CP6015 Calibration marks ghosting on prints

[MvanderPol]

On my CP6015 I am getting a band of dark smudged color along the the far edge of the paper. Far edge is the edge towards the back of the printer, and only on sheets that physically traversed the far side. Paper that was going through in the middle ( like rotated letter, or legal, or any size under about 10" wide ) prints fine, so the defect is someplace fixed in the bowels of the machine.

CP6015 Calibration Marks Ghosting on prints.
If I print enough sheets, it eventually fades and clears up - on the printer I do a few PQ Diagnostic prints that put out 9 pages with quite a bit of toner coverage and these show pristine quality except for the band along the top of those pages, independent of the toner being tested. So two or three PQ Diagnostic jobs can do the trick. But uses paper and lots of toner.

I got a new ITB a while ago, and it cleared up - for a while. Then it returned. The next diagnostic I tried was to examine the ITB after a print showed the defect - and on the ITB there was toner in a band in the place it was showing up on the print. With hindsight that should have been enough to give me all the information I needed to get to the final conclusion, but I am not an laser printer expert - I just use them and try to keep them running. If I clean the belt ( and rotate it to expose the whole band of the left over toner ) it will print fine again. For a while.

I changed the secondary transfer roller, which also looked dingy in the same region - I was thinking the toner had collected in the roller and was contaminating the page there. 

Also not a permanent solution.

I got a new ITB wiper blade from a parts supplier in China - no idea if it was OEM or a knock-off. It was an interesting exploration to figure out where it actually needed to be fitted as there was no information on any process or what to disassemble. But give me a screwdriver and a vague notion of where to start I'll figure it out. So I got to the wiper/cleaning blade - there was a lot of waste toner that got dislodged when I disassembled the collector and collection screw - so much toner - all over the machine, the bench I was on, and on me... anyhow, it occurred to me that all that toner was the problem and somehow it was not being squirreled away and just sort of accumulated in the wrong place. So I cleaned it up and shook the toner out the chamber under the belt where it accumulates - through the little channel into which the collection screw dumps the waste toner. I don't know if there is a procedure to open the bottom of the ITB assembly, but nothing was apparent to me without going into much further disassembly than I was willing to pursue at the time.

That also cleaned up the issue for months, but eventually it came back. 

Among other things that were done was to replace the fuser, and I found a couple of latches that had broken for which I found some spares, but those didn't make a difference, either.

In desperation I re-installed the original ITB which I'd kept - just in case - and the issue cleared up like magic!

Finally, problem solved - somehow just jiggling ITB around made a difference, or dislodged whatever was out of alignment, or something.

But the newly re-installed original ITB also started showing the same issue, again.

I'd read somewhere from forum posts here that this issue has been observed on other CP6015's and the pattern is an artifact of the calibration process which apparently deposits toner which is scanned to provide feedback for the process. It should be cleaned up and never show up but it matched the pattern I was seeing. 

Anyway, this time I was printing the PQ Diagnostic pages from the manual feed tray 1,  just to add another variable to see if I could provoke different behaviour and there was a massive paper jam, and the job was aborted - the pattern hadn't cleared yet on the pages that did print - so I pulled out the ITB and prepared to clean the waste toner screw and collection again - now down to a 10 minute process for me - and on the ITB top surface was an image of a diagnostic page of the PQ Diagnostic sequence - it had not been transferred to the paper yet - the printing had stalled mid-process. But as I turned the ITB not all the toner was being scraped off. Some places there were clear bands where the scraper had squeegeed all the toner, but in other places it had just smeared the toner. I tried pressing on the bar that holds the scraper and I could influence how much pressure the scraper exerted on the belt and this altered the pattern of the smearing and even caused it to clear properly in places... the penny finally dropped - the belt top surface should always be pristine as it is after the scraper has cleaned excess toner off. I am sure seasoned printer techs are shaking their head by now, but as I said, that's not me. So I took the scraper off altogether, and while it had some toner on it, it looked clean enough. But I took my lint free cloth and gave it a good clean, and put it back on. It improved but did not quite do a complete job when I manually rolled the transfer belt past the scraper.

So I took it off again and this time used a coarse paper towel to give it a good scrubbing and rubbing. And when I put it on again, now when I turned the belt under the scraper, it made a squeegee noise, that high pitched whine as it rubs over the surface - not that I'd ever heard a ITB make that noise, but when I use a squeegee on other glass or screens, that is the sound I hear when I know I am getting a good edge on the surface and removing everything on it. And indeed, as   rotated the belt under this cleaned scraper, it squealed AND all the toner was completely removed from the belt. I could see it accumulating against it, and could imagine once re-assembled how the waste toner screw would pick up that excess toner and move it to the waste toner gate and into the waste reservoir under the ITB.

I assembled it all back into the printer, and indeed, the calibration marks were gone, and the printer has been performing perfectly since then.

I now have a relatively quick process to tackle this problem if it show up again - and I suspect it will - which is to take out the ITB, remove the waste toner collection cover and collection screw - on a toner tolerant surface as there will be lots of toner spilled in this process - and get the scraper off the belt and clean it, thoroughly. Clean up the toner, of course, and re-assemble. If the belt squeals after this is done as you manually turn it, proper contact is achieved and you should be back in business.

My speculation on what is going on - the calibration process places a toner pattern on the belt that is examined by a sensor as the belt is advanced under it. The toner is intended to be removed by the scraper and the process completes. For whatever reason, on my printer, and others judging by the reports and forum posts I see, this band of calibration toner stops being cleaned off and remains on the belt and subsequent prints are overlaid on the left over toner and show up in the print. Not sure why it eventually fades.

This one inch of the scraper is continuously taxed with a band of toner never intended to be picked up by paper as part of the regular calibration cycle. The scraper's normal job is to pick up remnants of toner that didn't transfer to paper under the electrostatic charge so should be minor amounts. But in the area of the calibration band, there is a lot more than that. And the pristine scraper can cope with it fine - but it always right there in the same spot. I suspect perhaps over time particles of toner get pushed under the edge of the scraper and accumulate and lift it up of the belt. This accumulation will continue and eventually lifts the scraper far enough that toner stays on the belt - perhaps it fades as successive pages pass over it and enough transfers to the paper to clean it up.

I also noticed when the paper jam happened and left a whole page image of toner on the belt that the scraper failed to remove the toner at first, but did when I had thoroughly cleaned it. So the condition of the scraper is significant and for whatever reason deteriorates. It is in contact with the belt at all times, and is under tension to maintain a constant pressure of the scraping edge against the belt. Perhaps different environmental conditions impact its pliability, or malleability. Or cold toner or warm toner sticks differently to the belt which impacts how it is scraped off.

Anyway, apart from that anomaly, this printer is going strong and when the next instance of the calibration marks show up I can apply my streamlined cleanup process and get back into production in the time of a drum change.

If you are not comfortable doing that procedure, replacing the TLB is also a method to solve this problem - but they're not cheap. And if you're still hanging on to this printer, you've probably already done a fair bit of maintenance on it over the years - this will allow you to enjoy this workhorse for a while longer.

I am going to add edits to this post as I find other related issues here.

https://h30434.www3.hp.com/t5/LaserJet-Printing/HP-Color-LaserJet-CP6015-color-band/m-p/7089584

https://h30434.www3.hp.com/t5/LaserJet-Printing/Horizontal-streaks-on-top-and-bottom-of-printouts-go...

https://h30434.www3.hp.com/t5/Printer-Ink-Cartridges-Print-Quality/How-do-I-change-the-wiper-in-an-H...

https://h30434.www3.hp.com/t5/Commercial-Technical-Escalations/IPG-LASERJET-CP6015/m-p/5178502

https://h30434.www3.hp.com/t5/Printing-Errors-or-Lights-Stuck-Print-Jobs/CM6040f-MFP-Horizontal-Band...

[MvanderPol]

So while cleaning the ITB waste toner collector and the scraper, clears the issue for a number of prints, sometime a week or longer, it comes back.

I've now obtained an aftermarket belt scraper and installed that, and it also clears up the issue, which so far has not resurfaced. 

I was also puzzled why this item was offered in 5 packs, but if a scraper wears out or loses its edge, it is a simple fix to replace one, and cheaper than a whole new ITB - like it is a user replaceable consumable, perhaps...

Meanwhile, two other issues have emerged - 

1. I got a brand new ITB and it has a failure mode of tearing images like the charge wont stick to the belt or something like that.

2. During this diagnosing I needed to replace the black toner, and now I am getting blotches of random toner splatter on the printed page - fused, so it gets on the paper before fusing, but also it looks like on top of the color toner. 

Anyway, I'll start separate threads for those issues so as not to cloud this one.

[Meghana_10]

@MvanderPol, Welcome to the HP Support Community. 

Thanks for reaching out about your query regarding the HP Color LaserJet CP6015dn Printer.

We're thrilled to have the opportunity to assist you and provide a solution. We hope our assistance has been helpful! 

Ghosting, where previous images or text appear faintly on prints, can occur occasionally with the HP Color LaserJet CP6015 Series. This problem might be linked to issues with the printer’s calibration settings or internal components.

To address and troubleshoot ghosting issues, check the following:

1. Perform Regular Maintenance: Ensure that the printer undergoes routine maintenance checks, including cleaning and calibration.

2. Check and Clean Internal Components: Inspect components such as the transfer roller and drum to make sure they are clean and functioning properly.

3. Firmware Updates: Make sure that the printer's firmware is up to date, as updates often contain fixes for known issues.

4. Use of OEM Supplies: Ensure that you are using genuine HP toner cartridges and maintenance kits, as non-HP supplies may contribute to image quality issues.

5. Calibration: Perform a calibration through the printer’s menu to improve print quality and resolve ghosting issues.

I hope this helps!

Take care and have an amazing day! 

If you would like to thank us for our efforts to help you, go to the public post and give us a virtual high-five by clicking on "Yes" for the question "Was this reply helpful?" below my message, followed by clicking on the "Accept as solution" on my public post.

Regards,

Meghana

[MvanderPol]

The reply is generic and does not address the core issue.

Regular maintenance, cleaning, calibration are handled by the printer under normal operating conditions. Firmware updates might have been a useful response back when updates were being released, but last one I can find is 2018. And where possible, I always use OEM - the cleaning blade, for instance, is NOT as that is not a part I can order from HP.

I appreciate the effort, and it is an older model, (but only 10% through its rated life) so expecting more is fruitless.