| 摘要 |
<p>DOCUMENT CONVEYING METHOD AND APPARATUS An apparatus and method are provided whereby two superposed strips (26, 28) of documents are conveyed in a direction of conveyance (30) toward a downstream workstation. The strips (26, 28) are conveyed over one another in a direction of superposition whereby the leading edges of documents of one strip alternate in sequence in the direction of conveyance with the leading edges of documents in the other strip. A determination and control (190) circuit is provided to determine whether the leading edges of documents in one strip are tending to creep up on the leading edges of documents in the other strip due to differing speeds of motion of the two superposed strips. If a creeping condition is determined by the circuit (190), the circuit (190) energizes braking means (400) whereby the motion of at least one of the strips is at least temporarily retarded for rectifying the creeping condition. The determination and control circuit (190) comprises a detector (188) for determining when leading ones of documents have been separated from their respective strips; timing pulse generation means (200); counter select means (206) for selectively enabling a first counter (202) and a second counter (204) to count timing pulses (the counters (202, 204) being enabled in alternating fashion after documents are separated in alternating strip fashion from their strips); and, comparison means (207) for comparing the counts in the two counters (202, 204). The detector (188) detects when leading edges and trailing edges of separated documents are conveyed past the detector (188). The counters (202, 204) are enabled to count when the trailing edge of a preceding separated document is detected and are disabled when the leading edge of a just-separated document is detected. The control circuit (190) periodically deenergizes the braking means for a time period extending from the time at which the leading edge of a just-separated document is detected until the time at which the trailing edge of the just-separated document is detected, thereby precluding uneven wear of the braking means.</p> |
