duplex mode

вот описание сабжа для QReport

property Duplex : True

Applies to

TQRPrinterSettings, TQuickRepPrinterSettings

Description

Setting Duplex to True will case reports to be printed on both sides of the paper on a duplex enabled printer. This version of QuickReport will only print in the 'horizontal' duplex mode. Setting Duplex to True will force all printers to print on only one side of the paper.

See also

TQRPrinterSettings

Вопрос :
Что-такое 'horizontal' duplex mode ?
или
Почему принтер может не печатать в дуплексе, если я устанавливаю сабж в true ?
(через word печатает)