Information processing apparatus, non-transitory computer readable medium, and information processing method

An information processing apparatus includes transmitting-receiving units, response processing units, and a switching unit. The transmitting-receiving units transmit data to and receive data from networks. An operation state of each of the response processing units is able to be switched between a first state and a second state. The switching unit performs switching between the first state and the second state of each of the response processing units. The transmitting-receiving units and the response processing units are provided for plural respective networks. In a case where all the response processing units are in the second state, the switching unit switches, among all the response processing units, an operation state of a response processing unit that has received predetermined data from the second state to the first state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2014-243461 filed Dec. 1, 2014.

BACKGROUND

Technical Field

The present invention relates to an information processing apparatus, a non-transitory computer readable medium, and an information processing method.

SUMMARY

According to an aspect of the invention, there is provided an information processing apparatus including transmitting-receiving units, response processing units, and a switching unit. The transmitting-receiving units transmit data to and receive data from networks. An operation state of each of the response processing units is able to be switched between a first state and a second state, the first state being a state in which the response processing unit does not perform response processing on data received from a corresponding transmitting-receiving unit and relegates processing of the data to a processing unit located downstream thereof, the second state being a state in which the response processing unit does not relegate processing of data received from the corresponding transmitting-receiving unit to the processing unit located downstream thereof and performs response processing on at least a portion of the data. The switching unit performs switching between the first state and the second state of each of the response processing units. The transmitting-receiving units and the response processing units are provided for plural respective networks. In a case where all the response processing units are in the second state, the switching unit switches, among all the response processing units, an operation state of a response processing unit that has received predetermined data from the second state to the first state.

DETAILED DESCRIPTION

FIG. 1is a block diagram illustrating a hardware configuration of an image forming apparatus10. As illustrated inFIG. 1, the image forming apparatus10includes a controller11, a memory12, an operation unit13, a display14, an image reading unit15, an image forming unit16, a communication unit17, an image processing unit18, and a power source controller19. In addition, various units of the image forming apparatus10are connected to a bus B1, and various types of data are transmitted and received via the bus B1.

The controller11is a unit that controls operations of the various units of the image forming apparatus10. The controller11includes a processing unit such as a central processing unit (CPU), and a storage medium (a main storage device) such as a read-only memory (ROM), a random-access memory (RAM), and the like. The CPU (a CPU110, which will be described later) reads programs stored in the ROM and the memory12, and executes the programs by using the RAM as a work area. By executing the programs in this manner, the controller11realizes forming of images on sheets, reading of an image from a document and generation of image data, performing of communication with another apparatus through communication lines, and the like.

The memory12is a unit that stores data. The memory12includes a storage medium (an auxiliary storage device) such as a hard disk, a flash memory, and the like, and stores data received by the communication unit17, data generated by the image forming apparatus10, and the like. In addition, the memory12may also include a removable storage medium (a removable medium), which is a so-called memory card, a USB memory, or the like, and a unit that reads data from and write data into the storage medium.

The operation unit13is a unit that receives an operation of a user. The operation unit13includes operators (a button, a key, and the like), and supplies a control signal corresponding to a pressed operator to the controller11. In addition, the operation unit13may also be constituted by a touch panel, which includes the display14and a sensor provided so as to overlie a display surface of the display14and supplies a control signal corresponding to a position being pressed to the controller11.

The display14is a unit that displays information. The display14includes, for example, a liquid crystal display as a display apparatus. The display14displays, under control of the controller11, a menu screen for operating the image forming apparatus10.

The image reading unit15is a unit that reads a document and converts the resulting data into image data. The image reading unit15includes an image reading device that optically reads a document and generates image data representing an image of the read document. The image reading unit15supplies the generated image data to the image processing unit18.

The image forming unit16is a unit that forms an image on a sheet. The image forming unit16includes an image forming mechanism that forms toner images of color components of YMCK on sheets using an electrophotographic system. Note that, the system used in the image forming mechanism is not limited to the electrophotographic system, and other recording systems such as an ink-jet system may also be used.

The communication unit17is a unit that transmits and receives data. The communication unit17is connected to a communication line and functions as a communication interface that performs communication with external apparatuses in a wired or wireless manner (hereinafter referred to as a “communication IF”). In an exemplary embodiment according to the invention, the communication unit17has plural physical layers (PHYs)171and plural large-scale integrated circuits (LSIs)172(seeFIG. 2), which will be described later, and functions as plural communication IFs.

The image processing unit18is a unit that performs image processing on image data. Here, the image processing is, for example, color correction and tone correction. In the case where a print function is executed in the image forming apparatus10, the image processing unit18supplies image data on which the image processing is performed to the image forming unit16.

The power source controller19is electrically connected to a power source, which is not illustrated, and controls power supply from the power source to the various units of the image forming apparatus10. The power source controller19controls power supply by reading a program stored in a storage area of the power source controller19and executing the program.

FIG. 2is a block diagram illustrating a configuration used to realize a communication function among the hardware configuration of the image forming apparatus10. As illustrated inFIG. 2, the image forming apparatus10realizes the communication function using the CPU110, the PHYs171, the LSIs172, and the power source controller19. Note that, in the configuration illustrated inFIG. 2, the PHYs171and the LSIs172are included in the communication unit17. Such a PHY171defines a physical system regarding connection to a network and data transmission in the physical later of the open systems interconnection (OSI) reference model. In the exemplary embodiment according to the invention, the communication unit17has two communication IFs (a communication IF1and a communication IF2), and has two PHYs171(a PHY171A and a PHY171B). Note that, in the exemplary embodiment, the case will be described where two communication IFs are used; however, the exemplary embodiment according to the invention is not limited to the case where two communication IFs are used. InFIG. 2, the PHY171A is provided for the communication IF1, and the PHY171B is provided for the communication IF2. The communication IF1and the communication IF2are connected to respective communication lines, which are different from each other. As a specific example, one of the communication IF1and the communication IF2is connected to the Internet, and the other one is connected to a local-area network (LAN) such as an intranet. In another example, the communication IF1and the communication IF2are connected to communication lines of respective groups (an office, a section, and the like), which are different from each other. Note that the communication IF1and the communication IF2may use either a wired system or a wireless system.

The CPU110performs communication through the communication IF1and the communication IF2. When the CPU110is in a state in which power is supplied to the CPU110or in a state in which the CPU110is fully operable (when the CPU110is on), the CPU110processes packets (each of which is an example of a data unit) output from at least one of an LSI172A and an LSI172B, which will be described later. When the CPU110is in a state in which power is not supplied to a portion or the entirety of the CPU110or in a state in which some or all of the functions of the CPU110are stopped (when the CPU110is off), the CPU110does not perform the processing. In the latter case, the state in which power is not supplied to a portion or the entirety of the CPU110is, for example, a state in which the CPU110has shifted to be in a low power state, which is set for a state in which the image forming apparatus10is not used for a predetermined time period, or the like.

Such an LSI172is a so-called network-answering proxy LSI, which processes, on behalf of the CPU110being in an off state, packets received by a communication IF. Such an LSI172is used to reduce power consumption in the CPU110. The communication unit17has two LSIs172(the LSI172A and the LSI172B) corresponding to the respective communication IFs. InFIG. 2, the LSI172A is a network-answering proxy LSI corresponding to the communication IF1and is provided between the PHY171A and the CPU110. The LSI172B is a network-answering proxy LSI corresponding to the communication IF2and is provided between the PHY171B and the CPU110. The LSIs172operate in either of operations modes: a pass-thru mode and a response standby mode. The pass-thru mode is an operation mode in which such an LSI172outputs packets received by the communication IF to the CPU110. The response standby mode is an operation mode in which such an LSI172responds through the communication IF to at least some of the packets received by the communication IF. In the following, an operation in which such an LSI172being in the response standby mode responds, on its own, to received packets is referred to as “automatic response”. While operating, such an LSI172consumes less power in the response standby mode than in the pass-thru mode.

The power source controller19controls power supply to the CPU110and the LSIs172. The power source controller19switches on-off of the CPU110, and furthermore switches the operation modes of the LSIs172.

FIG. 3is a diagram illustrating operation modes of the image forming apparatus10according to a comparative example. In this example, the image forming apparatus10communicates with an external apparatus in either of two operation modes: a normal mode and a sleep mode. Note that, inFIG. 3(andFIGS. 5, 7, and 8, which will be described later), a CPU110that is hatched indicates that the CPU110is off, and a CPU110that is not hatched indicates that the CPU110is on. In addition, an LSI172that is hatched indicates that the operation mode of the LSI172is the response standby mode, and an LSI172that is not hatched indicates that the operation mode of the LSI172is the pass-thru mode.

The normal mode is an operation mode in which the CPU110is on and the LSI172A and the LSI172B are in the pass-thru mode. In the normal mode, packets received by the communication IF1and the communication IF2are transmitted to the CPU110via the LSIs172. In this case, the CPU110performs processing corresponding to the content of the received packets. The sleep mode is an operation mode in which the CPU110is off and the LSI172A and the LSI172B are in the response standby mode. In the sleep mode, packets received by the communication IF1and the communication IF2are transmitted to the corresponding LSIs172, and the LSIs172perform processing corresponding to the content of the received packets (automatic response or packet discard). Thus, in the sleep mode, the packets received by the communication IF1and the communication IF2are processed by the LSIs172without being transmitted to the CPU110. For example, when predetermined conditions (hereinafter referred to as “power-saving conditions”) are met such as in the case where no packets are received over a predetermined time period by the communication IF1and the communication IF2, the operation mode of the image forming apparatus10is switched from the normal mode to the sleep mode. When a packet for which the CPU110needs to be on (that is, a packet that needs to be processed by the CPU110, which is hereinafter referred to as a “recovery packet”) is input to the communication IF1or the communication IF2, the operation mode of the image forming apparatus10is switched from the sleep mode to the normal mode.

For switching of the operation modes of the image forming apparatus10illustrated inFIG. 3, since on-off of the CPU110corresponds to the operation modes of all the LSIs172on a one-to-one basis, the LSI172A and the LSI172B operate in the same operation mode. However, as described above, since the LSIs172consume less power in the response standby mode than in the pass-thru mode, when the LSI172A and the LSI172B operate in the same operation mode, there may be the case where the LSIs172consume additional power. For example, even in the case where a recovery packet is received by either one of the communication IF1and the communication IF2and thus the operation mode of the image forming apparatus10is switched from the sleep mode to the normal mode, a recovery packet is not always immediately received by the other communication IF. In this case, in an LSI172corresponding to a communication IF that has not received a recovery packet, additional power is consumed by switching the operation mode of the LSI172from the response standby mode to the pass-thru mode.

FIG. 4is a block diagram illustrating a functional configuration of the image forming apparatus10. The image forming apparatus10includes transmitting-receiving units101, response processing units102, a switching unit103, and a processing unit104. The transmitting-receiving units101transmit data to and receives data from a network. The response processing units102operate in either of operation modes: a pass-thru mode and a response standby mode. When such a response processing unit102is in the pass-thru mode, the response processing unit102does not perform response processing on data received from the corresponding transmitting-receiving unit101and relegates processing of the data to the processing unit104, which is located downstream thereof. When such a response processing unit102is in the response standby mode, the response processing unit102does not relegate processing of the data received from the corresponding transmitting-receiving unit101to the processing unit104, which is located downstream thereof, and performs response processing on at least a portion of the data. The transmitting-receiving units101and the response processing units102are provided for plural respective networks. The switching unit103switches the operation mode of each of the response processing units102between the pass-thru mode and the response standby mode. In the case where all the response processing units102are in the response standby mode, the switching unit103switches, among all the response processing units102, the operation mode of a response processing unit102that has received predetermined data from the response standby mode to the pass-thru mode.

In the configuration illustrated inFIG. 2, the PHYs171are an example of the transmitting-receiving units101. The LSIs172are an example of the response processing units102. The power source controller19, which executes a program for controlling power supply, is an example of the switching unit103. The CPU110, which executes a program for controlling communication in the communication IFs, is an example of the processing unit104.

FIG. 5is a diagram illustrating the operation modes of the image forming apparatus10in the exemplary embodiment according to the invention. Note that operation states of the various units in the normal mode and in the sleep mode are similar to those forFIG. 3, and thus illustration thereof is omitted here. In the exemplary embodiment according to the invention, the image forming apparatus10realizes a power-saving mode in addition to the above-described normal mode and sleep mode. The power-saving mode is an operation mode in which the CPU110is on and either one of the LSI172A and the LSI172B is in the response standby mode (a mixture of an LSI172operating in the response standby mode and an LSI172operating in the pass-thru mode).FIG. 5illustrates a state which is an example of the power-saving mode and in which the LSI172A is in the pass-thru mode and the LSI172B is in the response standby mode. In the power-saving mode, packets received by the communication IF corresponding to an LSI172operating in the pass-thru mode are transmitted to the CPU110via the LSI172. Packets received by the communication IF corresponding to an LSI172operating in the response standby mode are processed by the LSI172without being transmitted to the CPU110.

In the exemplary embodiment according to the invention, when the image forming apparatus10is in the sleep mode, if a recovery packet is received by the communication IF1or the communication IF2, the operation mode of the image forming apparatus10is switched from the sleep mode to the power-saving mode. Here, among the LSI172A and the LSI172B, the operation mode of an LSI172corresponding to the communication IF that has received the recovery packet is switched from the response standby mode to the pass-thru mode, and the other LSI172still operates in the response standby mode. In addition, when the image forming apparatus10is in the power-saving mode, if a recovery packet is received by the communication IF corresponding to one LSI172that is in the response standby mode, the operation mode of the LSI172is switched from the response standby mode to the pass-thru mode and the operation mode of the image forming apparatus10is switched from the power-saving mode to the normal mode. Details of a process performed when the operation mode of the image forming apparatus10is switched from the sleep mode to the power-saving mode and of a process performed when the operation mode of the image forming apparatus10is switched from the power-saving mode to the normal mode will be described later.

FIG. 6is a diagram illustrating power-saving performance comparisons between the operation modes realized by the image forming apparatus10. InFIG. 6, the power-saving performance of each of the operation modes is indicated by one of three levels: “good”, “not very good”, and “not good”. “Good” indicates the highest power-saving performance among the three operation modes. “Not very good” indicates the second highest power-saving performance after “good”. “Not good” indicates the lowest power-saving performance among the three operation modes. As illustrated inFIG. 6, in the image forming apparatus10that is in the normal mode, the CPU110is on and all the LSIs172are in the pass-thru mode. Thus, the normal mode has the lowest power-saving performance among the three operation modes. In the image forming apparatus10that is in the sleep mode, the CPU110is off and all the LSIs172are in the response standby mode. Thus, the sleep mode has the highest power-saving performance among the three operation modes. In the image forming apparatus10that in the power-saving mode, the CPU110is on and there are both an LSI172operating in the pass-thru mode and an LSI172operating in the response standby mode. Thus, the power-saving mode has higher power-saving performance than the normal mode and has lower power-saving performance than the sleep mode. As described above, when the operation mode of the image forming apparatus10according to the exemplary embodiment according to the invention is switched from the sleep mode to the normal mode, the operation mode of the image forming apparatus10is switched not directly from the sleep mode to the normal mode but from the sleep mode to the power-saving mode and then to the normal mode.

FIG. 7is a diagram explaining a process performed by the image forming apparatus10when the operation mode of the image forming apparatus10is switched from the sleep mode to the power-saving mode.FIG. 7illustrates how the operation mode of the image forming apparatus10is switched from the sleep mode to the power-saving mode when a recovery packet is received by the communication IF1. As illustrated inFIG. 7, when a recovery packet is received by the communication IF1((a) inFIG. 7), the LSI172A operating in the response standby mode outputs, to the power source controller19, a signal for causing the CPU110to be on (hereinafter referred to as a “CPU on signal”) ((b) inFIG. 7). When the power source controller19receives the CPU on signal, the power source controller19switches the CPU110from off to on ((c) inFIG. 7). After switching the CPU110to on, the power source controller19outputs a signal indicating that the CPU110has been switched to on (hereinafter referred to as a “completion signal”) only to the LSI172that has output the CPU on signal (in this example, the LSI172A) ((d) inFIG. 7). When the LSI172A receives the completion signal, the operation mode of the LSI172A is switched from the response standby mode to the pass-thru mode ((e) inFIG. 7). The CPU110and the LSI172are electrically insulated (isolated) from each other when the operation mode of the image forming apparatus10is switched from the normal mode to the sleep mode. When the CPU110is switched from off to on, the CPU110cancels the isolation from the LSI172that has output the CPU on signal ((f) inFIG. 7). In accordance with a series of processes illustrated inFIG. 7, the operation mode of the only LSI172corresponding to the communication IF1that has received the recovery packet is switched from the response standby mode to the pass-thru mode, and the packets received by the LSI172are transmitted to the CPU110.

FIG. 8is a diagram explaining a process performed by the image forming apparatus10when the operation mode of the image forming apparatus10is switched from the power-saving mode to the normal mode.FIG. 8illustrates how the operation mode of the image forming apparatus10is switched from the power-saving mode to the normal mode when a recovery packet is received by the communication IF2. As illustrated inFIG. 8, when a recovery packet is received by the communication IF2((a) inFIG. 8), the LSI172B operating in the response standby mode outputs a CPU on signal to the power source controller19((b) inFIG. 8). Since the CPU110is on in the power-saving mode, when the power source controller19receives the CPU on signal, the power source controller19outputs a completion signal only to the LSI172that has output the CPU on signal (in this example, the LSI172B) ((c) inFIG. 8). When the LSI172B receives the completion signal, the operation mode of the LSI172B is switched from the response standby mode to the pass-thru mode ((d) inFIG. 8). The CPU110cancels the isolation from the LSI172that has output the CPU on signal ((e) inFIG. 8).

FIG. 9is a schematic diagram of an example of logic circuits in the power source controller19.FIG. 9illustrates logic circuits by which the power source controller19outputs a completion signal only to the LSI172that has output a CPU on signal. A signal line L11is a signal line for transferring a CPU on signal from the LSI172A to the power source controller19. A signal line L12is a signal line for transferring a CPU on signal from the LSI172B to the power source controller19. A signal line L20is a signal line for transferring a completion from the CPU110to the power source controller19. A signal line L21is a signal line for transferring a completion signal from the power source controller19to the LSI172A. A signal line L22is a signal line for transferring a completion signal from the power source controller19to the LSI172B. InFIG. 9, the power source controller19includes one OR circuit C1and two AND circuits C2(C2aand C2b). Two input terminals of the OR circuit C1are connected to the signal line L11and the signal line L12, and an output terminal of the OR circuit C1is connected to the CPU110. As a result, when a CPU on signal is output from the LSI172A or the LSI172B, the power source controller19switches the CPU110to on (inFIG. 9, the CPU on signal is output to the CPU110). One of two input terminals of the AND circuit C2ais connected to the signal line L11and the other input terminal is connected to the signal line L20. Note that upon receiving a CPU on signal from the power source controller19, the CPU110is switched to on and outputs a completion signal to the power source controller19via the signal line L20. An output terminal of the AND circuit C2ais connected to the signal line L21. As a result, only in the case where the LSI172A has output a CPU on signal, a completion signal is output to the LSI172A. One of two input terminals of the AND circuit C2bis connected to the signal line L12and the other input terminal is connected to the signal line L20. An output terminal of the AND circuit C2bis connected to the signal line L22. As a result, only in the case where the LSI172B has output a CPU on signal, a completion signal is output to the LSI172B.

FIG. 10is a flowchart illustrating a process performed by the image forming apparatus10. The process illustrated inFIG. 10is started when a packet is received by a communication IF controlled by an LSI172operating in the response standby mode. Note that, inFIG. 10, the process from step S1to step S3is executed by an LSI172corresponding to a communication IF that has received a packet among the LSI172A and the LSI172B.

In step S1, the LSI172determines whether or not the packet received by the communication IF is a recovery packet. The LSI172determines whether or not the packet is a recovery packet by, for example, analyzing the protocol and destination (an Internet Protocol (IP) address and a port number) of the packet received by the communication IF. In the case where it is determined that the received packet is not a recovery packet (NO in S1), the process proceeds to step S2. In the case where it is determined that the received packet is a recovery packet (YES in S1), the process proceeds to step S3.

In step S2, the LSI172performs automatic response to the received packet or discards the received packet. For certain packets, information on a correspondence relationship between a combination of the protocol and destination of each packet and an operation that the LSI172performs for the packet (hereinafter referred to as “correspondence information”) is prestored in a storage area of the LSI172. The LSI172performs automatic response to the packet or discards the packet in accordance with this correspondence information. After processing in step S2is performed, the process illustrated inFIG. 10ends.

In step S3, the LSI172outputs a CPU on signal to the power source controller19. In step S4, the power source controller19determines whether or not the CPU110is on. In the case where it is determined that the CPU110is off (NO in S4), the process proceeds to step S5. In the case where the image forming apparatus10is in the sleep mode, it is determined, in step S4, that the CPU110is off. In the case where it is determined that the CPU110is on (YES in S4), the process proceeds to step S6.

In step S5, the power source controller19switches the CPU110from off to on. After the power source controller19performs processing in step S5, the process proceeds to step S7.

In step S6, the power source controller19determines whether or not there is any LSI172operating in the pass-thru mode. In the case where there is an LSI172operating in the pass-thru mode (YES in S6), the process proceeds to step S7. In the case where the image forming apparatus10is in the power-saving mode, it is determined, in step S6, that there is an LSI172operating in the pass-thru mode. In the case where there is no LSI172operating in the pass-thru mode (NO in S6), the process proceeds to step S9. In the case where the operation mode of the image forming apparatus10is changing from the normal mode to the sleep mode, it is determined, in step S6, that there is no LSI172operating in the pass-thru mode.

In step S7, the power source controller19outputs a completion signal to the LSI172that has output a CPU on signal in step S3among the LSI172A and the LSI172B. A mechanism for outputting a completion signal to an LSI172that has output a CPU on signal is as illustrated inFIG. 9. Upon outputting a completion signal, the power source controller19stores an identifier that identifies the LSI172, which is the destination of the completion signal, in the storage area of the power source controller19. In the storage area of the power source controller19, an identifier is stored that identifies an LSI172to which the last completion signal is output. The operation mode of the LSI172to which a completion signal is input is switched from the response standby mode to the pass-thru mode.

In step S8, the CPU110cancels isolation from the LSI172to which a completion signal is output in step S7. Specifically, the CPU110determines the LSI172to which a completion signal is output in step S7by referring to the identifier stored in the storage area of the power source controller19, and cancels the isolation from the LSI172. Note that the CPU110may determine the LSI172to which a completion signal is output, by monitoring a completion signal traveling in the signal lines L21and L22that connect the power source controller19to the LSIs172.

In step S9, the power source controller19determines whether or not the CPU110is isolated from the LSI172. In the case where it is determined that the CPU110is isolated from the LSI172(YES in S9), the process proceeds to step S10. In the case where it is determined that the CPU110is not isolated from the LSI172(NO in S9), the process proceeds to step S11.

In step S10, the power source controller19switches the CPU110from on to off. After the power source controller19performs processing in step S10, the process proceeds to step S5. In step S11, the CPU110cancels transition of the operation mode thereof from the normal mode to the sleep mode. Specifically, the CPU110cancels the isolation from the LSI172. In step S12, the power source controller19switches, from the response standby mode to the pass-thru mode, the operation mode of the LSI172that has output a CPU on signal in step S3among the LSI172A and the LSI172B. Specifically, the power source controller19outputs a completion signal to the LSI172that has output a CPU on signal in step S3. In step S13, the CPU110performs isolation from the other LSI172, which is different from the LSI172the operation mode of which is switched to the pass-thru mode in step S12. Specifically, the CPU110determines the LSI172to which a completion signal is output in step S12by referring to the identifier stored in the storage area of the power source controller19, and performs isolation from the other LSI172, which is different from the LSI172.

As explained above, in the image forming apparatus10according to the exemplary embodiment according to the invention, the operation mode of the LSI172A and the operation mode of the LSI172B are individually switched between the pass-thru mode and the response standby mode.

The invention is not limited to the above-described exemplary embodiment, and various modifications may be made. In the following, some modifications are explained. Among the modifications explained in the following, two or more of the modifications may be combined and used.

(1) First Modification

The power source controller19may individually control plural LSIs172in terms of switching the operation mode from the pass-thru mode to the response standby mode. For example, the power source controller19determines whether or not power-saving conditions are met on a communication-IF-by-communication-IF basis, and may switch the operation mode of an LSI172corresponding to a communication IF for which the power-saving conditions are met from the pass-thru mode to the response standby mode.

(2) Second Modification

Power-saving conditions are not limited to those described in the exemplary embodiment. For example, performing of no operation on the operation unit13for over a predetermined time period and the like may also be set as power-saving conditions.

(3) Third Modification

The types and number of signals output from the LSIs172and the power source controller19are not limited to those of the signals described in the exemplary embodiment. For example, the power source controller19may also switch the operation mode of such an LSI172from the response standby mode to the pass-thru mode by outputting another signal to the LSI172in addition to a completion signal.

(4) Fourth Modification

The mechanisms with which the power source controller19outputs a completion signal only to an LSI172that has output a CPU on signal is not limited to the logic circuits illustrated inFIG. 9. For example, an identifier that identifies an LSI172that has output a CPU on signal may be prestored in the storage area of the power source controller19and the power source controller19may also output a completion signal to an LSI172uniquely identified by referring to the identifier.

The exemplary embodiment according to the invention may also be applied to information processing apparatuses other than the image forming apparatus10. For example, the exemplary embodiment according to the invention may also be applied to an image processing apparatus that performs image processing on image data and the like.

(6) Other Modifications

The configuration of the image forming apparatus10is not limited to the configuration illustrated inFIG. 1. In addition, the configuration of the communication unit17is not limited to the configuration illustrated inFIG. 3. For example, the communication unit17may also function as three or more communication IFs.

Various programs executed by the power source controller19and the CPU110in the exemplary embodiment may be stored in a computer readable storage medium such as a magnetic storage medium (a magnetic tape, a magnetic disk (a HDD, a flexible disk (FD), or the like), an optical storage medium (an optical disc (a compact disk (CD), a digital versatile disk (DVD), or the like), a magneto-optical storage medium, a semiconductor memory (a flash ROM or the like), or the like and then provided. In addition, this program may also be downloaded via a network such as the Internet.