1. An image processing apparatus, comprising: a switch section to be operated to start supply of an external voltage; a power supply section using the external voltage to generate a power supply voltage and supply the generated power supply voltage; an operation display section using the power supply voltage to perform an operation; an image processing section using the power supply voltage to perform a specific image processing; and a main body controller using the power supply voltage to perform an operation and including a first CPU, a first non-volatile memory, and a first RAM, wherein the main body controller being configured to operate as: an initialization control part for outputting screen data to the operation display section, the screen data representing operation screens for allowing an execution condition for use in the image processing to be inputted and causing the operation display section to start a predetermined first initialization processing when the power supply section starts to supply the power supply voltage in response to the operation of the switch section by a user, and causing the image processing section to start a predetermined second initialization processing after the start of the first initialization processing; and a condition receiving part for accepting an input of the execution condition after completion of the second initialization processing, the operation display section includes: a display part; and an operation controller including a second CPU, a second non-volatile memory, and a second RAM, the operation controller using a part of a storage region of the second RAM as a storage part, and the operation controller further being configured to operate as: a display control part for storing the screen data obtained from the initialization control part in the storage part during the first initialization processing, obtaining the screen data from the storage part after completion of the first initialization processing, and causing the display part to display the operation screen represented by the obtained screen data; and a condition setting part for, when the execution condition is inputted via the operation screen during the second initialization processing, storing the execution condition in the storage part and, in a case where the execution condition is stored in the storage part after completion of the second initialization processing, outputting the execution condition stored in the storage part to the condition receiving part and subsequently deleting the execution condition stored in the storage part, thereafter, when the execution condition is inputted via the operation screen, outputting the inputted execution condition to the condition receiving part without storing the inputted execution condition in the storage part.