A developing device includes a developer cartridge and a developing unit. The channel that is currently serving as the rest channel is monitored by subscriber units that are idle in the system. The burner assembly is mounted within a combustion chamber of a furnace, wherein the walls of the combustion chamber are provided with or are made up of heat transfer pipes. The interval between the first protrusions is larger than the interval between the second protrusions, so that in the case where the tray receives a shock, the semiconductor device comes into contact with the second protrusions earlier than with the first protrusions, thereby making it difficult for the resist of the semiconductor device to come off. The low side power input of the half-bridge comprises a plurality of through substrate vias that extend through the monolithic die to electrically connect a low side power pad to the monolithic die. The computer case preferably also includes a power supply support frame so that the power supply can be fixed, in a steady manner, onto the primary frame body.