my printed document print really light when using black ink
You do not state what type of printer you are using or what you are trying to print. This would help anyone trying to help. However,
My wife has the same problem with her printer if she forgets to use it.
If you have an inkjet printer the problem can be seen when the BLACK INK cartridge is empty or blocked. cleaning can sometimes help. You should always use an inkjet printer at least once a week to keep it printing well. Print both in colour and black text.
I have a ink jet printer.