i replaced the ink in my deskjet 4155 but the app still says the cartridges are empty or not recognized.

Diagnosis

The HP DeskJet 4155e utilizes an electronic handshake system where the printer's carriage pins must establish a perfect electrical circuit with the copper contact pads on the HP 67 ink cartridges. When the HP Smart app reports "Empty" or "Not Recognized" despite a physical replacement, it is usually due to a communication failure. This is often caused by microscopic debris, ink smears, or a thin layer of oxidation on the gold-plated contacts, which prevents the printer from reading the cartridge's unique identification chip. Another common cause is the "HP+ (e-series)" firmware restriction. Because the 4155e is an 'e' series printer, it is designed to strictly enforce the use of original HP cartridges. If you have installed remanufactured or third-party cartridges, the printer may trigger a "Cartridge Problem" or "Non-HP Chip Detected" error. This happens because the printer's firmware checks the digital signature of the chip; if the signature is missing or incorrect, the printer ignores the ink levels entirely and reports them as empty or missing to prevent the use of unauthorized supplies.

How to Fix It

To resolve the recognition error and sync the ink levels with the HP Smart app, follow these precise steps:

1. Power on the printer and open the front ink access door. Wait for the ink carriage to slide to the center of the machine.
2. Press down firmly on the top of the cartridge (either the black or tri-color) to release the latch, then pull the cartridge straight out of the slot.
3. Locate the copper-colored contact pads on the back of the cartridge. Use a lint-free cloth or a coffee filter dampened with a small amount of 90% isopropyl alcohol. Gently wipe the copper pads in a circular motion to remove any oils or ink residue.
4. Look inside the printer carriage at the gold-plated pins that meet the cartridge. Using a dry cotton swab, gently clean these pins to ensure no ink buildup is blocking the connection.
5. Ensure the orange plastic protective tape has been completely removed from the cartridge contacts. Even a tiny sliver of adhesive remaining can cause a "Not Recognized" error.
6. Re-insert the cartridges, pressing down firmly until you hear a distinct "click" that locks them into place.
7. Close the access door and perform a "Hard Reset": While the printer is on, unplug the power cord from the back of the machine and the wall outlet. Wait 60 seconds. Plug it back in and allow the printer to reboot.
8. Open the HP Smart app on your device and refresh the printer status page to confirm the ink levels have updated.

If That Didn't Work

• Disable HP Cartridge Protection: If you are using non-HP ink, the printer may be blocking them via a security setting. Access your printer's Embedded Web Server (EWS) by typing the printer's IP address into a web browser. Navigate to Settings > Preferences > Cartridge Protection and select "Disable HP Cartridge Protection," then click Apply.
• Perform a Carriage Reset: Sometimes the carriage sensor hangs. With the printer on, open the ink door, remove both cartridges, and close the door. The printer will flash an "Ink Missing" error. Now, reopen the door and re-insert the cartridges one by one, waiting for the printer to acknowledge each one before inserting the second.
• Update Printer Firmware: An outdated firmware version can cause communication glitches with newer cartridge batches. In the HP Smart app, go to Printer Settings > Advanced Settings > Tools > Printer Updates and check for any available firmware patches.
• Test with a Known-Good Cartridge: If the error persists for only one specific color, the chip on that individual cartridge is likely defective. Try swapping it with a different genuine HP 67 cartridge to determine if the fault lies with the cartridge chip or the printer's internal carriage pins.

Heads Up

• Avoid touching the copper contacts with your bare fingers; skin oils can create an insulating layer that leads to "Cartridge Not Recognized" errors.
• Always use a lint-free cloth for cleaning; standard paper towels can leave behind micro-fibers that interfere with the electrical connection.
• If you are using the HP Instant Ink subscription, ensure your account is active and the printer is connected to Wi-Fi; otherwise, the printer may electronically disable the cartridges.
• Never force a cartridge into the slot; if it doesn't click in easily, check for any remaining plastic packaging or shipping materials inside the carriage.