumio Sakurai, Shinagawa (Japan); Yukihiro Mori, Shinagawa (Japan); Norio Endo, Shinagawa (Japan); Shuko Yamaji, Shinagawa (Japan); and Tomoyuki Yokoyama, Shinagawa (Japan)
Assigned to Fujitsu Component Limited, Tokyo (Japan)
Filed on May 24, 2006, as Appl. No. 11/420,112.
Claims priority of application No. 2005-253863 (JP), filed on Sep. 01, 2005.
Prior Publication US 2007/0045280 A1, Mar. 01, 2007
Int. Cl. H05B 1/02 (2006.01)

U.S. Cl. 219—481 [219/497; 219/483; 219/486; 399/67; 307/39]

3 Claims

1. A control circuit that drives a thermal head with a common potential supplied via a power supply terminal, comprising:

first and second current detection circuits that detect respective first and second currents supplied in respective first and second power supply lines to the power supply terminal;

a control unit that detects a failure in the first and second power supply lines by detecting the current to be supplied to the power supply terminal while the thermal head is driven based on evaluation data; and

first and second switching circuits that switch supply and suspension of supply of power to the respective first and second power supply lines, wherein:

when a failure is detected in the first power supply line and not the second power supply line, the control unit controls the first switching circuit to suspend supply of power to the first power supply line and performs printing in a low-speed printing mode using a low-speed printing mode drive current supplied via the second power supply line to the power supply terminal.