What ink does HP 640 fax use?
HP 701 Black Inkjet
This fax machine uses HP 701 Black Inkjet Print Cartridges.
Can I use my HP printer to fax without a phone line?

Do I have to have a phone line to use Mobile Fax? No, you only need an internet connection to use Mobile Fax. Can I receive a fax without a fax machine? No, HP Mobile Fax only supports sending to other fax machines.
How do I get my HP printer to fax?
Go to File, then Print, and Printer to select the printer output. You will be presented with several options, but you will select the one that has “Fax” in the name. Click Print, which will open a new Send Fax window. Enter the fax number you wish to send the document to, and update the settings.
How do I put ink cartridges in my HP Officejet 640 fax?
Replacing the print cartridges

- Step one: Remove the old print cartridges. Verify that the unit is on. Press the Start/Enter button to turn on the unit.
- Step two: Install the new print cartridge. Open the package.
- Step three: Align the new print cartridges. Press 1 since this is a new cartridge.
Can I fax myself?
You can also use a variety of free internet faxing tools to send yourself a fax without a second fax machine. FaxZero is a free, ad-supported service that will let you upload a file and fax it to a fax line of your choice.
Why isn’t my fax working?
If you find your fax not working, it could be due to the following reasons: The fax number you’re trying to send your fax to is busy or unreachable. You are trying to send a fax to a number that is blocked or outside your area code. Your fax machine could not establish a connection with your telephone line or modem.
Can you fax with WiFi printer?
If you have a WiFi multifunction printer, the only way to use it to send a fax is by scanning your document and then sending your document via an online fax service like eFax.
Why won’t my fax machine send or receive faxes?
Can I fax through WiFi?
Yes! Using an online fax service makes it easy to send faxes via WiFi. You’ll use a simple online portal to send your fax or ping it to someone by email. All you need is a WiFi connection.
Do I need a landline to fax?
Fax machines (and computers with fax software) need a landline phone line to fax. VoIP & internet phone lines are not compatible with a fax machine (or computer with fax software). An online fax service does not need a phone line. It lets you send and receive a fax over email or the web.
What are the steps to follow when replacing the ink cartridge of a printer?
Place the ink cartridge into the cartridge holder with the bottom down. Then push down the ink cartridge until it clicks into place. When you are finished replacing cartridges, close the cartridge cover and the printer cover. The printer moves the print head and begins charging the ink delivery system.