HP Color Laserjet Enterprise M750 Printing Grey Horizontal Lines Again

[CJLANDRY]

Hello, 

I last contacted this forum in September 2019 concerning an ongoing issue I am having with my HP Color Laser Jet Enterprise M750.  In July 2019 the printer was printing faint grey lines horizontally across pages.  I changed the transfer kit, and this fixed the problem until September 2019 when the same grey lines started to appear.  At this point I changed the toner collection unit ( although it was not full ) and I cleaned out the Intermediate Transfer Belt (ITB) toner waste compartment at the end of the belt unit, it was full of toner.  I also wiped off the belt itself. This corrected the issue for a while but then I noticed the grey lines being printed again.  So for the past month or so,  I have been repeating the process of cleaning out the ITB toner waste compartment, wiping down the belt and then re-installing.  This allows me to print again,  but only for a short period of time before seeing grey lines again.

On printing the configuration page, the Fuser Kit interval is 150,000 with "Pages since last Fuser Maintenance 144,500".  The Transfer Kit Interval says 150,000 with "Pages since last Transfer Maintenance 119,000. 

I am wondering about the following:

(1) Is it possible that the toner is not being cleared properly from the ITB toner waste compartment, how would I know if it is not ?

(2)  Given the Configuration Page figures, should I be replacing the Transfer Belt Maintenance Kit at this point even though it says " ..last maintenance 119,000, not yet reached 150,000.

(3) Should I also replace the fuser kit now or wait for it to reach 150,000. 

Thanks for your help

[Repairatrooper]

Are the horizontal lines evenly spaced? Typically transfer belt issues result in vertical lines. Toner cartridges are the biggest contributor to horizontal lines. Can you run the Print Quality pages and post them here by any chance?

[Valsimot]

If the print on an A4 then transfer belt lines would be horizontal due to printer orientation in the paper tray, on A3 the lines would be vertical.

1) The main reason for lines caused by transfer belt is due to the cleaning blade that gets a piece of dust or something in the place where lines appear. The cleaning of cleaning blade would make your belt prin much longer without lines that cleaning the belt itself. Cleaning of the cleaning blade needs transfer belt disassembly and it's a dirty job because of waste toner.

https://community.spiceworks.com/how_to/132391-hp-m750-m775-transfer-belt-toner-build-up-and-how-to-... 

2) and 3) The page count of each part can be more than a 150 000, you will not need to replace fuser or belt sooner but it's recommended. In a case of defect fuser or belt, they need to be replaced sooner than recommended. Depending on the printer model some of them will stop when any part reaches 150K but I think that M750 can go beyond 150K for each part without any problem.

[CJLANDRY]

There was just one line 1/2 " up from the bottom of the page.  Since my message, the problem resolved itself.  I had changed the black ink cartridge and experienced the horizontal lines at the bottom of about 100 pages and now there are no more lines for the last 1500 pages or so.  So I am hoping that this will continue for some time.  If it starts again I will run a Print Quality page and send it your way.  Thank's for your guidance

[CJLANDRY]

Valsimot, 

Thanks for your advice,  I took a look at the link you provided and it was very helpful.  You mention "cleaning the cleaning blade", and I am wondering where to find the cleaning blade so I can clean it ?

Regards