HP OfficeJet Pro 7720 Cartridge Problem Repair in Jeongwang-dong, Siheung

Hello, this is Mini PC Lab. Today, a customer from Jeongwang-dong, Siheung-si contacted us regarding a "Cartridge Problem" on an HP OfficeJet Pro 7720 printer. The cartridge problem is a representative error message that occurs when the printer fails to normally recognize the continuous ink cartridges or modified chipless systems installed in the printer.

The HP OfficeJet Pro 7720 is a high-performance A3 multifunction printer supporting printing, copying, scanning, faxing, wired/wireless networking, and automatic duplex printing. It natively supports both A4 and A3 printing, while automatic duplexing is available only for A4 paper. Additionally, for copying and scanning, both the ADF (Automatic Document Feeder) and the flatbed glass support up to A4 size only—A3 copying is not supported on this model, which is helpful to keep in mind when purchasing and using it.

The customer was using a constant-pressure supply system equipped with dampers. A damper serves to prevent ink backflow and offers some protection against ink spilling into the printhead if the external ink tank is accidentally raised higher than the printer. However, during long-term use, the internal piston or rubber valves inside the damper can harden, which actually obstructs the ink flow and ultimately causes smooth ink delivery to the printhead and cartridges to fail.

hp officejet pro 7720

In this repair case, an ink supply failure and a cartridge recognition error occurred simultaneously. Continuous ink printers use aftermarket external chips attached to the cartridges, and static electricity, ink contamination, or system errors caused the chip to become damaged and unusable.

Here is a step-by-step repair guide and maintenance strategy to cleanly resolve this issue.

Step-by-Step Guide to Resolving the HP 7720 Cartridge Problem

Step 1: Inspect the Cartridge and Chip Condition

• Remove Cartridge and Visual Check: Open the printer cover and carefully remove the unrecognized cartridge.
• Check Contact Area Contamination: Inspect the surface of the chip on the bottom and back of the cartridge for ink or dust. If ink is present, wipe it clean with cleaning solution or an alcohol swab, let it dry completely, and reinstall it.
• Identify Damage: If the same error persists after cleaning, the internal circuitry of the chip is damaged and must be replaced with a new chip.

Step 2: Replace the Damaged Cartridge Chip and Inspect Damper

• Replace Aftermarket Chip: Remove the faulty chip attached to the existing cartridge and firmly attach an HP 7720-dedicated CISS chip (or compatible chip) in its proper position.
• Inspect Damper and Ink Flow: Check the pressure using a syringe to see if the damper is blocking the ink flow. If the damper area is clogged and ink does not pass through, replace the damper with a new component or bypass/remove the damper to connect the tube directly using pure constant pressure.
• Prime Cartridge: After replacing the chip, purge the air inside the cartridge and fill it completely with ink so that ink can be supplied to the printhead nozzles immediately.

cartridge chip

Step 3: Install Printhead and Reset System

• Reinstall Cartridge: Firmly insert the cartridge with the replaced chip back into the printhead assembly until it clicks into place.
• Perform System Reset: Turn off the printer power and turn it back on after 10 seconds, or enter the service menu (Engineering Menu) to run an OOBE Reset or Semi-Full Reset to clear the cartridge recognition data.
• Verify Normal Operation: After going through the initialization and printhead alignment process, test whether the error message disappears and head cleaning and printing proceed normally.

Practical Maintenance Tips for Long-Lasting A3 CISS Printers

Maintain External Ink Tank Height (Same Level Surface)

Even if a damper is installed, the external ink tank must always be placed on the exact same level surface as the printer. Pressure imbalances caused by height differences are a major cause of chip recognition errors and printhead flooding.

print test

Check Air Vent Plug Status

The small air plug on the constant-pressure supply unit must remain open at all times during printing. If the air hole is blocked, internal negative pressure develops, stopping ink supply and operating the cartridges empty, which overloads the chip and printhead.

Prevent Cartridge Chip Contamination

When replacing cartridges or refilling ink, be careful not to let ink touch the chip area. If liquid enters the chip circuitry, a short circuit occurs, causing immediate chip failure.

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This has been Mini PC Lab. If you have any inquiries regarding A3 CISS multifunction printer repairs, such as the HP 7720, or cartridge chip replacement, please feel free to contact us anytime. Thank you!