On a recent service call, my customer complained to me that their HP LaserJet P4014 was having some print quality issues. When I printed a test page I noticed that there were several areas down the left side of the page that had light print. My first thought was to replace the toner cartridge but the customer informed me that they had already done so but the problem had been on-going.
Since the light print was not consistent down the page, but happened at intervals, I knew right away I could rule out the laser scanner assembly as the problem. After running a half test and confirming that the defect was on the page before the image was fused, I knew it was either the transfer roller or toner cartridge.
Since the toner cartridge had been replaced several times I checked the transfer roller, which showed an area on the roller that was roughed up and that coincided with the area of light print on the page. I ordered and installed a new transfer roller and the image quality was restored.
Note: HP has a repetitive defect ruler in their service manuals. Most people think this is for black marks on the page. This ruler can also be used for light marks. If you think you have the solution but want to verify you are replacing the right part, check the repetitive defect ruler in the service manual. Also, I personally never install third party transfer rollers in machines. I’ve had way too many issues with them. Whenever ordering a maintenance kit or replacing the transfer roller, I recommend getting an OEM transfer roller.
Kevin Gumpp is a certified printer technician and freelance writer for TKO Electronics/Market Point. TKO Electronics/Market Point is a Lexmark Elite Authorized Parts Distributor selling Lexmark printer parts and a HP PartsOne Partner selling HP printer parts. If you have a question regarding this topic or have any other printer repair related questions or topics for which you would like more information, please send an email to email@example.com.