Why does using a Canvas object to print via Citrix sometimes result in extremely large print files?

Why does using a Canvas object to print via Citrix sometimes result in
extremely large print files?

I have a Windows application running via Citrix on Windows Server 2008r2.
When printing via the Citrix Universal print driver to certain printers,
very small text documents balloon up to greater than 67MB in size per page
in the print queue on the client machine. The code currently is using a
TCanvas object to draw to the printer. Switching to just sending the data
to the printer in a raw fashion to the printer handle does make the issue
go away, but it also introduces other issues. Is there any way to continue
to use TCanvas for printing and not have the large print files?