If replacing the toner cartridge doesn’t resolve light print problems, check the rollers.


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. Continue reading

Toner Specks Running Down the Page Vertically


Toner-Speck-on-paperA common problem that I run into with HP Color LaserJet 3500, 3550, 3700 printers is toner specks running down the paper vertically. This problem is different than periodic dots that show up on the page at defined intervals, otherwise known as repetitive defects. With a repetitive defect, note the color of the dot and measure the distance between the dots. The service manual describes what internal roller is causing the problem and you can simply replace the appropriate part.

Random toner specks can be a little more difficult to diagnose. Continue reading