Information processing apparatus, communication control method and communication system

An information processing apparatus has a release mode and a power saving mode with less power consumption, the information processing apparatus comprises: a communication part that communicates with a first information processing apparatus and a terminal apparatus; a storage part that stores first information which is information to be included in a response with respect to a command transmitted from the terminal apparatus by multicasting and received by the communication part; and a control part that sets a response function with respect to the command to either “valid” or “invalid” during the power saving mode. Wherein the control part transmits via the communication part the first information to the first information processing apparatus that performs a proxy response with respect to the command, and thereafter, sets the response function to “invalid” and executes a process to transit from the release mode to the power saving mode.

TECHNICAL FIELD

The present invention relates to an information processing apparatus, a communication control method, and a communication system.

There is a system in which a plurality of apparatuses communicate with each other via a network. In this system, an apparatus that receives an inquiry from another apparatus responds to the inquiry (see Patent Document 1). For example, a printing apparatus of Patent Document 1 has a setting switch. When the setting switch is in an ON state, the printing apparatus responds to an inquiry transmitted by broadcasting (may be referred as multicasting) by a host apparatus.

RELATED ART

On the other hand, in order to suppress power consumption, an apparatus having a power saving mode is known. In order to acquire information (for example, apparatus information) stored in the apparatus, a transmission instruction of the information may be transmitted by multicasting. When a transmission instruction is received in a state of the power saving mode, in order to respond to the transmission instruction, the apparatus releases the power saving mode, and transitions to a standby mode or the like, and responds. In the future, it is required to reduce the number of times when the power saving mode is released.

The present invention is intended to reduce the number of times when the power saving mode is released.

SUMMARY

An information processing apparatus, disclosed in the application, that performs in either one of two different power modes that are a power saving mode and a release mode, the release mode being a state to which the power saving mode turns by being released and in which power consumption of the information processing apparatus is higher than that in the power saving mode, the information processing apparatus comprises: a communication part that communicates with a first information processing apparatus, which is different from the information processing apparatus, and a terminal apparatus; a storage part that stores first information which is information to be included in a response with respect to a command transmitted from the terminal apparatus by multicasting and received by the communication part; and a control part that sets a response function with respect to the command to either “valid” or “invalid” during the power saving mode. Wherein the control part transmits via the communication part the first information to the first information processing apparatus that performs a proxy response with respect to the command, and thereafter, sets the response function to “invalid” and executes a process to transit from the release mode to the power saving mode.

According to the present invention, the number of times when the power saving mode is released can be reduced.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

In the following, an embodiment is described with reference to the drawings. The following embodiment is merely an example, and various modifications are possible within the scope of the present invention.

Embodiment

FIG. 1illustrates a communication system. The communication system includes image forming apparatuses100,200,300. Further, the communication system may also include a terminal apparatus400. The image forming apparatuses100,200,300and the terminal apparatus400are connected to each other via a network10. For example, the network10is a LAN (Local Area Network) or a WAN (Wide Area Network).

The image forming apparatuses100,200,300are each, for example, a printer, a copying machine, a facsimile machine, a multifunction machine, or the like. The image forming apparatuses100,200,300are each an apparatus that executes a communication control method. The image forming apparatuses100,200,300are also each referred to as an information processing apparatus. An information processing apparatus may be an apparatus that does not have an image forming function. An information processing apparatus may be a computer. The image forming apparatus100, the image forming apparatus200, or the image forming apparatus300may be referred to as a first information processing apparatus or a second information processing apparatus.

The image forming apparatuses100,200,300are each in a release mode or a power saving mode. The release mode is a state in which the power saving mode is released, and is a state in which power consumption is higher than that in the power saving mode. For example, the release mode is a standby mode, an operation mode, or the like. The operation mode is a state in which a normal operation can be performed. The release mode may also be expressed as an operating state which is an operable state.

The power saving mode is a state in which power consumption is lower than that in the release mode. Further, the power saving mode is a state in which an operation is restricted by lowering power consumption. The terminal apparatus400is an apparatus that is used by a user. The terminal apparatus400transmits a command to the image forming apparatuses100,200,300by multicasting. For example, a command is a transmission instruction. For example, a transmission instruction is to instruct transmission of apparatus information stored by the image forming apparatuses100,200,300. For example, the apparatus information includes apparatus names and IP (Internet Protocol) addresses of the image forming apparatuses100,200,300.

In the following description, it is assumed that the terminal apparatus400transmits a transmission instruction to the image formation apparatuses100,200,300by multicasting. Further, whether or not the image forming apparatuses100,200,300respond to the transmission instruction will be described in detail later. With a conventional structure, the terminal apparatus is able to send another transmission instruction that is designated to a single image forming apparatus. The another transmission instruction may be referred as an individual transmission instruction, and such an instruction may be referred as to be transmitted by unicasting.

Next, a part of hardware of each of the image forming apparatuses100,200,300and the terminal apparatus400is described.FIG. 2illustrates a part of the hardware of the image forming apparatus100. The image forming apparatus100has a processor101, a volatile storage device102, and a nonvolatile storage device103.

The processor101controls the entire image forming apparatus100. For example, the processor101is a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or the like. The processor101may be a multi-processor. The image forming apparatus100may be realized by a processing circuit, or may be realized by software, firmware or a combination thereof

The volatile storage device102is a main storage device of the image forming apparatus100. For example, the volatile storage device102is a RAM (Random Access Memory). The nonvolatile storage device103is an auxiliary storage device of the image forming apparatus100. For example, the nonvolatile storage device103is an SSD (Solid State Drive) or the like.

Similar to the image forming apparatus100, the image forming apparatuses200,300and the terminal apparatus400each have a processor, a volatile storage device, and a nonvolatile storage device. Here, a name of the image forming apparatus100is an image forming apparatus A. A name of the image forming apparatus200is an image forming apparatus B. A name of the image forming apparatus300is an image forming apparatus C.

FIG. 3is a functional block diagram illustrating a configuration of the image forming apparatus A. The image forming apparatus100has a control part110, an image forming part120, a carrying part130, a storage part140, an operation display part150, a communication part160, and a power saving handling part170. It is also possible that the control part110, the operation display part150, the communication part160(Comm. Part inFIG. 3), and the power saving handling part170are each partially or entirely realized by the processor101. It is also possible that the control part110, the operation display part150, the communication part160, and the power saving handling part170are each partially or entirely realized as a module of a communication control program executed by the processor101. The program is stored in the volatile storage device102or the nonvolatile storage device103.

The storage part140is realized as a storage area secured in the volatile storage device102or the nonvolatile storage device103. The control part110controls the entire image forming apparatus100. Functions of the control part110will be described in detail later.

The image forming part120forms an image on a print medium based on print data. The carrying part130carries a print medium accommodated in a medium accommodating part (not illustrated in the drawings) to the image forming part120and ejects the print medium on which an image is formed to outside of the image forming apparatus100. The storage part140stores various pieces of information. The various pieces of information will be described in detail later. The operation display part150provides various pieces of information to an operator using the image forming apparatus100. For example, the operation display part150displays information about an operation of the image forming apparatus100on a display.

The communication part160communicates with the image forming apparatuses200,300and the terminal apparatus400via the network10. The power saving handling part170receives power supply from a battery or the like when the image forming apparatus100is in the power saving mode. Further, the storage part140and the communication part160receive power supply from a battery or the like when the image forming apparatus100is in the power saving mode. The control part110, the image forming part120, the carrying part130, and the operation display part150do not receive power from a battery or the like when the image forming apparatus100is in the power saving mode. That is, power supplied to the control part110, the image forming part120, the carrying part130, and the operation display part150is stopped. As a result, the image forming apparatus100can suppress power consumption.

In this embodiment, the power saving mode means either that one of control part110and operation display part150does not receive a power supply or that none of these parts (110and150) does not receive a power supply. Compared with the release mode, the image forming apparatus may use only 20% power. In the light of the present invention, the power saving mode may consume a power that is ranged from 10 to 25% related to that of the release mode. Putting it simply, the power saving mode can be defined as a mode under which the image forming apparatus consumes 50% or less power than the release mode.

The power saving handling part170does not receive power supply when the image forming apparatus100is in the release mode. The control part110, the image forming part120, the carrying part130, the storage part140, the operation display part150, and the communication part160receive power supply when the image forming apparatus100is in the release mode. Functions of the power saving handling part170will be described in detail later.

FIG. 4is a functional block diagram illustrating a configuration of the image forming apparatus B. The image forming apparatus200has a control part210, an image forming part220, a carrying part230, a storage part240, an operation display part250, a communication part260, and a power saving handling part270.

It is also possible that the control part210, the operation display part250, the communication part260, and the power saving handling part270are each partially or entirely realized by a processor of the image forming apparatus200. It is also possible that the control part210, the operation display part250, the communication part260, and the power saving handling part270are each partially or entirely realized as a module of a communication control program executed by the processor of the image forming apparatus200. The program is stored in a volatile storage device or a nonvolatile storage device of the image forming apparatus200. The storage part240is realized as a storage area secured in the volatile storage device or the nonvolatile storage device of the image forming apparatus200.

Functions of the control part210, the image forming part220, the carrying part230, the operation display part250, the communication part260, and the power saving handling part270are respectively the same as the functions of the control part110, the image forming part120, the carrying part130, the operation display part150, communication part160, and the power saving handling part170, and thus, descriptions thereof are omitted. Further, power supply destinations in the power saving mode and the release mode are the same between the image forming apparatus100and the image forming apparatus200.

FIG. 5is a functional block diagram illustrating a configuration of the image forming apparatus C. The image forming apparatus300has a control part310, an image forming part320, a carrying part330, a storage part340, an operation display part350, a communication part360, and a power saving handling part370.

It is also possible that the control part310, the operation display part350, the communication part360, and the power saving handling part370are each partially or entirely realized by a processor of the image forming apparatus300. It is also possible that the control part310, the operation display part350, the communication part360, and the power saving handling part370are each partially or entirely realized as a module of a communication control program executed by the processor of the image forming apparatus300. The program is stored in a volatile storage device or a nonvolatile storage device of the image forming apparatus300. The storage part340is realized as a storage area secured in the volatile storage device or the nonvolatile storage device of the image forming apparatus300.

Functions of the control part310, the image forming part320, the carrying part330, the operation display part350, the communication part360, and the power saving handling part370are respectively the same as the functions of the control part110, the image forming part120, the carrying part130, the operation display part150, communication part160, and the power saving handling part170, and thus, descriptions thereof are omitted. Further, the power supply destinations in the power saving mode and the release mode are the same between the image forming apparatus100and the image forming apparatus300.

FIG. 6is a functional block diagram illustrating a configuration of the terminal apparatus. The terminal apparatus400has a control part410, a storage part420, an operation display part430, and a communication part440. The control part410controls the entire terminal apparatus400. The storage part420stores information used for processing executed by the control part410. The operation display part430displays on a display of the terminal apparatus400various pieces of information to a user using the terminal apparatus400. The communication part440communicates with the image forming apparatuses100,200,300via the network10.

FIG. 7illustrates an example of a control table. A control table141is also referred to as control information. The control table141is stored in the storage part140. Further, the storage part240and the storage part340each similarly store a control table.

“Valid” or “invalid” is set in the control table141. “Valid” indicates to respond to a command transmitted by multicasting. “Invalid” indicates not to respond to a command transmitted by multicasting. Therefore, when “valid” is set in the control table141, the image forming apparatus100responds to a command transmitted by multicasting. Further, when “invalid” is set in the control table141, the image forming apparatus100does not respond to a command transmitted by multicasting.

Here, in the power saving mode, the control part110sets a response function with respect to a transmission instruction transmitted by the terminal apparatus400to “valid” or “invalid.” This is described in detail below. In the power saving mode, in a case of responding to a transmission instruction transmitted by the terminal apparatus400, the control part110sets “valid” in the control table141. In the power saving mode, in a case of not responding to a transmission instruction transmitted by the terminal apparatus400, the control part110sets “invalid” in the control table141.

FIG. 8illustrates a specific example of the storage part of the image forming apparatus A. The storage part140stores response information. The response information is information to be included in a response with respect to a transmission instruction received by the communication part160and transmitted by multicasting by the terminal apparatus400. Further, the response information may also be expressed as information required for a response to a transmission instruction transmitted by the terminal apparatus400. Further, the response information may also be expressed as multicasting response information.

The response information includes an apparatus name and an IP address. That is, the response information is apparatus information. For example, the apparatus name included in the response information is an apparatus name of the image forming apparatus100. The IP address is an IP address “192.168.100.1” assigned to the image forming apparatus100. The response information may include information other than the apparatus name and the IP address. In the following, the response information including the apparatus name of the image forming apparatus100and the IP address assigned to the image forming apparatus100is referred to as response information A1. Here, the apparatus information or response information specifying its own information processing apparatus is referred to as first information. The storage part140may also store response information of other apparatuses.

FIG. 9illustrates a specific example of the storage part of the image forming apparatus B. The storage part240stores response information. The response information includes an apparatus name and an IP address. For example, the apparatus name is an apparatus name of the image forming apparatus200. The IP address is an IP address “192.168.100.2” assigned to the image forming apparatus200. The response information may include information other than the apparatus name and the IP address. In the following, the response information including the apparatus name of the image forming apparatus200and the IP address assigned to the image forming apparatus200is referred to as response information B1.

The storage part240can also store response information of other apparatuses.FIG. 9illustrates a state in which the response information A1is stored in the storage part240. In what situation the response information A1is stored in the storage part240will be described in detail later.

FIG. 10illustrates a specific example of the storage part of the image forming apparatus C. The storage part340stores response information. The response information includes an apparatus name and an IP address. For example, the apparatus name is an apparatus name of the image forming apparatus300. The IP address is an IP address “192.168.100.3” assigned to the image forming apparatus300. The response information may include information other than the apparatus name and the IP address. In the following, the response information including the apparatus name of the image forming apparatus300and the IP address assigned to the image forming apparatus300is referred to as response information C1.

The storage part340can also store response information of other apparatuses.FIG. 10illustrates a state in which the response information A1and the response information B1are stored in the storage part340. In what situation the response information A1and the response information B1are stored in the storage part340will be described in detail later.

Next, communication processes performed between the image forming apparatuses100,200,300, and the terminal apparatus400are described using sequence diagrams.FIG. 11is a part1of a sequence diagram illustrating an example of a transition process to the power saving mode. In the description ofFIGS. 11-14,FIGS. 1, 3-5 and 7-10are referenced. Further, it is assumed that the image forming apparatuses100,200,300are in the release mode. Further, it is assumed that “valid” is set in the control tables of the image forming apparatuses100,200,300.

(Step S101) The control part110of the image forming apparatus100performs transition preparation in order to transition to the power saving mode.

(Step S102) The control part110of the image forming apparatus100transmits via the communication part160a response instruction by multicasting. The response instruction instructs a response. A multicast address is set for a destination address included in the response instruction. For example, the multicast address is a multicast address previously set as a destination address included in a command transmitted by multicasting by the terminal apparatus400. In this way, the communication part160transmits the response instruction to the image forming apparatuses200,300belonging to a multicast group.

(Step S103) The control part210of the image forming apparatus200refers to the control table stored in the storage part240and detects that “valid” is set. The communication part260of the image forming apparatus200transmits a response with respect to the response instruction to the image forming apparatus100. The IP address “192.168.100.2” is included in the response.

(Step S104) The control part310of the image forming apparatus300refers to the control table stored in the storage part340and detects that “valid” is set. The communication part360of the image forming apparatus300transmits a response with respect to the response instruction to the image forming apparatus100. The IP address “192.168.100.3” is included in the response.

(Step S105) The control part110of the image forming apparatus100selects a representative image forming apparatus from the image forming apparatuses that responded with respect to the response instruction. InFIG. 11, it is assumed that the control part110of the image forming apparatus100has selected the image forming apparatus200. That is because the image forming apparatus200made a response earlier than others. Here, the representative image forming apparatus is also referred to as a first information processing apparatus. Further, the representative image forming apparatus is an apparatus that performs a proxy response with respect to a transmission instruction transmitted by the terminal apparatus400.

(Step S106) The control part110of the image forming apparatus100transmits via the communication part160the response information A1stored in the storage part140to the image forming apparatus200. That is, the control part110of the image forming apparatus100transmits via the communication part160the response information A1to the image forming apparatus200that performs a proxy response with respect to a transmission instruction transmitted by the terminal apparatus400. As a result, the response information A1is stored in the storage part240of the image forming apparatus200.FIG. 9illustrates a state in which the response information A1is stored in the storage part240.

(Step S107) The control part110of the image forming apparatus100sets the response function to “invalid.” That is, the control part110of the image forming apparatus100sets “invalid” in the control table141. As a result, the image forming apparatus100stops responding to a command transmitted by multicasting.

(Step S108) The control part110of the image forming apparatus100executes a process to transition from the release mode to the power saving mode. For example, the control part110instructs a power supply circuit (not illustrated in the drawings) of the image forming apparatus100to change the power supply destination to the storage part140, the communication part160and the power saving handling part170. As a result, power is not supplied to the control part110and the like. Then, the image formation apparatus100transitions to the power saving mode.

FIG. 12is a part2of the sequence diagram illustrating the example of the transition process to the power saving mode.

(Step S111) The control part210of the image forming apparatus200performs transition preparation in order to transition to the power saving mode.

(Step S112) The control part210of the image forming apparatus200transmits via the communication part260a response instruction by multicasting. A multicast address is set for a destination address included in the response instruction. For example, the multicast address is a multicast address previously set as a destination address included in information transmitted by multicasting by the terminal apparatus400.

(Step S113) The control part310of the image forming apparatus300refers to the control table stored in the storage part340and detects that “valid” is set. The communication part360of the image forming apparatus300transmits a response with respect to the response instruction. The IP address “192.168.100.3” is included in the response.

(Step S114) The power saving handling part170of the image forming apparatus100receives the response instruction via the communication part160. The power saving handling part170of the image forming apparatus100refers to the control table141and detects that “invalid” is set. Therefore, the power saving handling part170of the image forming apparatus100does not respond to the response instruction. Further, the power saving handling part170of the image forming apparatus100does not release the power saving mode. In this way, when the image forming apparatus100is in the power saving mode and “invalid” is set in the control table141, the image forming apparatus100does not release the power saving mode. Further, the power saving handling part170of the image forming apparatus100may discard the response instruction (that is, the command).

(Step S115) The control part210of the image forming apparatus200selects a representative image forming apparatus from the image forming apparatuses that responded with respect to the response instruction. That is, the control part210of the image forming apparatus200selects the image forming apparatus300. As described above, the image forming apparatus300selected as the representative image forming apparatus is also referred to as a first information processing apparatus.

(Step S116) The control part210of the image forming apparatus200transmits via the communication part260the response information A1and the response information B1to the image forming apparatus300. That is, the control part210of the image forming apparatus200transmits the response information A1and the response information B1to the image forming apparatus300that performs a proxy response with respect to a transmission instruction transmitted by the terminal apparatus400. As a result, the response information A1and the response information B1are stored in the storage part340of the image forming apparatus300.FIG. 10illustrates a state in which the response information A1and the response information B1are stored in the storage part340.

(Step S117) The control part210of the image forming apparatus200sets the response function to “invalid.” That is, the control part210of the image forming apparatus200sets “invalid” in the control table stored in the storage part240. As a result, the image forming apparatus200stops responding to a command transmitted by multicasting.

(Step S118) The control part210of the image forming apparatus200executes a process to transition to the power saving mode. As a result, the image formation apparatus200transitions to the power saving mode.

FIG. 13is a part3of the sequence diagram illustrating the example of the transition process to the power saving mode.

(Step S121) The control part310of the image forming apparatus300performs transition preparation in order to transition to the power saving mode.

(Step S122) The control part310of the image forming apparatus300transmits via the communication part360a response instruction by multicasting. A multicast address is set for a destination address included in the response instruction. For example, the multicast address is a multicast address previously set as a destination address included in information transmitted by multicasting by the terminal apparatus400.

(Step S123) The power saving handling part170of the image forming apparatus100refers to the control table141and detects that “invalid” is set. Therefore, the power saving handling part170of the image forming apparatus100does not respond to the response instruction. Further, the power saving handling part170of the image forming apparatus100does not release the power saving mode.

(Step S124) The power saving handling part270of the image forming apparatus200refers to the control table stored in the storage part240and detects that “invalid” is set. Therefore, the power saving handling part270of the image forming apparatus200does not respond to the response instruction. Further, the power saving handling part270of the image forming apparatus200does not release the power saving mode. In this way, when the image forming apparatus200is in the power saving mode and “invalid” is set in the control table stored in the storage part240, the image forming apparatus200does not release the power saving mode.

(Step S125) The control part310of the image forming apparatus300maintains “valid” set in the control table stored in the storage part340.

(Step S126) The control part310of the image forming apparatus300executes a process to transition to the power saving mode. As a result, the image formation apparatus300transitions to the power saving mode. In this way, when there is no response with respect to the response instruction, the control part310executes a process to transition from the release mode to the power saving mode while the response function remains being set to “valid.”

Considering working circumstances, the control part310varies the waiting period to determine that there is no response. It may be 1 second or 5 minutes or more. In the embodiment, the period is 20 seconds. It may be practical for the waiting period to be ranged between 5 seconds and 60 seconds, and preferably between 10 seconds to 30 seconds.

FIG. 14is a part4of the sequence diagram illustrating the example of the transition process to the power saving mode.

(Step S131) The terminal apparatus400transmits a transmission instruction to the image forming apparatuses100,200,300by multicasting. A multicast address is set for a destination address included in the transmission instruction.

(Step S132) The power saving handling part170of the image forming apparatus100refers to the control table141and detects that “invalid” is set. Therefore, the power saving handling part170of the image forming apparatus100does not respond to the transmission instruction. Further, the power saving handling part170of the image forming apparatus100does not release the power saving mode. Further, the power saving handling part170of the image forming apparatus100may discard the transmission instruction (that is, the command).

(Step S133) The power saving handling part270of the image forming apparatus200refers to the control table stored in the storage part240and detects that “invalid” is set. Therefore, the power saving handling part270of the image forming apparatus200does not respond to the transmission instruction. Further, the power saving handling part270of the image forming apparatus200does not release the power saving mode. Further, the power saving handling part270of the image forming apparatus200may discard the transmission instruction.

(Step S134) The power saving handling part370of the image forming apparatus300refers to the control table stored in the storage part340and detects that “valid” is set. Therefore, the power saving handling part370of the image forming apparatus300responds to the transmission instruction. The power saving handling part370of the image forming apparatus300executes a process to release the power saving mode. For example, the power saving handling part370instructs a power supply circuit (not illustrated in the drawings) of the image forming apparatus300to change the power supply destination to the control part310or the like. As a result, power is supplied to the control part310and the like. Then, the image formation apparatus300transitions to the release mode. In this way, when the image forming apparatus300is in the power saving mode and “valid” is set in the control table stored in the storage part340, the image forming apparatus300releases the power saving mode.

(Step S135) The communication part360of the image forming apparatus300transmits a response with respect to the transmission instruction to the terminal apparatus400. The response includes the response information C1stored in the storage part340. That is, the communication part360of the image forming apparatus300transmits the response information C1to the terminal apparatus400.

(Step S136) The image forming apparatus300responds to the transmission instruction on behalf of the image forming apparatus200. The response includes the response information B1stored in the storage part340. That is, the communication part360of the image forming apparatus300transmits the response information B1to the terminal apparatus400.

(Step S137) The image forming apparatus300responds to the transmission instruction on behalf of the image forming apparatus100. The response includes the response information A1stored in the storage part340. That is, the communication part360of the image forming apparatus300transmits the response information A1to the terminal apparatus400.

In this way, the image forming apparatus300responds to the transmission instruction on behalf of the image forming apparatuses100,200. Therefore, even when the terminal apparatus400transmits the transmission instruction, the image forming apparatuses100,200do not have to release the power saving mode. Since image forming apparatuses100,200do not release the power saving mode, power consumption can be suppressed. That the image forming apparatuses100,200do not release the power saving mode can improve power saving of the entire communication system.

Further, the image forming apparatus that performs proxy is an apparatus that transitions to the power saving mode last among the image forming apparatuses belonging to the multicast group. Therefore, the image forming apparatuses belonging to the multicast group may transition to the power saving mode in any order.

Next, communication processes executed by the image forming apparatuses100,200,300are described using a flow diagram. Further, the processes illustrated inFIG. 15are executed in the same way by the image forming apparatuses100,200,300. Therefore, inFIG. 15, a case where the image formation apparatus100executes the processes is described, and descriptions of cases where the image formation apparatuses200,300execute the processes are omitted.

FIG. 15is a flow diagram illustrating a transition process to the power saving mode. In the description ofFIG. 15,FIGS. 1, 3, 7, 8, and 11-13are referenced. Further, it is assumed that the image forming apparatus100is in the release mode. It is assumed that “valid” is set in the control table141.

(Step S11) The communication part160transmits a response instruction by multicasting.

(Step S12) The control part110determines whether or not a response with respect to the response instruction has been received. When a response with respect to the response instruction is received (Yes at Step S12), the control part110advances the process to Step S13. When a response with respect to the response instruction is not received (No at Step S12), the control part110advances the process to Step S16.

(Step S13) The control part110selects a representative image forming apparatus from image forming apparatuses that have transmitted responses.

(Step S14) The control part110transmits via the communication part160the response information A1to the representative image forming apparatus. Further, when response information of each of other image forming apparatuses is stored in the storage part140, the control part110transmits via the communication part160the response information of each of the other image forming apparatuses to the representative image forming apparatus. Further, the response information of each of the other image forming apparatuses may each be referred to as second response information.

(Step S15) The control part110sets “invalid” in the control table141.

(Step S16) The control part110executes a process to transition to the power saving mode. In this way, since the representative image forming apparatus acts on behalf of the image forming apparatus100, the image forming apparatus100does not have to release the power saving mode and respond to the transmission instruction. By not releasing the power saving mode, the image forming apparatus100can reduce the number of times the power saving mode is released.

In the embodiment, the case where the terminal apparatus400transmits a transmission instruction by multicasting has been described. However, the embodiment can also be applied to instructions other than the transmission instruction. For example, the terminal apparatus400transmits an update instruction of information stored in the image forming apparatuses100,200,300by multicasting. The image forming apparatus300transmits a completion response with respect to the update instruction to the terminal apparatus400on behalf of the image forming apparatuses100,200. As a result, the image forming apparatuses100and200do not have to release the power saving mode. The image forming apparatuses100,200each update the information after the power saving mode is released.

Further, in the embodiment, the case where the terminal apparatus400transmits a command by multicasting has been described. However, the embodiment can also be applied to a case where the terminal apparatus400transmits a command by broadcasting. In the broadcasting, the transmission instruction does not need to include any node of the image forming apparatus to designate destinations. All of apparatus, which are connected to the network, are expected to receive a transmission instruction that is sent by broadcasting even if none of nodes is included therein. For example, the image forming apparatus300stores the response information A1, the response information B1, and the response information C1. The image forming apparatuses100,200each set “invalid” in the control table so as not to respond even when the terminal apparatus400transmits a transmission instruction by broadcasting. When a transmission instruction transmitted by broadcasting by the terminal apparatus400is received, the image forming apparatus300responds to the transmission instruction on behalf of the image forming apparatuses100,200. That is, the image forming apparatus300transmits the response information A1and the response information B1to the terminal apparatus400.

Next, a release process of the power saving mode is described using a sequence diagram. For example, the release process of the power saving mode is executed afterFIG. 14. Further, the image forming apparatus300may perform the processes ofFIG. 13again and transitions to the power saving mode.

FIG. 16is a part1of a sequence diagram illustrating an example of a release process of the power saving mode. In the description ofFIGS. 16 and 17,FIGS. 1, 3-5 and 7are referenced. Further, it is assumed that the image forming apparatuses100,200,300are in the power saving mode. It is assumed that “invalid” is set in the control tables of the image forming apparatuses100,200,300. It is assumed that “valid” is set in the control table of the image forming apparatus300. It is assumed that the image forming apparatus300stores the response information A1and the response information B1.

(Step S141) The power saving handling part170of the image forming apparatus100performs transition preparation in order to transition to the release mode.

(Step S142) Before releasing the power saving mode, the power saving handling part170of the image forming apparatus100transmits a transmission instruction by multicasting in order to search for an image forming apparatus that stores the response information A1. The transmission instruction instructs transmission of the response information.

(Step S143) The power saving handling part270of the image forming apparatus200refers to the control table stored in the storage part240and detects that “invalid” is set. Therefore, the power saving handling part270of the image forming apparatus200does not respond to the transmission instruction. Further, the power saving handling part270of the image forming apparatus200does not release the power saving mode.

(Step S144) The power saving handling part370of the image forming apparatus300refers to the control table stored in the storage part340and detects that “valid” is set. The power saving handling part370of the image forming apparatus300executes a process to release the power saving mode. As a result, the image formation apparatus300transitions to the release mode.

(Step S145) The communication part360of the image forming apparatus300transmits a response with respect to the transmission instruction. The response includes the response information C1stored in the storage part340. That is, the communication part360of the image forming apparatus300transmits the response information C1to the image forming apparatus100.

(Step S146) The communication part360of the image forming apparatus300transmits a response with respect to the transmission instruction. The response includes the response information B1stored in the storage part340. That is, the communication part360of the image forming apparatus300transmits the response information B1to the image forming apparatus100.

(Step S147) The communication part360of the image forming apparatus300transmits a response with respect to the transmission instruction. The response includes the response information A1stored in the storage part340. That is, the communication part360of the image forming apparatus300transmits the response information A1to the image forming apparatus100.

(Step S148) The power saving handling part170of the image forming apparatus100detects that the response information A1exists among the response information A1, the response information B1, and the response information C1transmitted by the image forming apparatus300. That is, the power saving handling part170of the image forming apparatus100detects that the apparatus information of the image forming apparatus100exists among the response information transmitted by the image forming apparatus300. In this way, the power saving handling part170of the image forming apparatus100detects the image forming apparatus300that stores the response information A1from the plurality of image forming apparatuses that receive the transmission instruction transmitted by multicasting by the apparatus400.

FIG. 17is a part2of the sequence diagram illustrating the example of the release process of the power saving mode.

(Step S151) The power saving handling part170of the image forming apparatus100transmits a deletion instruction of the response information A1to the image forming apparatus300.

(Step S152) The control part310of the image forming apparatus300deletes the response information A1stored in the storage part340. Here,FIG. 18is described.FIG. 18illustrates a specific example of a case where the response information is deleted.FIG. 18illustrates that the response information A1is deleted from the storage part340.

Returning to the description ofFIG. 17, (Step S153) the power saving handling part170of the image forming apparatus100executes a process to release the power saving mode. As a result, the image formation apparatus100transitions to the release mode.

(Step S154) The control part110of the image forming apparatus100sets “valid” in the control table141.

Next, the release process of the power saving mode executed by each of the image forming apparatuses100,200,300is described using a flow diagram. Further, the processes illustrated inFIG. 19are executed in the same way by the image forming apparatuses100,200,300. Therefore, inFIG. 19, a case where the image formation apparatus100executes the processes is described, and descriptions of cases where the image formation apparatuses200,300execute the processes are omitted.

FIG. 19is a flow diagram illustrating a release process of the power saving mode. In the description ofFIG. 19,FIGS. 1, 3, 7, 16, and 17are referenced. Further, it is assumed that the image forming apparatus100is in the power saving mode. It is assumed that “invalid” is set in the control table141.

(Step S21) The power saving handling part170transmits via the communication part160a transmission instruction by multicasting in order to search for an image forming apparatus that stores the response information A1.

(Step S22) The power saving handling part170determines whether or not a response with respect to the transmission instruction has been received. When a response with respect to the transmission instruction is received (Yes at Step S22), the power saving handling part170advances the process to Step S23. When a response with respect to the transmission instruction is not received (No at Step S22), the power saving handling part170advances the process to Step S25.

(Step S23) The power saving handling part170determines whether or not that the response information A1exists among response information included in responses with respect to the transmission instruction has been detected. When that the response information A1exists has been detected (Yes at Step S23), the power saving handling part170advances the process to Step S24. When that the response information A1exists has not been detected (No at Step S23), the power saving handling part170advances the process to Step S25.

(Step S24) The power saving handling part170transmits via the communication part160a deletion instruction of the response information A1to the image forming apparatus that transmitted the response information A1. That is, the power saving handling part170transmits a deletion instruction of the response information A1to the representative image forming apparatus that responds on behalf of the image forming apparatus100.

(Step S25) The power saving handling part170executes a process to release the power saving mode.

(Step S26) The control part110sets “valid” in the control table141.

In this way, the image forming apparatus100causes the representative image forming apparatus to delete the response information A1. Then, the representative image forming apparatus stops responding on behalf of the image forming apparatus100by deleting the response information A1. Further, when a transmission instruction from the terminal apparatus400is received in the state of the release mode, the image forming apparatus100transmits a response including the response information A1to the terminal apparatus400. Therefore, even when the transmission instruction is transmitted by multicasting, the terminal apparatus400does not receive the response information A1in duplicate.

Also, when the representative image forming apparatus can be identified, without executing Steps S21-S23, the power saving handling part170may transmit via the communication part160a deletion instruction of the response information A1to the representative image forming apparatus. For example, before releasing the power saving mode, the power saving handling part170can identify the representative image forming apparatus by acquiring information indicating which image forming apparatus is the representative image forming apparatus from the image forming apparatus200or the image forming apparatus300.

The embodiment is described using image forming apparatuses. However, the image forming apparatus100, the image forming apparatus200, or the image forming apparatus300may also be a PC (Personal Computer), a server, or a portable device such as a smart phone that can be put in a power saving mode. That is, the embodiment may also be applied to a PC, a server, or a portable device.

In the above embodiments, any image forming apparatus has a function to detect if a transmission instruction, which is delivered thereto, is sent either by multicasting or by unicasting. In a case where a transmission instruction sent by unicasting is delivered to an image forming apparatus, the apparatus is designed to switch the power mode from a power saving to release regardless of the status of the (proxy) response function. Namely, even if an image processing apparats is at a power saving mode with the response function “invalid,” the image processing apparatus turns to a release mode when receiving a transmission instruction sent by unicasting. The detection for casting type can be embodied with software or hardware. Conventional network cards are available to practice the determination. InFIGS. 3-5, cast type detection parts110a,210aand310aare illustrated, which execute the cast type detection.

In general, the multicasting might mean to transmit a signal or packet to several terminals, all of which are designed in a header of the packet. However, in the invention, the term may be construed as transmitting the signal/packet to more than one terminal.