Very useful troubleshooting link from #matterhackers with example images.
I print PLA without a heat bed on my @Printrbot Simple with green tape I buy from a local hardware chain (RONA).
If there is enough surface and I clean the tape with rubing alcool I have a hard time getting the part off the print plate !
Its usually better to print on blue tape at 50C, instead. I suspect the issue is that you want some heat to reduce warping, but you don’t want it to contract so much on cooling that it grabs hold of the tape. I certainly find the tape easier to remove when I print on it at 50 than at 60.