HP Color LaserJet 8500 Service Manual - Page 436

Note Sealed envelopes To prevent envelopes from sealing in the printer, set the envelope size in the printer driver as a custom size. However, setting envelopes as a custom size can cause poor fusing. Media jams When troubleshooting media jams, remember that jams are posted as a result of timing errors. That is, media fails to arrive at, or fails to clear, the paper path sensor in the allotted time. The paper path timing is set by the controller board. Stuck or defective sensors cause the paper path timing to post a jam message at power on, as do scraps of paper caught in the paper path. Use figure 222 to locate the paper path sensors. The media jam message code identifies the sensor that failed to change state in the required time. Check that the paper path sensors are free throughout their full range of travel. All interlock switches must be operational in order for the printer to clear media jam messages. 434 Chapter 7 - Troubleshooting EN