C-7250 HP all in one appears to have a stopped up printer head?

if the ink is new then you will have to run a head cleaning program on the printer ( did you remove the sticker from the top of the new inks )

under warranty get help from a warranty call from an authorized service agent

INK PROBLEM
Inkjet printers need to be used frequently to prevent inkdrying out and blocking the print head nozzles.
If the print head cleaning maintenance routine does not clear the blockages,then print head needs replacing, but it may be expensive.
It may be more cost effective to buy a later model and better printer thanreplace the print head.

How long was the printer stored before you took it out to use it? You can't store a printer with or without ink cartridges in it. When a printer sits, the ink that is in the print heads settles and dries. Once that happens, the print heads are pretty much ruined. You can buy new print heads, but its usually cheaper to buy another printer instead. The reason it is not printing is probably because the print heads are plugged.

Try cleaning the heads through maintenance of printer software this should help with this problem. I have the same printer and it fixed mine after go to hp solutions and then using the cleaning software with the printer.

Hope this helps.

Do the cartridges ride on the printing carriage, or do they plug in somewhere else in the machine and have hoses that run the ink to the print head? If they ride on the printing carriage and the cartridge is new, there could be a short in the printer and it needs repair. Check if there's ink smeared on the print head or part of the printer. Generously clean the print heads with lots of paper towels and rubbing alcohol. If that doesn't work, to see if it's an issue with computer, print a test page from the printer, but don't send the print job from the computer. You need a print job generated from inside the printer itself. Not every printer can do this, but try pressing paper feed, holding down paper feed and power, or holding down cancel and power. If the blue lines disappear then but they didn't when you cleaned the heads, it's a software issue.

Using HP Director, you should be able to check estimated ink levels by selecting Settings -> Print Settings -> Printer Toolbox and then clicking on the Estimated Ink Levels tab.

If the ink levels appear to be sufficient, on the printer control panel press Setup, 1, 4. This will generate a self-test report. If there is streaking of any of the 4 bars at the bottom of the page, the affected cartridge may need to be cleaned. If any of the bars are missing, the cartridge needs to be replaced.

To clean the cartridges, press Setup, 5, 1. This will print a page of patterns.

HP, in order to sell more ink, monitors the expiration date of the cartridges installed. Solution is either to buy a new unexpired cartridge from HP or to disable the date monitoring built in to the printer. This latter is done by removing the button cell located inside the D135 printer on the left hand side or by simply slipping a thin piece of plastic between button cell and metal contact. You will no longer have date function on printer, but it won't object to expired cartridges either.

Please try the following to resolved the issue:

Run a series of head cleaning
1. Make sure the printer is turned on but not printing. Make sure there are no error lights or messages appearing in the LCD.
NOTE: You cannot clean the print head if the any of the cartridges are expended. Replace the appropriate ink cartridge before proceeding.
2. Load letter size paper.
3. Click on START, CONTROL PANEL, PRINTER & FAXES then right click on CX3200 printer Icon then select printing preferences
4. Click on the UTILITY or MAINTENANCE tab, then click on HEAD CLEANING.
5. Follow the instructions on the screen to clean the printhead. Cleaning takes about 30 seconds, during which time the printer makes some noise and the power light flashes. Never turn off the printer while the power light is flashing, unless the printer has not moved or made noise for more than 5 minutes.
6. When the power light stops flashing click PRINT NOZZLE CHECK PATTERN and then click NEXT.
7. If the nozzle check pattern has no gaps in its lines, click FINISH. If the pattern has any gaps, click CLEAN to clean the printhead again.
8. If the situation continues after three cleaning cycles and nozzle checks, replace one of the affected ink cartridge(s).
9. Once the cartridge(s) has been replaced, please follow steps one through seven up to three times.
If the nozzle check still has gaps after you have run at least 3 consecutive cleaning cycles and replaced the affected ink cartridge(s) with genuine Epson inks, your printer will require service.

Sometimes a cart doesnt work well because of mal manufacturing. Put in another brandnew black cart and do the cleaning cycle again. Its an advantage to use genuine brother carts! If you dont have any success try this: press menu then start/mono (b/w) then four times arrow up. maintenance should be displayed and the printer beeps. press arrow up til 7 is displayed. press enter. press arrow up til 6 in display. press enter. Display: Cleaning_All. press arrow up til 3 then enter: power_p all. Press start mono. machine starts power cleaning. After maintenance is displayed press arrow up til 0 (zero) then enter then 9 then enter. machine prints print quality sheet. In case there are only a few blocks in black repeat the above procedure. If you doesnt see neither any blocks in bk nor text after the second try be sure that your printhead is clogged and cant be cleaned anymore. This happens due to thirdparty ink which has pigmented ink instead of dye ink. Use only dye ink for brother printers!!!