Power supplying mode switching controller, image forming apparatus, and image reading apparatus

An image forming apparatus which forms an image on a recording medium by using a plotter and/or a scanner, comprising:

• a main power source which supplies an operating voltage to all elements in the image forming apparatus;
• a main controller which controls the image forming apparatus;
• a sub power supply circuit which has a normal mode for supplying the operating voltage to all the elements of the image forming apparatus and a power saving mode for cutting off the operating voltage to a part of the image forming apparatus;
• an I/O controller which causes the sub power supply circuit to switch to the normal mode when a factor for returning to the normal mode is generated in the power saving mode of the sub power supply circuit;
• a detachable recording medium interface to which a detachable recording medium is attached in the I/O controller;
• and
• a communication device interface configured to make operations of a communication device, to which interface the communication device is attached in the I/O controller, wait, wherein
• the I/O controller includes a first attaching change detecting circuit which detects an attaching change of the detachable recording medium to the detachable recording medium interface;
• when the first attaching change detecting circuit detects the attaching change of the detachable recording medium to the detachable recording medium interface in the power saving mode, the I/O controller causes the sub power supply circuit to switch to the normal mode and informs the main controller of the attaching change of the detachable recording medium, and the main controller renews information in a memory to be attaching change information;
• the I/O controller includes a second attaching change detecting circuit which detects an attaching change of the communication device to the communication device interface;
• and
• when the second attaching change detecting circuit detects the attaching change of the communication device to the communication interface in the power saving mode, the I/O controller causes the sub power supply circuit to switch to the normal mode and informs the main controller of the attaching change of the communication device, and the main controller renews information in the memory to be attaching change information.

A power supplying mode switching method, comprising:

• controlling, by a main controller, an image forming apparatus;
• switching, by an I/O controller, a sub power supply circuit to a normal mode for supplying an operating voltage to the image forming apparatus including the main controller, when a factor for returning to the normal mode is generated while the sub power supply circuit is in a power saving mode for cutting off the operating voltage to a part of the image forming apparatus including the main controller;
• detecting an attachment change of a detachable recording medium to the I/O controller;
• and
• when an attachment change is detected in the detecting step while the sub power supply circuit is in the power saving mode, switching, by the I/O controller, the sub power supply circuit to the normal mode, informing the main controller of the attachment change of the detachable recording medium, and renewing, by the main controller, attachment change information in a memory.