HP Photosmart 7550
Magenta and Yellow wont print. Black, photo black & cyan print

Experienced technical support provide their insights in answering this question :
Remove the color cartridge and do a “blot” test by pushing the heads on the bottom onto a paper towel. You should see all the colors. If not, then run hot tap water on the heads. Could be a bad ink cartridge if it still doesn’t work.

How to Identify and Fix Common printer Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced technical support :

Reasons why your HP printer has ink but won`t print

This may seem obvious, but it sometimes happens: first make sure your paper tray has paper in it. Misalignment, clogged printheads, faulty data communication or insufficient ink levels can also be sources of the problem.

Verify the ink cartridge(s) is inserted properly. Some cartridges snap in place, and if they are not inserted fully, the printer won`t print anything. If a lever is moved from its original position to allow for installation of ink cartridges, ensure it is returned to its original position.
Even if your cartridge is full and ready for action, it may have become slightly dislodged and no longer in full electrical contact with the printer. The easiest way to rectify this potential problem is to simply remove and reinstall the cartridges.
The reason may be quite simple – your cartridge is dry or clogged. Still, adding fresh ink may not resolve the situation. Try to wipe the cartridge with a lint-free cloth dampened with isopropyl alcohol. Please avoid touching the metal parts of these cartridges and the chip not to damage their electrical contacts.
Just above the circuit board on most printer cartridges, you`ll find a small button. You`ve seen these tiny buttons before on cell phones, phone chargers, etc. This is your reset button, and the only way to get in there is either with a paper clip or the tip of a pen (which will leave a tiny ink smudge on the button).
There are a number of reasons why ink is not flowing through the cartridge, despite there being plenty of ink in the cartridge. The most common cause for this is infrequent usage. If your printer is not used on a regular basis, at least once a week, the cartridge can dry up and then become clogged as a result.
If the ink level is sufficient, but the printer still does not print black ink, you may need to run a cleaning cycle. A cleaning cycle is a process that cleans the printer heads and removes any clogged or dried ink.
Several factors may cause the product to print blank pages, such as print settings, low ink, or the product itself. Check the following: Make sure the product is placed on a flat, stable surface that extends beyond the base in all directions. The product won`t operate properly if it`s tilted or at an angle.
Running out of ink

If your printer runs out of ink, obviously the pages will come out blank when you attempt to print out what you need. Most of your HP printers will already have some kind of indicator to let you know that you are running slot. Solution: The solution is a no-brainer. Replace the ink cartridges.

Printers that use two cartridges (one black, one tri-color) can print if one cartridge is empty. To continue printing, remove the empty cartridge from the printer. If a Single-cartridge mode message displays, select OK. If you are using the black cartridge, prints are in black and white (grayscale).
Several factors may cause the product to print blank pages, such as print settings, low ink, or the product itself. Check the following: Make sure the product is placed on a flat, stable surface that extends beyond the base in all directions. The product won`t operate properly if it`s tilted or at an angle.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Ink Problem
ANSWER : Remove the color cartridge and do a “blot” test by pushing the heads on the bottom onto a paper towel. You should see all the colors. If not, then run hot tap water on the heads. Could be a bad ink cartridge if it still doesn’t work.

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HP Photosmart 7550

Photosmart 8250 ink system failure problem??
ANSWER : To anyone looking for the firmware file

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HP Photosmart 7550

Epson 7880 ink pump sucking ink
ANSWER : Not ink pump, but air pump, to put the ink feed under pressure.

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HP Photosmart 7550

EPSON Stylus NX400 Vista Print Problem
ANSWER : I have the similar issue. The browse button would not open the connection listing the shared printer. How can I fix it? Please respond to this post or contact me via buy essays. Thank you in advance!

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HP Photosmart 7550

epson artisan 800 ink pad warning
ANSWER : how do i override the error

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HP Photosmart 7550

epson printer problems
ANSWER : My Printer Has A Internal Erro

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HP Photosmart 7550

Kodak ESP3250 Low Ink Warning – Over ride ??
ANSWER : kodak I’m buying new printer yours sucks…sorry but it does.

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HP Photosmart 7550

Oki C5300 problem : network menu disappeared.
ANSWER : You need MuWin and your NIC firmware to upload to the host, but both things are keep under cover by OKI… Find attached old (and probably useless for you) files; check and say.. (https://mega.nz/#F!oEkA3JKZ)By the way, you should specify what firmware do you need ¿isn’t it? I don’t know yet what firmware uses my c511dn nor what NIC host it mounts… :~(

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HP Photosmart 7550