HP 4550 Service Manual - Page 259

No image available Character voids Use media that meets HP paper specifications. • The surface of the paper is too rough or too smooth for proper toner adhesion. • The wrong side of the paper is being used for printing. • The transparencies are not designed for proper toner adhesion. • The transfer roller is defective. • The laser scanner assembly is defective. Colorless output (black only)
Make sure clutch CL2 is connected (plugged into the paper PCA).
This defect can be caused by improper timing on the ITB clutch gears. Make sure that the cams are in sync. The two white gears on the left side of the printer (see Figure 6-47) should have two timing marks pointing toward each other. • Cams with a single line should be off one tooth clockwise on the right gear. • Cams with a double line should be aligned.
Check for a defective development PCB. If defective, replace the development PCB.
Check for a defective DC controller PCB. If defective, replace the DC controller PCB. Distorted image
The paper does not meet HP paper specifications or is stored improperly.
The printer's operating environment does not meet HP specifications.
The connection of the cables to the laser scanner is poor.
The connection of the cables to the ECU is poor.
The laser scanner is defective.
The DC controller is defective. Dropouts
The paper does not meet HP paper specifications.
The printer's operating environment does not meet specifications.
The print density is set incorrectly. Change to a darker setting and retry printing.
The DC controller PCA is defective.
The high-voltage power supply PCA is defective.
The transfer roller is defective. C7085-90921 Chapter 7 Troubleshooting 257