HP Color LaserJet Enterprise CP4020 Service Manual - Page 445

Problem Sample Image in a particular color does not print in the correct color. Dropouts appear. The toner is not fully fused to the paper. Cause Solution Poor contact exists in the primary charging bias or developing bias contacts between the print cartridge and the product. Clean each contact of the color that produces the missing color. If the problem remains after cleaning, check the contacts for damage. Replace any deformed or damaged parts. The print cartridge (primary charging roller, developing roller, or photosensitive drum) is defective. Replace the print cartridge of the color that matches the defect. The high-voltage powersupply lower is defective (no primary charging bias or developing bias output). Replace the high-voltage powersupply lower. See High-voltage power supply lower (HVPS-D) on page 163. The laser/scanner unit is defective. Replace the laser/scanner assembly. See Laser/scanner assembly (Y/M) on page 186 or Laser/scanner assembly (C/Bk) on page 190. The secondary transfer roller is deformed or has deteriorated. Replace the secondary-transferroller. See Secondary transfer roller on page 90. The primary charging roller, developing roller, or photosensitive drum is deformed or has deteriorated. Replace the print cartridge of the color that matches the defect. The fuser roller is deformed or Replace the fuser. has deteriorated. The high-voltage powersupply T PCA is defective (no transfer bias output). Replace the high-voltage powersupply upper. See High-voltage power supply upper (HVPS-T) on page 196. The fuser roller or pressure Replace the fuser. See Fuser roller is scarred or deformed. on page 85. The thermistor is defective. Replace the fuser. See Fuser on page 85. The fuser heater is defective. ENWW Solve image-quality problems 413