The Windows spooler service can be enabled in the new full Windows Docker images of the latest Server 2019 Insider builds.
$ docker build --isolation hyperv --no-cache -t print .
Sending build context to Docker daemon 2.048kB
Step 1/4 : FROM mcr.microsoft.com/windows-insider
---> 09a59f60f394
Step 2/4 : SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
---> Running in 59680f017c12
Removing intermediate container 59680f017c12
---> 94bce0226b5e
Step 3/4 : RUN Set-Service -Name spooler -StartupType Automatic
---> Running in 2dc61f761ef5
Removing intermediate container 2dc61f761ef5
---> c18e54ae08a3
Step 4/4 : RUN Get-Printer
---> Running in a843b0293503
Name ComputerName Type DriverName
---- ------------ ---- ----------
Microsoft XPS Document Writer Local Microsoft XPS Do...
Microsoft Print to PDF Local Microsoft Print ...
Fax Local Microsoft Shared...
Removing intermediate container a843b0293503
---> 6347e0cdb9e9
Successfully built 6347e0cdb9e9
Successfully tagged print:latest