Hello, I have an HP Deskjet 2050 J510 series, I bought it 5-6 years ago, don't use it much and so far works fine BUT 

now , today I notice , even if on my screen everything is normal, when it prints thai letters, they are half invisible, what is strange is that when 

there are roman script every thing is normal , letters are easy to read

before, with this same print, I could print thai text as well, but no now 

Do you know what happens, it recognize thai letters but it can't print them in black, almost transparent 

I have to change my ink or change printer ? thank you for your help 

4 hours ago, Aforek said:

even if on my screen everything is normal

What program (word processor? text editor/viewer) do you use to create/print the Thai script?

What font is the text supposed to be written with?

 

What happens if you print a Thai website from your browser?

This is the WiKi article about Thailand in Thai language as an example:

https://th.wikipedia.org/wiki/ประเทศไทย

Just print one page.

 

I am asking because normally a deskjet printer is kind of a "dumb" system and the print is completely prepared by the software/driver of your device (is it a PC? what operating system?).

The printer "knows nothing" about the content that it prints (Thai, Chinese, Hebrew...).

I doubt very much that the printer as such (hardware) is a problem.

Step one: check the printer driver. Is it up-to-date?

 

Thank you for your response, I have found how to do it, it works well ( thai script is as visible as roman script )

with windows 10, PC, I want to incorporate thai script in a form written in roman script, pdf format

I use Xchange viewer, very good to write in pdf and I ask the printer to print in " photo maximum quality ", even if it's a normal paper 

it's very slow, but text is perfect ; I have other documents to print, now I  know how to do 

no need buy " Adobe acrobat", very expensive, here it's free