Put the ink cartridge of HP printer back into the slot, press and fix it. Other faults of HP printer and their solutions;
When printing, the ink is insufficient and the handwriting is illegible: if the nozzle blockage is not serious, then clean it directly on the printer. If repeated cleaning still doesn't work, you can take down the ink cartridge and soak the nozzle in warm water for a while.
Treatment of nozzle soft plug: Soft plug refers to the disconnection failure caused by the increase of ink viscosity on the nozzle for various reasons. Generally, the original ink cartridge can be restored after repeated cleaning.
Handling of dislocation of walking trolley: Once this fault occurs, immediately turn off the power supply of the printer and push the trolley back to the parking space by hand. Find a small sponge or felt, soak it in sewing machine oil and wipe it back and forth with tweezers on the spindle.