DOCUMENT DESKEWING SYSTEM

摘要

In a document sheet feeding and registration apparatus for deskewing a document sheet relative to a desired copying position on a copier platen while feeding the document sheet onto the platen into said copying position, there is disclosed a method and apparatus including obtaining an electrical signal corresponding to the actual velocity of the document sheet being fed onto the platen, and actuating an automatic document sheet deskewing device at a precise actuating time occurring slightly before the document sheet reaches the copying position, so that the actuating time of said document sheet deskewing corresponds to the actual velocity of the document sheet. The electrical signal corresponding to the actual document sheet velocity may be obtained by counting the elapsed time between the actuation of first and second switches substantially spaced from one another along the document sheet path upstream of the copier platen. The actuating time of the document sheet deskewing device may be a resettable time delay count after the actuation of said second switch, which time delay count is resettable by a change in the counted time period between the actuation of said first and second switches. The automatic document sheet deskewing device may comprise a releasable skew preventing document feeder releasing the document sheet at said actuating time to another feeder for briefly driving the document sheet into a registration aligning edge while freely allowing deskewing movement of the document sheet thereagainst after said actuating time.