Image Forming Apparatus Method and Storage Medium Storing Program for Controlling Display When the Image Forming Appratus Returns to an Active State from a Power-Saving State

1. An image forming apparatus comprising: a detection unit configured to detect a cause for causing the image forming apparatus to return to an active state from a power-saving state, wherein power is supplied to the detection unit in both the active state and the power-saving state; an attachment unit configured to allow an external memory device to be attached to the image forming apparatus, wherein no power is supplied to the attachment unit in the power-saving state; a return unit configured to cause, when the detection unit detects the cause, the image forming apparatus to return to the active state from the power-saving state; a first determination unit configured to determine, when the return unit causes the image forming apparatus to return to the active state from the power-saving state, whether or not the detection unit detects a predetermined cause; a second determination unit configured to determine, when the return unit causes the image forming apparatus to return to the active state from the power-saving state, whether or not the external memory device is attached to the attachment unit; and a control unit configured to control, when (a) the first determination unit determines that the detection unit detects the predetermined cause and (b) the second determination unit determines that the external memory device is attached to the attachment unit, a display unit (i) not to display a default screen for displaying a plurality of functions selectable by a user and (ii) to display a first screen for performing a function, of the plurality of functions, using the external memory device.

2. The image forming apparatus according to claim 1 , wherein the control unit is further configured to control, when (a) the first determination unit determines that the detection unit does not detect the predetermined cause and (b) the second determination unit determines that the external memory device is attached to the attachment unit, the display unit (i) not to display the default screen and (ii) to display a second screen for performing the function using the external memory device.

3. The image forming apparatus according to claim 2 , wherein the first screen and the second screen are different from each other.

4. The image forming apparatus according to claim 3 , wherein, when the predetermined cause is that an original document is placed on a reading unit configured to read the original document to generate image data of the original document, the first screen is a screen for storing image data read by the reading unit into the external memory device and the second screen is a screen for printing image data stored in the external memory device.

5. The image forming apparatus according to claim 1 , wherein the control unit is further configured to control, when (a) the first determination unit determines that the detection unit detects the predetermined cause and (b) the second determination unit determines that the external memory device is not attached to the attachment unit, the display unit to display the default screen.

6. The image forming apparatus according to claim 1 , wherein the control unit is further configured to control, when (a) the first determination unit determines that the detection unit does not detect the predetermined cause and (b) the second determination unit determines that the external memory device is not attached to the attachment unit, the display unit to display the default screen.

7. The image forming apparatus according to claim 1 , wherein the predetermined cause is that an original document is placed on a reading unit configured to read the original document to generate image date of the original document.

8. A method for controlling an image forming apparatus including (a) a detection unit configured to detect a cause for causing the image forming apparatus to return to an active state from a power-saving state, wherein power is supplied to the detection unit in both the active state and the power-saving state, and (b) an attachment unit configured to allow an external memory device to be attached to the image forming apparatus, wherein no power is supplied to the attachment unit in the power-saving state, the method comprising: a return step of causing, when the detection unit detects the cause, the image forming apparatus to return to the active state from the power-saving state; a first determination step of determining, when the image forming apparatus is caused in the return step to return to the active state from the power-saving state, whether or not the detection unit detects a predetermined cause; a second determination step of determining, when the image forming apparatus is caused in the return step to return to the active state from the power-saving state, whether or not the external memory device is attached to the attachment unit; a control step of controlling, when (a) it is determined in the first determination step that the detection unit detects the predetermined cause and (b) it is determined in the second determination step that the external memory device is attached to the attachment unit, a display unit (i) not to display a default screen for displaying a plurality of functions selectable by a user and (ii) to display a first screen for performing a function, of the plurality of functions, using the external memory device.

9. A non-transitory computer-readable storage medium storing a program for causing a computer to execute each of the steps of a method for controlling an image forming apparatus including (a) a detection unit configured to detect a cause for causing the image forming apparatus to return to an active state from a power-saving state, wherein power is supplied to the detection unit in both the active state and the power-saving state, and (b) an attachment unit configured to allow an external memory device to be attached to the image forming apparatus, wherein no power is supplied to the attachment unit in the power-saving state, the method comprising: a return step of causing, when the detection unit detects the cause, the image forming apparatus to return to the active state from the power-saving state; a first determination step of determining, when the image forming apparatus is caused in the return step to return to the active state from the power-saving state, whether or not the detection unit detects a predetermined cause; a second determination step of determining, when the image forming apparatus is caused in the return step to return to the active state from the power-saving state, whether or not the external memory device is attached to the attachment unit; a control step of controlling, when (a) it is determined in the first determination step that the detection unit detects the predetermined cause and (b) it is determined in the second determination step that the external memory device is attached to the attachment unit, a display unit (i) not to display a default screen for displaying a plurality of functions selectable by a user and (ii) to display a first screen for performing a function, of the plurality of functions, using the external memory device.