Paper feeding apparatus

A paper feeding apparatus comprising:

• a main body configured such that a paper discharge outlet is formed in an upper portion of a front side thereof, a space is formed therein, and a door configured to be selectively opened and closed is formed in the front side thereof;
• a paper support plate formed in a plate shape so that paper is stacked and supported thereon;
• an elevation unit installed inside the main body, and configured to selectively elevate and lower the paper support plate;
• a power unit mounted in a lower part of the main body, and configured to move the paper support plate;
• a sensor configured to measure a weight of the paper stacked on the paper support plate;
• and
• a controller configured to control driving of the power unit in conjunction with the sensor;
• wherein the controller:
• when the sensor detects a change in weight of the stacked paper, elevates the paper support plate in association with a moving distance calculated according to a reduction in weight by driving the motor to extend the multi-stage screw;
• and
• further includes a communication unit configured to transmit a paper replenishment request signal when the paper feeding apparatus senses a paper shortage state and transmit a paper replenishment completion signal when the paper feeding apparatus senses a paper replenishment completion state;
• wherein the controller further includes a height detection unit configured to detect whether the paper support plate reaches a desirably set remaining amount height;
• and the controller generates a paper shortage signal when the height detection unit detects a situation in which the paper support plate reaches the set remaining amount height;
• wherein the elevation unit includes:
• a plurality of guide rails formed inside the main body in a vertical direction;
• a plurality of guide rods formed inside the main body in a vertical direction, and arranged in parallel with the guide rails;
• and a multi-stage screw formed under the paper support plate;
• wherein the paper support plate is configured such that a plurality of bushings to be fitted around the guide rods are formed and insertion grooves into which the guide rails are coupled are formed therein;
• wherein the power unit includes a motor mounted in a lower part of the main body and provided with a driving pulley, a driven pulley formed at a lower end of the multi-stage screw, and a chain configured to connect the driving pulley and the driven pulley;
• and
• wherein the multi-stage screw includes:
• a first-stage screw connected to a driven pulley, and provided with a thread that is formed on an outer circumferential surface thereof;
• a second-stage screw screwed to the first-stage screw, and provided with a thread that is formed on an outer circumferential surface thereof;
• a third-stage screw screwed to the second-stage screw, and provided with a thread that is formed on an outer circumferential surface thereof;
• and a screw housing screwed to an outside of the third-stage screw, and provided with a top end that is fixed to the paper support plate.