HP 2500 L Service Manual
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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)
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
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
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 emitter) and a photodiode (light receiver) to determine the toner level in each print cartridge. Figure 37. Print cartridge
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 closed a command is sent from the video controller The dc controller instructs the E-label to write information when: a specified period occurs during printing a command is sent from the video controller If the E-label reader fails to read or write information four times in a row, the dc controller notifies the video controller that an abnormality exists in the imaging drum. Figure 38. Print-cartridge E-label
EN 5 Removal and replacement85 5Removal and replacement Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Removal and replacement strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Electrostatic discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 User-replaceable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Required tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Before performing service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Pre-service procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Parts removal order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Removal and replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Imaging drum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Print cartridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Jetdirect card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Fuser cover (and fuser) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Right- and left-side covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Control panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 On-off switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Interface cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Formatter cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Formatter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Fuser motor (J702) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Dc controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Optional tray 2 (250-sheet tray) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Carousel motor (J704) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 Front lower cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Back cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Top cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Top door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Air duct and fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Laser/scanner assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 Front cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Density sensor and top-of-page sensor . . . . . . . . . . . . . . . . . . . . . . . . . 119 E-label reader (for imaging-drum E-labels). . . . . . . . . . . . . . . . . . . . . . . 120 Tray 1 (multipurpose tray). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 Tray 1 separation pad assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 Gear assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Waste-toner sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 Rotary-drive assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 Top plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 Print-cartridge carousel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 Registration-roller assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
86Removal and replacement C9706-90926 Toner-catch tray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 Transfer-roller plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 Transfer roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Feed-drive shaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 ECU pan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 Sub-high-voltage transformer PCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 High-voltage transformer PCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 Low-voltage PCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Paper-top sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Fuser-wrap sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 250-sheet feeder pickup roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 250-sheet feeder cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 250-sheet feeder PCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 500-sheet feeder pickup roller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 500-sheet feeder cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 500-sheet feeder motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
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 original location during reassembly. Incorrectly routed or loose wire harnesses can interfere with other internal components and can become damaged or broken. Frayed or pinched harness wires can be difficult to locate. When replacing wire harnesses, always use the provided wire loops, lance points, or wire-harness guides. Electrostatic discharge CAUTIONThe product contains parts that are sensitive to electrostatic discharge (ESD). Always service the product at an ESD-protected workstation, or use an ESD mat. Watch for the ESD symbol (shown at left) to identify the parts that are sensitive to ESD. Protect these parts by using an ESD wrist strap and protective ESD pouches. User-replaceable parts This chapter contains removal and replacement procedures for the imaging drum (see page 90) and the print cartridge (see page 91). To remove and replace the pickup roller or separation pad, see “User-replaceable parts ” on page 47. Required tools The following tools are needed to service this product: #2 Phillips screwdriver with magnetic tip Small flatblade screwdriver Small needle-nose pliers ESD mat Penlight CAUTION A PoziDriv screwdriver will damage screw heads on the product. Use a #2 Phillips screwdriver. If you use a multispeed screwdriver, use a torque limiter.
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).