In fact, the faint issue after refilling the HP CE285A cartridge applies to all cartridges of the same type. Namely, these include the following cartridges:
Canon 712, Canon 725, Canon 728, HP CE285A, HP CB436, HP CB435A, HP CE278, HP CF283A, there may be some other similar models.
1. If this is your first fill, then the faint print is most likely caused by poor quality toner. These cartridges are demanding on the toner.
2. Deterioration of the drum (photo drum). this is the second most common defect due to which the cartridge prints faintly with no contrast (requires replacement of the photo roll)
3. Wear of the magnetic shaft. The surface of the roller becomes smooth and the toner adheres less (requires replacement of the magnetic roller). Treatment of the shaft shell with acetone and cloth helps.
4. Wear of the metering blade (metering ruler). Toner adheres and elasticity is lost. Most often this is the appearance of vertical pale narrow stripes.
If this is a new original cartridge and after refueling it began to print faintly, then we specify what toner it was filled with. The toner hopper MUST be cleaned with old genuine toner before refilling. If all this is done correctly, then we look at the surface of the drum.
If you look at the surface of the drum unit at an angle to light, you will notice grooves (scratches) that form from friction with the squeegee (cleaning blade). If the surface is very scratched and the grooves are deep, the faint print of the cartridge is most likely caused by the wear of the drum unit. It needs to be replaced.
This is what the surface of a new drum unit looks like.
And this is the surface of the drum cartridge, which prints faintly due to wear
Next, we change the drum unit and check the print quality. Below are images of test pages before and after replacing the photo roll.
Test sheet before replacing the photo tube (the cartridge was refilled about 5 times)
Test sheet after replacing the photo roll (on the same cartridge)