Hi
Welcome to HP Forums, this is a great place to get support, find answers and tips.
Thank you for posting your query. I'll be more than glad to help you.
I understand that you are facing issues with your HP Officejet 5740 All-in-One Printer wherein it does not print in color.
This issue could occur if the cartridge contacts are not clean or the nozzles may be clogged or the cartridges may be defective.
Let's go through a few steps that may help to fix this issue.
And here are a few steps in the link: Print Quality Issues
If the issue still persists, please contact HP phone support from this link: www.hp.com/contacthp
You may select the country and type the product# of the unit and then follow the on-screen instructions to contact HP phone support.
You have a good day ahead.