Suddenly leaves narrow blank strip down center of page. Warked fine until now.

[Stopthetorture]

Was printing fine, suddenly leaves a blank strip about 2 spaces wide down the center of the page. 

[A4Apollo]

Hey there! @Stopthetorture, Thanks for stopping by the HP Support Forums! 

I understand when you print from your printer it prints a narrow blank strip down center of the page.

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

Did you make any changes to your printer?

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

Have you tried printing using a different brand paper?

Try the steps recommended below.

Check the print settings for your print job in Windows.
In the software application, you are trying to print from, click File, and then click Print.
The Print window opens.
Open the Properties dialog box.
Depending on the software application, the button might be Properties, Options, Printer Setup, Printer, or Preferences.
Depending on your print job, you might consider modifying the following settings:
Paper Type: If you are printing on photo paper, select the type of photo paper you are attempting to print on.
Print Quality: If you are dissatisfied with the quality of your printouts, increase the print quality. To print more quickly, decrease the print quality. These options typically include Best, Normal, and Draft modes.
Paper Size: If you are printing on a different size of paper than you normally print on, select the correct paper size.
Black and White: If you want to print in black and white only, select the grayscale option.
After selecting the print settings, click OK to apply the settings, and then click Print.

Refer this article to further troubleshoot print quality issues with your printer.

Let me know if this helps! 
Have a pleasant day ahead! 🙂

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[Copier-Pro]

I will try and help.This sounds to me like their is something in the toner cartridge not supplying toner in that area to the drum.I might be a small piece of paper or even just a hard piece of toner.

To test remove toner and shake it to one side while turning drum by hand if posible and see if you make a print if the line moved position.

Hope this helped.

[dav2-]

Purchased HPLaser Jet Pro M15w Printer White, Purchased via Amazon on 8 February  2019 Serial Number [edited]

has developed a fault for it leaves a blank vertical strip about 4 cms wide down the page . This is located about 4cms from the left edge of the paper