By default all specific printer name settings are stored inside file "*\Clients\webserver\printer.bin"

Here example
PRINTERS=PS:%DEFAULT%%PRINTMENU%MS Publisher Imagesetter%Universal Printer %;PS:%PRINTHIDE%MS Publisher Imagesetter%Hidden Menu Virtual Printer %;

1. PS: = says it is PostScript format of driver
possible are PS: PostScript
 XPS: XML Paper Specification - Microsoft's format
 PCL6: Printer Command Language
 PDF: Adobe's format
which but require supporting format converter and printer driver.
In example %MS Publisher Imagesetter% is PostScript driver.

2. %DEFAULT%%PRINTMENU% = tells it should be default chosen printer and printmenu tells 
to display generated pdf content.
Possible are following values
 %DEFAULT% => allowed to be set only once by one printer, do not set it twice or more!
This setting makes printer default. 
Remove this tag by all simulated printers to use systems default preferences.

 %PRINTMENU% => display pdf window, should not be mixed with printhide since excluding 
each other in parsing sequence!

 %PRINTHIDE% => hide pdf window, requires browser with pdf mark support 
else print popup will never fire, as example Safari Mac does not support it.

 %PRINTMARK% => by default activated on printmenu/printhide. 
It is auto print popup mark of PDF language.

 %NOCONVERT% => provides printer data without converting to PDF format.

 %FORCEUNKNOWN% => skips print file format check, for mixing with noconvert.

 %EXTRA_OPTS([extras])% => extra options passed to converter attached on start
Example: %EXTRA_OPTS([%nopdfmarks%])% would forcibly 
disable print mark passing to PDF converter. 

 %JOINDELAY(1000ms)% => concatenates prints to one file if new print arrived 
in lesser than given time in milliseconds. 
 PS:%PRINTMENU%%JOINDELAY(4000ms)%MS Publisher Imagesetter%Next Universal Printer %;
That example will postpone print converting for at least 4 seconds.

3. %MS Publisher Imagesetter% = tells to use default Microsoft printer driver, you may choose here any printer driver present on server but be aware that such printer driver is compatible with converting program, "MS Publisher Imagesetter" is PostScript format driver. Microsoft does not accept all drivers to be used for printing conversion.

4. %Universal Printer %; = tells how the printer should be named when displayed inside RDP session in available printer menu. Notice, all wished printers are separated by semicolon ";" as in example on top. 

PS: remember, the name of printer displayed in session gets automatically attached in string (redirected *xyz*) and can not be controlled from client side.

IMPORTANT: restart HTML5 server in AdminTool GUI to take changes effect after any printer.bin update! 

UPDATE: on latest TSplus updates to get highest compatibility with all browsers that do not have support of PDF auto print popup mark the default setting in "*\Clients\webserver\printer.bin" is to display PDF frame anyway with %PRINTMENU%, to change it just replace that setting by %PRINTHIDE% and restart HTML5 server in AdminTool GUI!

Important notice :

The svcac.exe module of TSplus might reset the printer.bin file.

Therefore, after editing the file, you will have to set the file's properties to "Read Only" and save.