HP Deskjet 3820 Color Inkjet Printer - Manual (Page 68)

checking the print cartridge status
understanding the print cartridge status light
The Print Cartridge Status light flashes when one or both of the print cartridges are
low on ink, improperly installed, or malfunctioning. This light also flashes if the wrong
print cartridge type is used.
1. Print Cartridge Status light
If the ink level is low in a print cartridge, the Print Cartridge Status light stops flashing
when the printer's top cover is opened. If the problem is not related to low ink, the
light continues to flash after the cover is opened.
checking the print cartridge status
Open the printer's top cover when the Print Cartridge Status light flashes. The black
arrow on the top of the print cartridge cradle points to one of five Print Cartridge
Status icons revealing the exact nature of the problem.