HP 2500 L Service Manual
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Page 81
EN 4 Theory of operation79 Step 9: roller charging (transfer belt cleaning roller) The transfer belt cleaning roller, to which a dc positive bias is applied, imparts a positive charge to the residual toner on the transfer belt. This positive charge is stronger than the positive charge applied in step 8, so the earlier charge now behaves like a negative charge. Figure 34. Step 9: roller charging (transfer belt cleaning roller)
Page 82
80Theory of operation C9706-90926 Step 10: transfer belt cleaning A dc positive bias is applied to the transfer belt to produce a difference in potential between the belt and the photosensitive drum. This causes the transfer of the residual toner to the drum. Figure 35. Step 10: transfer belt cleaning
Page 83
EN 4 Theory of operation81 Step 11: drum cleaning The cleaning blade scrapes the residual toner off of the photosensitive drum, where the waste toner screws collect and deposit the toner into the waste toner case. Figure 36. Step 11: drum cleaning
Page 84
82Theory of operation C9706-90926 Print cartridge The printer has four print cartridges: yellow, magenta, cyan, and black. Each print cartridge contains a developing cylinder, toner-feed roller, and stirrer. The developer motor rotates these parts, so that each print cartridge can use toner to form a visible image on the drum. The carousel motor rotates the E-label reader, which communicates E-label information to the dc controller. The developing rotary/toner level detection PCB uses an LED (light...
Page 85
EN 4 Theory of operation83 Imaging-drum E-label The E-label is nonvolatile memory, which is built into the imaging drum and stores usage information. When the imaging drum is installed in the printer, the E-label makes constant contact with the E-label reader. The E-label reader sends memory information to the dc controller, which updates the information and sends it back to the E-label. The dc controller instructs the E-label to read information when: the printer is turned on the top cover is...
Page 86
84Theory of operation C9706-90926
Page 87
EN 5 Removal and replacement85 5Removal and replacement Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Removal and replacement strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Electrostatic discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 User-replaceable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Required tools. . . . . . ....
Page 88
86Removal and replacement C9706-90926 Toner-catch tray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Transfer-roller plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 Transfer roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Feed-drive shaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 ECU pan . . . . . . . . . . . . ....
Page 89
EN 5 Removal and replacement87 Introduction Removal and replacement strategy This chapter documents removal and replacement of field replaceable units (FRUs) only. Replace parts in the reverse order of their removal. Directions for difficult or critical replacement procedures are included. WARNING!The sheet-metal edges of the product can be sharp. Use caution when working on the product. NoteNote the length, diameter, color, type, and location of each screw. Be sure to return each screw to its...
Page 90
88Removal and replacement C9706-90926 Before performing service Pre-service procedures 1 Remove all media from the product. 2 Place the product on an ESD mat. If an ESD mat or an ESD-protected workstation is not available, discharge body static and ground the product chassis before servicing the product. 3 Remove the imaging drum (see page 90). 4 Remove the print cartridges (see page 91). 5 Unplug the power cord and the interface cable. 6 Lift the printer off of optional tray 3 (if installed).