This morning my 7645 only spits out blanks.

[onnyjittspa]

hp7645 no error messages

[sandytechy20]

@onnyjittspa

Welcome to the HP support community.

Did you make a copy and check if that comes out fine?

If not, follow the below steps:- 

Clean the ink cartridges

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.

You can refer this HP document for more assistance:- Click here

I hope that helps.

To thank me for my efforts to help you, please mark my post as an accepted solution so that it benefits several others.

Cheers.