Time recorder with automatic correction for momentary discontinuation of power supply

摘要

A time recorder is normally powered by a main power source for supplying a commercial power and occasionally powered by a back-up power source during interruption of the commercial power supply. A clock means counts time to constantly produce a clock pulse, and a digital display constantly digitally indicates updated time data in response to the clock pulse. An analogue display is driven for analogically indicating time information and a recording mechanism is driven for recording time information on a recording medium. A driving device drives the analog display and recording mechanism in response to the clock pulse to update the time information indicated in the analog display and recorded by the recording mechanism. A detecting device is connected to the main power source for detecting the interruption of the commercial power supply. A controlling device responsive to the detection of the commercial power supply interruption inhibits the operation of the driving device during the commercial power supply interruption so that the driving device suspends the driving of the analog display and recording mechanism to thereby cause a delay of the time information from the updated time data, and operates after recovery of the commercial power supply for controlling the driving device to quickly drive the analog display and recording mechanism to correct for the delay to thereby update the time information.