Envy 7645 prints with horizontal white stripes

[FixerCharles]

Envy 7645 prints with horizontal white stripes or bars. They are intermittent and of varying width but uniform spacing. I have read a number of threads related to this problem and tried many of the suggestions. As an experiment I printed out a page with a diagonal crosshatch pattern. I wanted to discriminate between a nozzle problem and a paper feed problem. The result showed that the problem was caused by overadvancing the paper between passes of the printhead. The diagonal lines matched if the gap was closed. Also, and possibly related, the printer has frequent paper jams. The printer halts mid-page and sounds an alarm, but the paper doesn't appear to be actually jammed, it is moving through the paper path normally. It just stops. I have cleaned the rubber rollers with no effect. There appears to be a small diameter "platen" with associated small plastic rollers positioned immediately before the printhead in the paper path. It is obvious that this assembly must be responsible for the fine positioning of the paper as it is moved under the printhead. Why would the paper be moved too far for each pass of the printhead? What sort of repair is needed?

[A4Apollo]

Hi! @FixerCharles, Thanks for stopping by the HP Support Forums!

I understand when you print from your printer the printer is printing horizontal stripes.

Don't worry I'll try to help you out.

Did you make any changes to your printer?

Have you tried checking with a different ink cartridge?

Does the issue persist when you make a copy from your printer?

Have you tried printing from a different application? Does the issue persist?

Excellent description and a great diagnosis done. It is greatly appreciated.

Replace low, empty or faulty ink cartridges on your printer.

If the copy works fine try the steps recommended to uninstall the printer drivers from the root level on your PC and install the full feature printer drivers and check if it helps.

In Windows, search for and open Programs and Features.

Select your HP printer.

Select Uninstall.

In Windows, search for and open Devices and Printers.

In the Devices and Printers window look for your HP Printer. If you see it listed, right-click on it and choose "Delete" or "Remove Device.”

Open up the run command with the "Windows Key + R" key combo.

Type printui.exe /s and click OK.

Click on Drivers tab.

Look for HP Printer driver. If you see it click on it and click remove at the bottom.

Select OK.

Update the full feature printer software using this link. Click Here

Clean the ink cartridges

Follow these steps to clean the ink cartridges from the printer control panel.

NOTE: 

To avoid issues that require cleaning, always turn the printer off with the Power button.

1. Load U.S. letter or A4 size, unused, plain white paper into the input tray.

2. On the printer control panel, swipe the display to the left, and then touch Setup.

   The Setup menu displays.

3. Swipe the display up, and then touch Printer Maintenance.

4. Touch Clean Cartridges.

   A Print Quality Diagnostic report prints.

5. Examine the Print Quality Diagnostic report.

   • If the print quality is unacceptable, touch Proceed when prompted to continue the next level of cleaning. Repeat these steps for the third cleaning stage, if necessary.

     NOTE: 

     If the printhead is badly clogged, it might require another cleaning cycle. If so, wait 30 minutes before you perform all three levels of cleaning again.

   • If the print quality is acceptable, touch Done when prompted to continue the next level of cleaning. You do not need to continue troubleshooting.

6. Examine the print quality on the Print Diagnostic report.

Refer this article to further troubleshoot print quality issues. Click Here

If the issue persists try running print and scan doctor on your PC and check if it helps.

Refer this article to know more information about using HP print and scan doctor.

Let me know if this helps!

Have a wonderful day ahead! 🙂

Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.

Click the “Kudos, Thumbs Up" on the bottom right to say “Thanks” for helping!

[FixerCharles]

Thank you for the reply. I'll try to answer your questions somewhat informally. The ink cartridges were replaced by the onwer based on speculation that they might be the problem. The printer had been in service for possibly a couple of years. I have observed the problem in every printing context, including copying, printing (both from Windows and Linux), and also printing internal status documents. I have "reset" the printer by unplugging it from AC while it was on.  I have done quite bit of Google research to see if I could find insight into the problem. I have reviewed many posts that describe what I am convinced is the same problem, and followed suggestions in some of them. This includes suggestions by HP employees which are similar to the ones in your response. None of the forum posts that I encountered contained an answer to why the malfunction occurs, but I surmised that the problem is not particularly rare in this family of printers. As I said before, I have closely examined printed documents and found that the image would line up properly if the gap did not exist. I have noted that the uniform spacing between the bands corresponds to the height of the printhead. It seems clear to me that the correct explanation of the problem is that the paper moves too far between passes of the printhead. The most likely cause is a mechanical defect in the paper control subsystem. It could not be caused by a driver problem or a printhead problem. It is inconceivable that there is no awareness on the part of the engineers of the susceptibility of the design to this kind of (very premature) failure. It occured to me that the repair may not be trivial in terms of the necessary disassembly and I would be surprised if the parts and technical information is even available outside of HP. My original question pertained to what is the cause of the problem, and how it can be repaired. I also would ask where am I right and/or wrong about my analysis of the issue. Thanks again for your attention to my problem.

[The_Fossette]

@FixerCharles,

It is great to have you back and your patience is greatly appreciated.

I am sending you a private message suggesting the next course of action.

Please check your private message icon in the upper right corner of your HP Forums profile.

Good day! Take care 🙂

Cheers!