HP Deskjet 6540 Color Inkjet Printer - Manual (Page 10)

4.3 Print Cartridge Status lights (HP Deskjet 6540-50
series)
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
The Print Cartridge Status lights are located in the center of the printer control panel.
1. Print Cartridge Status lights
HP Deskjet 6500 series printers User's Guide
10