An apparatus includes a control unit that switches a power state between first and second power states, the first power state being a state where one of a plurality of cores is usable and the other cores are unusable, the second power state being a state where the plurality of cores is unusable. Based on reception of the predetermined signal in a case where the apparatus is in the second power state, the control unit causes the apparatus to transition from the second power state to the first power state, and under a first condition to be met after the transition to the first power state in a case where the apparatus is in the first power state, the control unit causes the apparatus to transition from the first power state to the second power state.

An image forming apparatus capable of switching power state between a first power state and a second power state, which is lower in power than the first power state, shifts from the second power state to the first power state. In a case where the image forming apparatus shifts to the second power state in response to a current time reaching a set time, the image forming apparatus is controlled not to shift from the second power state to the first power state in response to an object approaching the image forming apparatus being detected.

An image reading apparatus includes a reading controller, a data generating circuit unit, a document holder, an opening/closing sensor which provides an output of a first level when the document holder is open by an angle equal to or more than a predetermined angle, and a storage unit which stores an adjustment value. Where a return is made from a power saving mode to an active mode, when an output level of the opening/closing sensor is the first level, the reading controller makes a setting for an operation of the data generating circuit unit based on the adjustment value stored in the storage unit, and then makes the reading unit perform reading for document size detection.

An image forming apparatus communicates with another device and includes a processor that controls the communication. A control unit controls the apparatus to operate in one of at least a first power saving state, a second power saving state, and a normal state. In the first power saving state, the apparatus is controlled so that an image forming unit, an image reading unit, and the control unit are not activated, and a communication device is activated. In the second power saving state, the apparatus is controlled so that at least one of the image forming unit and the image reading unit are not activated, and the communication device and the control unit are activated. In the normal state, the apparatus is controlled so that at least the image forming unit, the image reading unit, the communication device, and the control unit are activated.

An example image forming apparatus includes a communication device including a physical layer protocol chip for performing communication with a network by using a connector with a light emitting element for displaying a network connection state and a physical layer protocol, a print engine to perform a print job, and a processor to, based on print data being received through the communication device, control the print engine to print the received print data, determine whether a network cable is connected to the connector based on an operation state of the light emitting element, and, based on a determination that the network cable is not connected to the connector, control the physical layer protocol chip to be in a power-saving state.

When a home position sensor detects that an operation unit has been moved out of a home position, a function of a human detection sensor is temporarily disabled. This makes it possible to prevent the human detection sensor from wastefully continuing the detection operation although the human detection sensor is unable to detect a person intending to use an image forming apparatus, and from erroneously detecting a person not intending to use the image forming apparatus.

In a case where an image forming apparatus has entered into a sleep mode, a user is required to wait, after issuing an instruction for image formation via a wireless operation unit, until the image forming apparatus returns from the sleep mode to a standby mode, for the requested processing to be performed. Accordingly, an image forming system is provided that includes an image forming apparatus capable of transitioning between a standby mode and a sleep mode includes a wireless operation unit capable of performing wireless communication with the image forming apparatus, and that includes a counter for counting a time for determining timing of transition from the standby mode to the sleep mode, and a resetter capable of resetting a count value of the counter in response to a predetermined icon being selected in the wireless operation unit in the standby mode.

An image forming system comprising: an image forming apparatus capable of transitioning between a standby mode and a sleep mode; and a wireless operation device capable of wireless communication with the image forming apparatus, the wireless operation device including: a display; a battery configured to perform power supply to the display; and a controller configured to control the power supply from the battery to the display, wherein, in response to transition of the image forming apparatus from the standby mode to the sleep mode with a predetermined amount of power being supplied from the battery to the display, the controller makes a supply amount of power from the battery to the display less than the predetermined amount.

A communication I/F of an image generating unit writes settings for an image data to a transitory storage unit by serial communication before the image data is transmitted from the image generating unit to the transitory storage unit. The communication I/F stores partial information of an address used for previous writing in a cache unit, and omits the writing of the partial information of the address used for further writing if the partial information of the address matches the partial information of the stored address.

An image reading apparatus includes a first posture detection unit that detects a first posture that is a posture of the apparatus main body when not in use, a second posture detection unit that detects a second posture that is a posture of the apparatus main body when in use, and a posture change detection unit that detects a change in a posture of the apparatus main body. When the first posture detection unit detects a switchover of the apparatus main body to the first posture in a first power supply mode in which power is supplied to the first posture detection unit, the second posture detection unit, and the posture change detection unit, the first power supply mode transitions to the second power supply mode in which a controller supplies power to only the posture change detection unit.