HP M5025 Service Manual - Page 167

Duplexing unit jam detection The duplexing unit provides the following paper-detection sensors to detect paper presence and normal paper-feed operation. ● Duplexing feed sensor (SR2) ● Duplexing jam sensor (SR1) ● Top-of-page sensor (SR5 in the device) The duplexing driver CPU determines whether or not a paper jam exists by checking if paper is present at the sensor at the specified timing. The specified timing is stored in the CPU memory. If the CPU determines that a jam has occurred, it stops the duplexing feed operation and notifies the formatter. Table 4-4 Duplexing unit jam detection Jam type Reversing delay Duplexing delay Duplexing pickup delay Description Specified timing (approximate) When SR2 does not detect paper within the specified timing after SR6 detects the media trailing edge, the CPU notifies the formatter of a reversing delay jam. T = 1.1 s When SR1 does not detect paper within the specified timing after SR2 detects the media leading edge, the CPU notifies the formatter of a duplexing delay jam. T = 1.5 s When SR5 does not detect paper within the specified timing after the duplexing pickup operation begins, the CPU notifies the formatter of a duplexing pickup delay jam. T = 3.3 s Automatic delivery is available if either SR1 or SR2 detects paper before beginning the print operation. ENWW Duplexing unit 137