HP Deskjet 6620 Color Inkjet Printer - Manual (Page 9)

Resume button and light
The Resume light flashes when an action is required, such as loading paper or
clearing a paper jam. When the problem is solved, press the Resume button to
continue printing.
4.3 Print Cartridge Status lights
The Print Cartridge Status lights indicate the status of the print cartridges.
Status of the Print Cartridge Status lights Status of the print cartridges
On and solid
Low on ink
Flashing Service required
1. Print Cartridge Status lights
HP Deskjet 6600 series printer User's Guide
9