I have an HP Officejet Pro 6978. I left it inactive for 6 months, now it won't print in color

[Annieo1]

I left my printer for 6 months. I removed the cartridges and put them in an airtight container as directed by HP. When I returned I put them back in but couldnt get it to print. I installed a new black cartridge and cleaned the head a number of times. Finally it printed in black. I installed new color cartridges and it still won't print or copy in color. What can I do? I have already spent more on cartridges than I did on the printer!

[Jeet_singh]

@Annieo1,

Thank you for showing your interest in HP Support Forums. It is a great place to find the help you need, from other users, HP experts, and other support personnel. I see from your post that you're having issues while printing in color from your HP OfficeJet printer. Don't worry we'll work together to help you find a solution. 

To provide you with an accurate solution, I'll need a few more details:

Have you recently made any changes before the issue started?

Did you try to update the printer firmware? Have you tried to align the cartridges?

Have you tried to check the print settings?

Have you tried to print the print quality test diagnostics report or print the self test page.

In the meantime, let's try these steps here: 

Let's start off by updating the printer firmware. If your printer connected wirelessly, make sure to temporary connect the device with USB and then follow the link to install the latest firmware update on your printer from our HP support website. Alternatively you can also try to update the printer firmware directly from the printer control panel.

For more details on how to update, please use this link: HP Printers - Updating or Upgrading Printer Firmware

If the issue persists, I would suggest here is to do a hard reset on the printer and make sure that the printer is connected directly to the wall outlet and not to the surge protector.

With the printer turned on, disconnect the power cord from the rear of the printer and also unplug the power cord from the wall outlet.

Remove USB cable, if present.

Wait for 2-3 minutes, press and hold the power button on your printer for about 30 seconds to remove any additional charge.

Now plug back the power cable straight to a wall outlet without any surge protector or an extension cord and then plug back the power cord to the printer.

Turn on the printer and wait till warm-up period finishes and the printer is idle.

Next thing, I would suggest here is to print the print quality diagnostic report from the printer. 

For more details, please follow the steps suggested in the support document for - HP OfficeJet 6900 Printers - Black or Color Ink Not Printing, Other Print Quality Issues

Could you please respond to this post with the details and with the results of the troubleshooting as this will help me in further assisting you.

Eagerly waiting for your response!

that said, If the information I've provided was helpful, 

give us some reinforcement by clicking the solution and kudos buttons, 

that'll help us and others see that we've got the answers!

Good Luck.

[Annieo1]

Thank you for your suggestions. I had updated the firmware and a number of other of your suggestions. What finally worked was doing a hard reset. 

Does the printer need to be plugged into the wall always? We get a lot of power surges and I had previously had it plugged into a surge suppressor to protect it. 

[Jeet_singh]

@Annieo1,

Thank you for the update,
I appreciate your time and efforts, 

I'm glad I could contribute towards resolving the issue and finding the solution you were looking for.
Thanks for taking the time to let the community know about the solution.

You've been great to work with and it has been a genuine pleasure interacting with you.
I hope both you and your product works great and remain healthy for a long time 😉 

To simply say thanks for my efforts to assist you, please click the "Thumbs Up" button to give me a Kudos.
And mark my public post as Accepted Solution to help others find a similar solution as you have.

Take care now and do have a fabulous week ahead. 🙂
Regards,