What Is a Printhead Rank (Head ID) and Why It Matters

Open the box of a new printhead and you will find a small label carrying a short alphanumeric value. That value is the head rank, sometimes called the head ID. It is not a serial number and it is not decoration – it is calibration data for that individual head, and the printer will not print correctly without it.

Why Two Identical Heads Still Need Different Settings

Piezo printheads are manufactured to very tight tolerances, but they are still manufactured. The size of the piezo chamber, the response of the actuator and the flow characteristics of the nozzle channel vary slightly from head to head.

To fire a droplet of a predictable size and speed, the printer has to drive each head with the right voltage and waveform. The rank value is how the factory tells the printer what that head needs. Two heads with the same part number, sitting side by side in the same machine, will carry different rank values.

What Happens If You Ignore It

• Banding and density steps. Slight differences in dot size between channels show up as visible banding in solid fills.
• Colour shift. One channel firing slightly differently is enough to shift a mixed colour.
• Poor dot placement. Mist, satellite droplets and soft edges.
• Shortened head life. Driving a head outside its specified voltage range is the fastest way to retire it early – and it is not covered by any warranty.

Where the Rank Lives

Depending on the head generation, the rank is usually found in one or both of these places:

• On a label attached to the head – a short letter and digit combination, sometimes alongside the part number.
• Stored in the head’s own memory. Many heads used in wide format machines carry a small chip holding the rank and other calibration data, so the printer can read it automatically.

Before you install a head, photograph the label and write the value down. It is very easy to lose the sticker during installation, and re-reading a rank from an installed head is far harder than reading it from the box.

What To Do When Fitting a Head

1. Record the rank from the label, and note the head part number and the machine’s serial number in your maintenance log.
2. Enter the rank in the service menu after fitting, following the procedure in your model’s service manual. Menu names differ between brands, so use the manual rather than a general guide – including this one.
3. Run the head alignment and adjustment routines the service manual specifies. These set dot placement and, on some machines, the voltage bias for the new head.
4. Print a nozzle check and a test pattern before running production work, and compare density across channels.
5. Replace the head data cables at the same time on machines where this is recommended. New head plus worn cables is a classic early failure.

Common Mistakes

• Entering the rank from the old head, or copying a value from a forum post for the same model.
• Losing the sticker, then guessing.
• Fitting the head and leaving the calibration for later – “later” usually means a day of banded production.
• Reusing dampers and cables that were contaminated by the failed head.

FAQ

Is the head rank the same as the head ID?

In practice the two terms are used interchangeably. Some manufacturers distinguish between a rank value you enter manually and an ID stored in the head’s chip, but both serve the same purpose: telling the printer how this specific head behaves.

Can I change the rank later?

You can re-enter it, but you should not change it to a value that was not supplied with the head. If the printed result suggests the rank is wrong, re-check what you entered rather than experimenting.

Do I need the rank if the printer reads the chip automatically?

Record it anyway. If the chip fails or the board is replaced, the label is your only record.

Does an incorrect rank damage the head?

It can. Sustained over-voltage is one of the recognised causes of early head failure, and it is not a manufacturing defect.

Replacing a Head

We supply printheads for Epson DX-series, i3200, Ricoh, Konica and Kyocera platforms, along with the dampers and related parts that should be replaced at the same time. Our step-by-step printhead replacement guide covers the mechanical side; for your specific machine, tell us the model through the contact form and we will confirm the correct head before you order.