A printing apparatus , comprising: at least one linear guide disposed on a first surface of a back-spine section of a printer body ; and a top chassis portion (123; 802) coupled to the at least one linear guide , wherein the top chassis portion (123; 802) comprises a laser safety casing (125; 204), wherein the laser safety casing (125; 204) comprises a laser module configured to emit a laser beam along a laser path and a safety cover that is moveable to a first cover position intersecting the laser path ; and a bottom chassis portion (127; 804) fastened to the first surface of the back-spine section , wherein the at least one linear guide defines a travel path for the top chassis portion (123; 802) in a vertical axis, the travel path comprising a bottom portion in the vertical axis, and the bottom chassis portion (127; 804) is positioned under the top chassis portion (123; 802) in the vertical axis and configured to receive print media, characterized in that the printing apparatus further comprises a latch hook element connected to an outer surface of the top chassis portion (123; 802) through a bias spring , the latch hook element configured to engage a latch notch element disposed on an outer surface of the bottom chassis portion (127; 804) when the top chassis portion (123; 802) is positioned at the bottom point of the travel path, wherein the latch hook element comprises a magnetic element , and the bottom chassis portion (127; 804) comprises a magnetic switch element electronically coupled to a power supply unit , wherein the magnetic switch element is configured to detect a magnetic field strength that corresponds to a distance between the top chassis portion (123; 802) and the bottom chassis portion (127; 804) and, based on the magnetic field strength not exceeding a threshold value when the top chassis portion (123; 802) is not at the bottom point of the travel path, switch off the power supply unit . at least one linear guide disposed on a first surface of a back-spine section of a printer body ; and a top chassis portion (123; 802) coupled to the at least one linear guide , wherein the top chassis portion (123; 802) comprises a laser safety casing (125; 204), wherein the laser safety casing (125; 204) comprises a laser module configured to emit a laser beam along a laser path and a safety cover that is moveable to a first cover position intersecting the laser path ; and a bottom chassis portion (127; 804) fastened to the first surface of the back-spine section , wherein the at least one linear guide defines a travel path for the top chassis portion (123; 802) in a vertical axis, the travel path comprising a bottom portion in the vertical axis, and the bottom chassis portion (127; 804) is positioned under the top chassis portion (123; 802) in the vertical axis and configured to receive print media, characterized in that the printing apparatus further comprises a latch hook element connected to an outer surface of the top chassis portion (123; 802) through a bias spring , the latch hook element configured to engage a latch notch element disposed on an outer surface of the bottom chassis portion (127; 804) when the top chassis portion (123; 802) is positioned at the bottom point of the travel path, wherein the latch hook element comprises a magnetic element , and the bottom chassis portion (127; 804) comprises a magnetic switch element electronically coupled to a power supply unit , wherein the magnetic switch element is configured to detect a magnetic field strength that corresponds to a distance between the top chassis portion (123; 802) and the bottom chassis portion (127; 804) and, based on the magnetic field strength not exceeding a threshold value when the top chassis portion (123; 802) is not at the bottom point of the travel path, switch off the power supply unit . <EOS>