Patent ID: 6908164

Claim:
A printer, comprising: a DC power source; an electronic controller for controlling operations of the printer including a printing mechanism of the printer; a power control circuit connected between the DC power source and the electronic controller for controlling delivery of DC power to the electronic controller, the power control circuit comprising: a power control transistor connected between the DC power source and the electronic controller, an ON state of the power control transistor effecting DC power delivery to the electronic controller, an OFF state of the power control transistor preventing DC power delivery to the electronic controller; a user closeable switch connected in line with at least one other circuit component that receives power from the DC power source when the user closeable switch is closed to set up a voltage condition across terminals of the power control transistor that places the power control transistor in its ON state, the user closeable switch biased into an open condition; and latching circuitry connected in the power control circuit, the latching circuitry latching into a conducting state upon closure of the user closeable switch to maintain the voltage condition even after the user closeable switch returns to its open condition; and a switch condition feedback path from the power control circuit to the electronic controller for providing a switch closed signal to the electronic controller when the user closeable switch is closed; a control path connected between the electronic controller and the latching circuitry; when the power control transistor is in its ON state and the electronic controller is receiving DC power, the electronic controller responds to receipt of a switch closed signal by modifying an output on the control path to cause the latching circuitry to unlatch into a non-conducting state thereby eliminating the voltage condition and placing the power control transistor in its OFF state.