Method of advancing successive sheets of media

Abstract

A method of advancing successive sheets of media by providing a gear and a pick roller configured to rotate independently between a first and a second relative orientation; advancing a first sheet at a first advance speed to an intermediate roller by driving the gear to rotate the pick roller with the gear and the pick roller oriented at the first relative orientation; advancing the first sheet at a greater advance speed by rotating the intermediate roller, thereby orienting the gear and the pick roller in the second relative orientation; advancing the first sheet until the pick roller is in contact with a second sheet; driving the gear while the pick roller remains stationary until the gear and the pick roller are oriented in the first relative orientation; and advancing the second sheet at the first advance speed by driving the gear to rotate the pick roller.

1 . A method of advancing successive sheets of media from a media input holder, the method comprising:
 providing a pick assembly including a gear and a pick roller configured to rotate independently between a first relative orientation and a second relative orientation;   advancing a first sheet of media from the media input holder at a first advance speed to an intermediate roller by driving the gear to rotate the pick roller in a forward direction with the gear and the pick roller oriented at the first relative orientation;   advancing the first sheet at a second advance speed greater than the first advance speed by rotating the intermediate roller;   rotating the pick roller in the forward direction at a first angular velocity while the gear rotates at a second angular velocity that is less than the first angular velocity until the gear and the pick roller are oriented in the second relative orientation;   advancing the first sheet until it is out of contact with the pick roller, so that the pick roller is in contact with a second sheet that was previously underlying the first sheet;   driving the gear in the forward direction while the pick roller remains substantially stationary until the gear and the pick roller are oriented in the first relative orientation; and   advancing the second sheet of media at the first advance speed to the intermediate roller by driving the gear to rotate the pick roller in the forward direction with the gear and the pick roller oriented at the first relative orientation.   
     
     
         2 . The method according to  claim 1 , wherein the step of driving the gear in the forward direction while the pick roller remains substantially stationary further comprises providing a first gap distance between a trail edge of the first sheet of media and a lead edge of a second sheet of media. 
     
     
         3 . The method according to  claim 2 , wherein the step of advancing the second sheet of media at the first advance speed to the intermediate roller while the intermediate roller advances the first sheet at a greater advance speed increases the gap between the trail edge of the first sheet of media and the lead edge of the second sheet of media by a second gap distance. 
     
     
         4 . The method according to  claim 3  further comprising:
 advancing the first sheet of media to a feed roller; and 
 rotating the feed roller in a reverse direction while the intermediate roller rotates in the forward direction in order to align a lead edge of the first sheet of media. 
 
     
     
         5 . The method according to  claim 4  further comprising detecting a lead edge of the first sheet of media before the first sheet of media reaches the feed roller. 
     
     
         6 . The method according to  claim 4  further comprising rotating the feed roller in a forward direction to advance the aligned first sheet of media. 
     
     
         7 . The method according to  claim 4 , the gearing of the feed roller and an output roller being configured such that the output roller and the feed roller rotate in the same direction. 
     
     
         8 . The method according to  claim 7  further comprising:
 advancing the first sheet of media to the output roller; 
 rotating the output roller and the feed roller in the forward direction; 
 advancing the second sheet of media to the feed roller; 
 rotating the output roller and the feed roller in the reverse direction; and 
 again rotating the output roller and the feed roller in the forward direction, wherein the steps of providing the first gap distance and increasing the gap by a second gap distance further comprise providing a sufficiently large gap between the trail edge of the first sheet and the lead edge of the second sheet that the step of rotating the output roller and the feed roller in the reverse direction does not cause the trail edge of the first sheet to reach the reversely rotating feed roller before changing the rotation direction of the output roller and the feed roller to the forward direction. 
 
     
     
         9 . The method according to  claim 2 , the intermediate roller rotating at an angular velocity of ω i ;, the pick roller gear being driven at an angular velocity of ω g , the angle between the first relative orientation and the second relative orientation being θ, and a diameter of the intermediate roller being d i , wherein the first gap distance is substantially equal to (ω i d i πθ/360ω g )−s, where s is a distance that the lead edge of the second sheet extends past a point of contact with the pick roller. 
     
     
         10 . The method according to  claim 9 , a distance between the lead edge of the second sheet to the intermediate roller being S, the diameter of the pick roller being d p  and the diameter of the intermediate roller being d i , wherein the gap between the trail edge of the first sheet of media and the lead edge of a second sheet of media is increased by a second gap distance that is substantially equal to (ω i d i S/ω g d p )−S. 
     
     
         11 . The method according to  claim 10 , wherein a total gap distance provided between the trail edge of the first sheet and the lead edge of the second sheet is substantially equal to (ω i d i πθ/360ω g )−s+(ω i d i S/ω g d p )−S. 
     
     
         12 . A method of advancing, aligning and printing on successive sheets of media, the method comprising:
 providing a pick assembly including a gear and a pick roller configured to rotate independently between a first relative orientation and a second relative orientation;   advancing a first sheet of media from the media input holder at a first advance speed to an intermediate roller by driving the gear to rotate the pick roller in a forward direction with the gear and the pick roller oriented at the first relative orientation;   advancing the first sheet at a second advance speed greater than the first advance speed by rotating the intermediate roller;   rotating the pick roller in the forward direction at a first angular velocity while the gear rotates at a second angular velocity that is less than the first angular velocity until the gear and the pick roller are oriented in the second relative orientation;   driving the gear in the forward direction while the pick roller remains substantially stationary, when the pick roller contacts a second sheet of media previously underlying the first sheet of media, until the gear and the pick roller are oriented in the first relative orientation;   advancing the first sheet of media to a feed roller;   rotating the feed roller in a reverse direction while the intermediate roller rotates in the forward direction in order to align a lead edge of the first sheet of media;   rotating the feed roller in a forward direction to advance the aligned first sheet of media to a print region;   printing on the aligned first sheet of media;   advancing the second sheet of media at the first advance speed to the intermediate roller by driving the gear to rotate the pick roller in a forward direction with the gear and the pick roller oriented at the first relative orientation;   advancing the second sheet of media to the feed roller;   rotating the feed roller in a reverse direction while the intermediate roller rotates in the forward direction in order to align a lead edge of the second sheet of media;   rotating the feed roller in a forward direction to advance the aligned second sheet of media to a print region; and   printing on the aligned second sheet of media.   
     
     
         13 . The method of  claim 12 , wherein the step of driving the gear in the forward direction while the pick roller remains substantially stationary further comprises providing a first gap distance between a trail edge of the first sheet of media and a lead edge of a second sheet of media. 
     
     
         14 . The method according to  claim 13 , wherein the step of advancing the second sheet of media at the first advance speed to the intermediate roller while the intermediate roller advances the first sheet at a greater advance speed increases the gap between the trail edge of the first sheet of media and the lead edge of the second sheet of media by a second gap distance. 
     
     
         15 . The method according to  claim 14 , the gearing of the feed roller and an output roller being configured such that the output roller and the feed roller rotate in the same direction. 
     
     
         16 . The method according to  claim 15  further comprising advancing the first sheet of media to the output roller, wherein the steps of providing the first gap distance and increasing the gap by a second gap distance further comprise providing a sufficiently large gap between the trail edge of the first sheet and the lead edge of the second sheet that the step of rotating the output roller and the feed roller in the reverse direction does not cause the trail edge of the second sheet to reach the reversely rotating feed roller before changing the rotation direction of the output roller and the feed roller to the forward direction. 
     
     
         17 . The method according to  claim 12  further comprising detecting a lead edge of the first sheet of media before the first sheet of media reaches the feed roller.