Enable multilib in the pacman config by uncommenting these two lines in pacman.conf.
vim /etc/pacman.conf
[multilib]
Include = /etc/pacman.d/mirrorlist
pacman -Syu
Build package.
makepkg -si
If you can not build package because of validity check just generate correct checksums.
makepkg -g >> PKGBUILD
Add user to lp group using gpasswd.
gpasswd -a <USER> lp
Enable cups.
systemctl enable cups.service
systemctl start cups.service
If you want to use dcpj100 scanner install simple-scan brscan4 packages.
yay -S simple-scan brscan4