Detection of Power Frequency for Moving a Document Table
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
The frequency of AC power applied to an AC synchronous motor for moving a document table is detected by counting pel (picture element) lines in a predetermined distance. Fig. 1 shows scanning apparatus 1 in which the document table 2 is reciprocally moved by the AC synchronous motor 3 through rack and pinion mechanism 4. The document table 2 is provided with document glass 5 and control marks 6 and 7. The marks 6 and 7 are printed on the backsurface of the document table 2. The mark and document, face down on the document glass 5, are moved relative to optical slit 8 of an optical scan system including a light source (not shown), mirror 9, lens 10 and CCD (charge-coupled device) sensor array 11. The AC synchronous motor 3 is driven by 50 Hz or 60 Hz. Fig. 2 shows the cycle time or CCD charge integration time period.