Using 'patch' smudges fonts

Hello All,

I know it becomes a bit tricky in general (gathering from previous related posts) when one uses the 'patch' command. The default vectors renderer Painters gets changed to OpenGL. I searched if this question has been answered before, but couldn't find any satisfactory posts. So, here goes:

The problem I am facing is that when I use 'patch', the fonts of the axes get smudged. For comparison, I have attached two plots, one using 'patch' (Patch1.pdf) and one without (Patch2.pdf).

Any ideas on how to correct this? That is, get the fonts in better quality?

Thanks!