What I have done by using debtap top convert deb package to manjaro package
1.install debtap from aur
2.update the debtap using sudo debtap -U
3.then use the debtap <deb.package> i.e debtap dcpt420wpdrv-3.5.0-1.i386.deb
4.Edit the architecture to i386 to x86_64 the .PKGINFO
5.Delete these lines in .INSTALL file
if [ “$(which semanage 2> /dev/null)” != ‘’ ];then
6.then install the created package using this command sudo paccman -U <package_name>
ignore the error and test the printer