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C73x & X73x — Charge Roll White Gapping

Document ID:SO6621

Usergroup :External


C73x; X73x; Charge roll white gapping; X734de; X736de; X738de; C734dn; C736n; Light patches repeating down page; White patches;


Defect Symptom

Charge Roll White Gapping consists of light or white patches repeating down the page. See sample below.

Click Image to Enlarge




  1. Repeating defects involving a single color (Cyan, Magenta, Yellow, or Black) are usually due to defective photoconductor units or toner cartridges, and not the Transfer Belt Module (TBM), fusers, or other printer hardware.
  2. Toner cartridges or photoconductor units being improperly installed can also cause defects similar to the one pictured above. Remove and reinstall the toner cartridges and photoconductor units, making sure that they are fully seated. (NOTE: When removing and reinstalling the photoconductor units, do not touch the shiny blue drums.)
  3. Perform the "Color Adjust" procedure in the "Quality" menu.
  4. Print the "Print Defects Guide" in the "Help" menu and review the print samples.
  5. If the defect repeats down the page, use the defect ruler to determine which component is defective.
  6. The example shown is at PC Drum frequency, and is caused by a defective photoconductor unit.
  7. A swap test of the photoconductor can be performed to confirm a suspect PC unit.
  8. For optimum print quality and reliability, Lexmark recommends always replacing photoconductor units in complete sets.
  9. When replacing photoconductor units, be sure to reset the photoconductor life counter for each photoconductor unit replaced.



Contacting Lexmark

Please contact Lexmark Technical Support if you need additional assistance. NOTE: When calling for support, you will be asked for your machine/model type and serial number (SN). If you need help locating your printer's model type and serial number (SN), click here.

Please call from near the printer in case the technician on the phone asks you to perform a troubleshooting task on the printer.  




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