| 摘要 |
The object of the present invention is to realize a charging device of a backup power supply for supplying power to perform backup operation to a printer by simplified circuit configuration. The other object of the present invention is to provide a printer which can decrease use of components such as a primary battery undesirable for environment and can realize low cost and low power consumption. The main power supply unit (6B) of the present invention transits to sleep mode from ON state when a panel switch (5) is turned off. A RTC (34) has a timer (34B) and a comparator (34C), checks output voltage of the rechargeable battery (36a) by the comparator (34C). When the comparator (34C) detected that the output voltage became lower than a reference voltage RefV, the RTC (34) outputs a power ON signal (34d) until the timer (34B) counts up 3 minutes. A second switch (38) is turned on by the power ON signal (34d), and the main power supply unit (6B) returns to ON state only for 3 minutes in order to charge the rechargeable battery (30a) by using power supplied from the main power supply unit (6B). <IMAGE> |
