-SUBSYSTEM=="printer", TAG+="systemd", ENV{SYSTEMD_WANTS}="printer.target"
-SUBSYSTEM=="usb", KERNEL=="lp*", TAG+="systemd", ENV{SYSTEMD_WANTS}="printer.target"
-SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0701??:*", TAG+="systemd", ENV{SYSTEMD_WANTS}="printer.target"
+SUBSYSTEM=="printer", TAG+="systemd", ENV{SYSTEMD_WANTS}+="printer.target"
+SUBSYSTEM=="usb", KERNEL=="lp*", TAG+="systemd", ENV{SYSTEMD_WANTS}+="printer.target"
+SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0701??:*", TAG+="systemd", ENV{SYSTEMD_WANTS}+="printer.target"