Icing Bleeding into my Royal Icing Transfers

I have not encountered this problem - yet.  When your transfer sets/hardens turn over and let the bottom air dry too - about an hour (?).  You can use a  fan or  heat lamp but I wouldn't use it until after I am finished with the transfer.  Either one will also dry your RI base on the cake.  I'm inclined to let the cake air dry though.  If need be then I'd use a fan or lamp.  My  table lamp will crust my icing before I'm finished..., so I tend not to use while decorating...  To me the base has to be dry too, otherwise there is too much moisture.  I am guessing but let the cake dry overnight then using minimal RI onto your transfer or the cake top place your transfer. 

thanks,

is that means i should use a fan to make the base dry faster??

You stated that your base is not completely dry.  It should be dry, air dried.  You should crust coat the cake, let it air dry, then apply the second coat, let it dry.  The RI shouldn't have a lot of water n it.  Do your transfer in sections, let them crust - or completely dry, before doing the next section/s.  Some let each section crust before continuing on to the next sections.  A fan will help crust and air dry.  It doesn't seem to me that you are doing wet on wet, that you have definition.  Did you moisten the cake so that it doesn't dry out (additional moisture)?  If so, cover it and put in the refrigerator to keep the cake from drying out.  Take it out and let it sit, touch with your finger to see if it's tacky.  If so, wait before applying RI.  Did you cover with fondant before applying RI?  If you covered with fondant that too must air dry before applying RI.  In any case though you must ensure that the cake is moist and not dry.  Your RI should be hard, hard enough that if you your take off point has a bump that you could scrape it smooth with a knife.  When it is hard dry, put medium consistency on the bottom of your transfer and put on the cake.  Make sure that RI doesn't seep out from underneath.  You don't need a lot of RI.  (I got the table lamp so that I could see but found it was crusting my RI before I was finished.  The brand name is Ott.)  I hope I am clear in what I typed.  Hopefully others will chime in... 

i understand now,thanks
Your explanation is very clear

It's too bad that no one else commented.  I hope I didn't give you any misinformation. 

you are right, 

when i rend the baking sheet,

my transfers still soft and have sponge texture at the back side 

i turn around and let it dry few hours,

it become hard and the color back to solid color

I generally make fresh cream cake,
so the cream's moisture may make my transfers wet,

I will put my transfers on the cake when i serve it to my friend (keep away from the refrigerator's moisture) and take photo quickly,,XD

but i think it would to better if i make it on the cookies or chocolate, then put it on the cake.

see my final cake~