Improved Bidirectional Document Aligner
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Fig. 1 shows the pivoting idler wheel 11 mounted on shaft 13 which is free to pivot on pin 15 in a plane which is parallel to the plane of the document 17. Document motion is provided by drive wheel 21 which rotates under motor control. Idler wheel 11 is pushed down against document 17 by idler wheel 31 under the tension of spring 35 acting on shaft 33. As shown in Fig 2, drive wheel 21 provides drive force FD on document 17 in combination with wheel 11. Idler wheel 11 has a bearing where it is mounted to shaft 13, and likewise idler wheel 31 has a similar bearing. The friction of these bearings and rolling surface friction provide a drag force FR 11 and FR 31, respectively. These drag forces in combination with the driving force FD tend to move idler wheel 11 to the position 41 shown in dotted lines in Fig. 3.