HP 45 (51645A) Cartridge Prints One Page After Cleaning, Then Stops: Root Causes and Fixes

Question

After cleaning a very old HP 45 (51645A) ink cartridge-especially using an ultrasonic cleaner-it prints perfectly at first, but then after one page (or after letting it sit for a few minutes) it stops working again. Why does this happen, and what can I do to fix it?

Answer

What you're describing is extremely common with older HP 45 (51645A) cartridges: they can look "fully revived" right after cleaning, then fail again shortly after. In most cases, the printhead itself isn't the only issue-the ink supply path inside the cartridge is the real bottleneck.

1) The key design detail: HP 45 ink bag + internal ink chamber

Your proposed answer is on-point: the HP 45 stores ink in an internal ink bag (reservoir). Below/around that, the cartridge also has an internal ink chamber/ink box and pathways that feed ink down to the printhead.

Here's why that matters:

• Cleaning (including ultrasonic cleaning) can temporarily clear ink crust at the nozzles/faceplate.

• But if there's a restriction deeper inside-especially in the ink chamber/ink feed path-the cartridge can only print what ink is already close to the nozzles.

• After one page, the printhead needs replenishment. If the feed path can't supply ink fast enough, the cartridge "dies" again.

So the "one page then stops" pattern often means: ink delivery can't keep up, not that the head can't fire.

2) Most common causes of "prints once, then quits"

A) A clog in the internal ink feed path ("ink box" restriction)

This is the most likely cause, especially with a very old cartridge:

• Dried ink can form a partial plug in the internal chamber.

• Cleaning loosens some material, and it may re-settle or migrate and block flow again.

• The cartridge prints initially because ink is already in the printhead area, then starves.

B) Air ingestion / poor priming after cleaning

Ultrasonic cleaning and flushing can introduce air bubbles:

• Air breaks the continuous ink column.

• You get a short burst of perfect printing, then sudden dropout after a pause.

• Waiting a few minutes makes it worse because air can move into the feed path and expand/redistribute.

C) Weak backpressure control (bag deterioration)

With age, the bag/reservoir system can degrade:

• The bag may not regulate flow correctly.

• Ink delivery becomes inconsistent-fine for a moment, then unstable.

• This shows up as "works fresh, fails after sitting."

D) Ultrasonic side effects: loosening debris that re-clogs

Ultrasonic cleaning can be helpful, but it can also:

• Break loose chunks of dried ink from inside passages,

• which then travel and re-block narrow channels.

E) Electrical aging (less common than flow issues, but real)

Very old cartridges can suffer from:

• Failing internal resistors/heaters,

• delaminated flex contacts,

• intermittent electrical connection at the printer's carriage contacts.

This usually looks like inconsistent firing or missing sections that don't respond even when ink flow is good-but it can overlap with starvation symptoms.

3) Practical fixes and tests (to confirm ink starvation vs. electrical failure)

Step 1: Do an ink starvation check

• Print a high-coverage test pattern (thick blocks of black).

• If it starts strong and fades quickly, that's classic starvation.

• If specific nozzles are permanently dead regardless of priming/flow, suspect electrical damage.

Step 2: Re-prime to remove air

After cleaning, the cartridge often needs proper priming:

• Use a cartridge priming tool or controlled suction at the nozzle plate (carefully).

• Goal: pull ink through until flow is continuous and bubble-free.

• Blot test: you should see a solid, even ink patch, not a spotty/foamy one.

Step 3: Address the internal chamber restriction

Because the HP 45 has that internal chamber/ink box, a nozzle-only clean may not be enough:

• A deeper flush (not just soaking the nozzle plate) is needed to clear the internal path.

• Be cautious with aggressive suction: too much can damage internal regulation or pull more debris into a choke point.

Step 4: Let it rest correctly

If air is involved:

• Let the cartridge sit nozzle-down on a damp lint-free pad briefly (not dripping wet-just slightly damp) to stabilize ink at the faceplate.

• Avoid leaving it exposed to dry air, which promotes re-drying at the nozzles.

Step 5: Verify contacts

• Clean printer carriage contacts and cartridge contacts with appropriate cleaner (and ensure they're fully dry).

• A poor contact can mimic "sudden failure," especially after the carriage has moved and warmed slightly.

4) Why it works after cleaning-then fails after a short wait

That "prints perfectly, then after a few minutes it stops" timing is a big clue:

• After cleaning, the nozzle plate is wet and ink is present at the head → prints great.

• During a short pause, air or partial vacuum can form in the feed path, or loosened debris can shift.

• When you print again, the printhead tries to draw ink, but the internal path can't supply it → sudden dropout.

This is exactly why your note is important: with HP 45, the clog can be in the internal ink chamber/ink box, not just at the printhead surface.

5) If the cartridge is extremely old: know when "revival" hits a limit

HP 45 cartridges are durable, but age eventually wins:

• internal materials fatigue,

• ink pathways become permanently restricted,

• electrical elements can degrade.

Sometimes you can improve it, but you may not restore long-term reliability-especially if it repeatedly returns to the same failure pattern.

Addressing printer ink and cartridge issues can be complicated because the problems are hands-on and depend heavily on internal flow behavior that's hard to verify remotely. So, we're not able to provide remote troubleshooting, suggestions, or support for printer repairs. We do offer an in-person evaluation and repair service through our local diagnostic facility: printer repair service (https://bchtechnologies.com/printer-repair-service). Due to high demand, we operate on a first-come, first-served basis, and it may take a few weeks before we can accept your printer for drop-off. Our services are structured to repair either a whole printer or specific parts, with clear instructions on how to proceed. That said, we understand our rates aren't the most economical, so we strongly recommend self-help through online research. You can start by checking YouTube or visiting our channel homepage: BCH Technologies on YouTube (https://youtube.com/@bchtechnologies). Use the search icon next to "About" on the right-hand side of the menu bar to find the most relevant videos. I receive dozens of requests every day asking about videos for specific topics, and after creating videos over the past nine years, it's difficult to remember every single one-so YouTube's search function is the fastest approach. Plus, YouTube may suggest helpful videos from other channels that can assist you as well.

Thanks again for reaching out and for supporting our work. I hope this explanation helps you pinpoint whether your HP 45 is suffering from an internal ink-path restriction, air/priming issues, or age-related failure, and helps you get more consistent printing.