Lines on Print with HP M551

[user544]

Hello-

I've been having trouble with lines going up and down the left side of the page when printing to an HP M551 printer.  I have replaced the ITB and all of the toner cartridges and inspected the fuser and rollers.  I put the printer into cartridge bypass (can't recall the proper name for it) and took out each cartridge one-by-one but with no success.

What seems interesting is that the line appears the worst on the first page of a multi-page printout.  I'm attaching some photos.  I ran a "test page" with three copies.  The first of the three has the line, but even by the second page the line is barely visible and is entirely gone by the third copy.

It seems like something is not getting cleaned up properly after a print but once cleaned up, then the rest of the pages are fine.  Any ideas as to what to troubleshoot next?

[PSSG]

You have performed the required troubleshooting steps.  Looks like an ITB caused line.  Was the replacement ITB a HP OEM or third party part?  Print the Print Quality Troubleshooting pages.  The line is usually more pronounced on color documents.  Review those pages  Then print the color demo page, open the right side door,  and stop the page halfway past the transfer roller.  Inspect the page and new belt.

[Repairatrooper]

If you have the same issue with 2 ITB units, it might be an issue with the secondary transfer roller that is mounted in the right door. Toner can build up behind it.

[user544]

Hello,

The ITB is HP genuine.  I see leftover toner on the transfer belt.  I have a replacement blade/end for the ITB that I can put on the belt as a test.  It seems like toner is not getting scraped/cleaned off of the belt.  Can't figure out why the printer deposits this much toner in the first place.

Steve

[user544]

Hello,

Thank you for the response.  The secondary roller was replaced at the time of the ITB replacement.  I removed it and there was indeed a bit of toner dust behind and around the enclosure, but not quite enough to explain the lines.  I cleaned that out regardless but the lines are still present.  It's like the toner isn't getting cleaned off by the ITB blade.  I'm wondering if there's something out of alignment within the cartridge assembly itself that causes this much toner to be placed on the ITB in the first place.

Steve

[Repairatrooper]

As with all printers, make sure you are plugged into a properly grounded outlet that has no other high current drain items on the circuit such as air conditioners or baseboard/portable heaters.  The only time I have run into this issue it is either cartridges or the ITB that is the problem. What are the results if you print the PQ Quality test pages or a job consisting of color and more than 10 pages?

[user544]

Hello,

I assumed it was on a grounded outlet but rather than make that assumption I used a circuit tester to verify.  Indeed, it's grounded and polarity is good.  Related, I've had the printer connected in multiple locations, multiple buildings but the issue persists.

I printed a 13 page document with color and now there are no lines.  There is maybe a hint of a line on the first page, but that's only because I'm really looking for it.  By the second page there is no line.  This seems somewhat consistent with the issue that I've been pursuing.  The first few documents or pages of a multi-page print have the lines and then the lines go away. It's quite difficult to troubleshoot because I can make a change and print some test pages that come out clean.  Then I hear later that the lines are back.

Maybe one of the cartridges is depositing toner when idle or when the unit calibrates or cools down?

Steve

[PSSG]

Recommend troubleshoot with toner cartridges removed:

1. Press the Home button.

2. Open the following menus:

● Administration

● Troubleshooting

● Diagnostic Tests

3. Press the Down arrow button to highlight Disable Cartridge Check, and then press the OK.

In this diagnostic mode, you can print with the toners removed.  Remove all toners and print a test.  Install toners one at a time and print a test.  This should identify any toner issues.  Toner issues usually do not self correct.

A cleaning blade scrapes the residual toner off the surface of the ITB. The residual toner feed screw deposits residual toner in the toner collection box.  Check this process.

I am a forum volunteer.  I do not  work for HP or speak for HP.

[user544]

Hello,

I had that in my initial message, that I did the diagnostic without the cartridges as one of the first troubleshooting steps.

Steve

[PSSG]

I appreciate the reminder.  If I understand your reported actions correctly, the printer has had the same print defect with two different belts and two different sets of toner.  If you ran the disabled cartridge tests for both sets of belts/toner and could not identify a hard solution, I am stumped.  I do not have a resolution for your printer's problem.  Good luck.  May your troubleshooting be successful.