JP6862807B2 - Image forming device and program - Google Patents

Description

The present invention relates to an image forming apparatus such as an MFP (Multi-Functional Peripheral) and related techniques.

In recent years, in image forming devices such as MFPs, it has been required to further reduce power consumption in a power saving state.

In response to such a request, there is a technique for cutting off the power supply to the main CPU in the power saving state and operating the sub CPU having lower power consumption than the main CPU in the power saving state (patented). Reference 1 etc.). For example, the sub CPU acts on behalf of communication processing (specifically, a part thereof) for communication access from an external device via a communication network in a power saving state.

Japanese Unexamined Patent Publication No. 2015-22646

By the way, in such network communication, there are the following two types of access as access from an external device.

The first type of access (access by the first type of protocol) is a type of communication access that is completed in one response to a single packet. Examples of the first type of access include inquiries regarding name resolution. The second type of access (access by the second type of protocol) is a type of communication access that requires a response to a plurality of packets. Examples of the second type of access include communication access by TCP / IP.

For example, when the MFP receives an inquiry related to name resolution from another source device (communication partner), the MFP responds to the inquiry by returning the MAC address of its own device or the like to the source device. In the power saving state of the MFP, the response to such a first type of access is executed by the sub CPU instead of the main CPU. In FIG. 6 (see the top row), for the communication packet 701 (query A (name resolution)) by the name resolution protocol from a certain source device 80A, the sub CPU of the MFP is the query result instead of the main CPU. (MAC address, etc.) is returned to the source device 80A. That is, the sub CPU is performing a proxy response. Note that FIG. 6 is a diagram showing an operation according to a comparative example. Similarly, in response to the communication packet 801 (query B (name resolution)) from the source device 80B by the name resolution protocol, the sub CPU of the MFP transmits the query result (MAC address, etc.) on behalf of the main CPU. It is replying to the original device 80B.

On the other hand, when communication data (print data, etc.) by TCP / IP is transmitted from another source device, the communication data is divided into a plurality of packets and transmitted, and the MFP is originally relevant. It is required to execute response processing such as transmitting an acknowledgment (“ACK” signal) for each of a plurality of packets.

However, in the conventional MFP, there is no mechanism for taking over some packets for which the sub CPU has made a proxy response from the sub CPU to the main CPU in data communication that requires a response to a plurality of packets. In particular, in the second type of communication access (TCP / IP communication, etc.), although it is important to ensure the continuity of the sequence numbers in a plurality of packets, the continuity of the sequence numbers in the receiving device is ensured. There was no mechanism to secure it. Therefore, if the sub CPU makes a proxy response, the main CPU after the restart cannot know the sequence number of the packet received in the proxy response by the sub CPU before the main CPU is restarted, and the sub CPU cannot know the sequence number of the packet. The packet received by the CPU and the packet received by the main CPU cannot be properly integrated.

On the other hand, the sub CPU does not respond to the second type of communication access, restarts the main CPU, and the main CPU that has returned to the restarted state responds to the second type of communication access and the like. A technique for performing response processing (also referred to as a comparative example) can be considered.

However, when the sub CPU does not respond and the main CPU after restart responds, the time required for the predetermined number of retry processes in communication (for example, 2 seconds) is larger than the restart time of the main CPU (for example, 3 seconds). When it is short, a timeout may occur on the source device side.

FIG. 6 illustrates the situation in the technique according to the above-mentioned comparative example. Specifically, the device 80B (source device) requests three connection establishments (TCP / IP [SYN]) (more specifically, "TCP / IP [SYN] B1" and "TCP / IP [SYN]". ] B2 ”,“ TCP / IP [SYN] B3 ”), but if the reply (confirmation request (ACK), etc.) from the destination device (MFP) cannot be received at all, the judgment of“ timeout ”is made. It is done. In FIG. 6, even if the device 80 transmits a connection establishment request a predetermined number of times (here, 3 times) to the destination device (MFP, etc.), any reply (response) is sent from the destination device (MFP, etc.). It is assumed that the "timeout" is judged when the device does not return.

As shown in the vicinity of the middle stage of FIG. 6, the sub CPU of the MFP sets the communication packet (TCP / IP [SYN] A1) 501 of the TCP / IP to another device (source device) in the state where the power supply to the main CPU of the MFP is stopped. ) When receiving from 80A, the sub CPU sends a start request to the main CPU, but does not respond to the communication packet 501. Therefore, after a predetermined time (relatively long time (for example, 1.8 seconds)) has elapsed, the communication packet (TCP / IP [SYN] A2) 502 of the second connection establishment request is transmitted from the source device 80A to the MFP 10Z. Will be done. The sub CPU also does not respond to the communication packet (TCP / IP [SYN] A2) 502. Therefore, after a predetermined time (for example, 1.8 seconds) has elapsed, the communication packet (TCP / IP [SYN] A3) 503 of the third connection establishment request is further transmitted.

In addition, during the period during which the main CPU of the MFP is returning from the power supply stop state to the normal state (during the restart period), the sub CPU of the MFP performs a communication packet by TCP / IP (TCP / IP [SYN] B1). When 601 is received from another device (source device) 80B, the sub CPU does not respond to the communication packet 601. Therefore, after a predetermined time (here, a relatively short time (for example, 0.8 seconds)) has elapsed, the communication packet (TCP / IP [SYN] B2) 602 of the second connection establishment request is sent from the source device 80B to the MFP 10Z. Will be sent to. The sub CPU also does not respond to the communication packet (TCP / IP [SYN] B2) 602. Therefore, after a predetermined time (for example, 0.8 seconds) has elapsed, the communication packet (TCP / IP [SYN] B3) 603 of the third connection establishment request is further transmitted.

Here, as shown in FIG. 6, regarding the communication access from the device 80A, the restart of the main CPU has already been completed at the time of receiving the communication packet 503 of the third connection establishment request, and the main CPU has not been able to perform the communication access. A response process (specifically, an acknowledgment (“ACK” signal) transmission process, etc.) for the communication packet 503 is executed. In this case, since the device 80A can receive the acknowledgment, appropriate processing can be performed.

However, regarding the communication access from the device 80B, at the time of receiving the communication packet 603 of the third connection establishment request, the restart of the main CPU has not been completed yet, and both the sub CPU and the main CPU are in the communication packet 603. Does not respond. As a result, the device 80B cannot receive a reply (response) to any of the three connection establishment requests within a predetermined period, and the device 80B determines a "timeout".

In this way, when the time required for the retry process of a predetermined number of times in communication (for example, 2 seconds) is shorter than the restart time of the main CPU (for example, 3 seconds), a time-out occurs. Can be.

Considering such circumstances, it is conceivable to take countermeasures such as constructing an application so as not to use the second type protocol in the power saving state. However, such a countermeasure is not desirable.

Therefore, according to the present invention, in the image forming apparatus including the main CPU and the sub CPU, even after the main CPU shifts to the hibernation state, the communication is a communication access from another device and requires a response to a plurality of communication packets. The challenge is to provide technology that can appropriately accept access.

In order to solve the above problem, the invention of claim 1 is an image forming apparatus, in which a main CPU, a period during which the main CPU is in a hibernate state, and the main CPU returns from the hibernate state to a start state. In the first period including the return period in the middle of the process, the main CPU receives a specific type of access from an external device via a communication network and requires a response to a plurality of received packets. A sub CPU capable of surrogate response on behalf of the sub CPU, the sub CPU provides a surrogate response to the plurality of received packets related to the specific type of access in the first period, and the sub CPU. A sequence number is assigned to each of the plurality of received packets, and after the completion of returning to the activated state of the main CPU, a plurality of received packets assigned to the plurality of received packets within the first period with respect to the specific type of access. The latest number related to the sequence number is taken over by the main CPU.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the main CPU is one with respect to the latest value of the sequence number inherited from the sub CPU after returning to the activated state. It is characterized in that an incremented value is given to the next received packet in the specific type of access, and the reception operation of the remaining received packet in the specific type of access is taken over and executed.

A third aspect of the present invention is the image forming apparatus according to the first or second aspect of the present invention, in which the sub CPU receives the plurality of received packets related to the specific type of access in the first period. It is characterized in that, by returning an acknowledgment to the source device of the plurality of received packets, a proxy response is made with respect to the plurality of received packets.

The invention of claim 4 is the image forming apparatus according to the invention of claim 3, when the sub CPU receives the plurality of received packets relating to the specific type of access in the first period, the plurality of received packets. The data received by the received packet is stored in the receive buffer, and when the main CPU returns to the activated state, the sub CPU acquires the data stored in the receive buffer.

The invention of claim 5 is the image forming apparatus according to any one of claims 1 to 4, wherein the sub CPU uses a sequence number of a received packet in the specific type of access from a plurality of different devices. It is characterized in that each of the plurality of devices is managed individually.

In the invention of claim 6, the sub CPU built in the image forming apparatus has a) a period during which the main CPU of the image forming apparatus has a hibernation state and the main CPU has returned from the hibernation state to the starting state. In the first period including the return period in the middle, for the plurality of received packets relating to the specific type of access from the external device via the network and requiring a response to the plurality of received packets. And a step of assigning a sequence number to each of the plurality of received packets, and b) a plurality of sequence numbers assigned to the plurality of received packets within the first period for the specific type of access. It is a program for executing a step of taking over the latest number related to the main CPU to the main CPU after the completion of returning to the booted state of the main CPU.
The invention of claim 7 is characterized in that, in the image forming apparatus according to any one of claims 1 to 5, the specific type of access is a communication access by TCP / IP.
The invention of claim 8 is characterized in that, in the program according to the invention of claim 6, the specific type of access is a communication access by TCP / IP.

According to the inventions of claims 1 to 8 , the sub CPU performs a specific type of access requiring a response to a plurality of received packets in a first period including a pause period and a return period of the main CPU. The proxy response is made, and the latest information on the plurality of sequence numbers given to the plurality of received packets in the specific type of access is inherited by the main CPU after the return. Therefore, even after the main CPU shifts to the hibernation state, it is possible to appropriately accept communication access from another device that requires a response to a plurality of communication packets.

It is a figure which shows the functional block of the MFP (image forming apparatus). It is an external view of the MFP. It is a figure which shows the state in the power supply stop period of a main CPU. It is a figure which shows the operation of the return period of a main CPU. It is a timing chart which shows the operation which concerns on embodiment. It is a timing chart which shows the operation which concerns on a comparative example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1. Device configuration>
FIG. 1 is a diagram showing a functional block of the image forming apparatus 10. Here, as the image forming apparatus 10, an MFP (Multi-Functional Peripheral) is illustrated. Further, FIG. 2 is an external view of the MFP 10.

The MFP 10 is a device (also referred to as a multifunction device) having a scanning function, a copying function, a facsimile function, a box storage function, and the like. Specifically, as shown in the functional block diagram of FIG. 1, the MFP 10 includes an image reading unit 2, a print output unit 3, a communication unit 4, an operation panel unit 22, a main system controller 20, a subsystem controller 40, and a power supply. A part 36 and the like are provided, and various functions are realized by operating each of these parts in a complex manner. The MFP 10 is also referred to as an information processing device.

The image reading unit 2 is a processing unit that optically reads (that is, scans) a document placed at a predetermined position of the MFP 10 to generate image data (also referred to as a document image or a scanned image) of the document. is there. The image reading unit 2 is also referred to as a scanning unit.

The print output unit 3 is an output unit that prints and outputs an image on various media such as paper based on data related to a print target.

The communication unit 4 is a processing unit capable of performing facsimile communication via a public line or the like. Further, the communication unit 4 can also perform communication (network communication) via the communication network. The communication unit 4 can perform network communication with other devices (80A, 80B (see FIG. 2), etc.). Examples of other devices include personal computers and / or MFPs.

As shown in FIG. 2, the operation panel unit 22 is an operation unit having a touch panel 22b on the front side thereof. The touch panel 22b is configured by embedding various sensors and the like in a liquid crystal display panel, and can display various information and receive various operation inputs from the operator. In other words, the touch panel 22b is not only a display unit for displaying various information but also an operation input unit for receiving operation input from the user.

The main system controller 20 is a control device that is built in the MFP 10 and controls the MFP 10 in an integrated manner. The main system controller 20 includes a main CPU 31 and the like. The main CPU 31 and various semiconductor memories (volatile memory (main memory) 32 such as RAM, non-volatile memory 33 such as eMMC (embedded Multi Media Card)) and the like constitute a computer system. The main system controller 20 realizes various processing units by executing a predetermined software program (hereinafter, also simply referred to as a program) stored in the non-volatile memory 33 in the main CPU 31. Further, the program (specifically, a program module group) may be installed in the MFP 10 via a communication network. Alternatively, the program may be recorded on a portable recording medium such as a USB memory, read from the recording medium, and installed in the MFP 10.

The power supply unit 36 has an AC-DC conversion unit (not shown), and uses the AC-DC conversion unit to transfer power from the AC power supply (power after DC conversion) to each unit (main CPU 31) of the MFP 10. , Volatile memory 32, 43, non-volatile memory 33, 45, sub CPU 41, and other processing units). Further, the power supply unit 36 has a power control IC 38. The power control IC 38 is an IC that controls the power supply to each part of the MFP 10. The power control IC 38 controls the power supply to each part of the MFP 10 in cooperation with the main CPU 31, the sub CPU 41 (described below), and the like.

The MFP 10 is also provided with a sub CPU 41. In the sleep state (power saving state) of the MFP 10, the power supply to the main CPU 31 and the like is stopped, while the power is supplied to the sub CPU 41, and the sub CPU 41 performs various operations (monitoring process, judgment process, etc.). ) Can be executed. For example, the sub CPU 41 can control the communication operation with the external device. More specifically, the sub CPU 41 is the main CPU 31 with respect to access (network access) from another device (external device) via the communication network during the power supply stop period and the return period (described later) to the main CPU 31. It is possible to respond by proxy (proxy response).

The sub CPU 41 and various semiconductor memories (SRAM, flash ROM, etc.) constitute a computer system. The sub CPU 41 realizes various processing units (communication control unit, etc.) by executing a predetermined program stored in the non-volatile memory 45 (flash ROM, etc.) under its control. The communication control unit controls the communication operation with the external device. Further, the program (specifically, a program module group) may be installed in the MFP 10 via a communication network. Alternatively, the program may be recorded on a portable recording medium such as a USB memory, read from the recording medium, and installed in the MFP 10.

The MFP 10 is also provided with an SRAM (static RAM) 43. As will be described later, during the pause period, the return period, and the like of the main CPU 31, the sequence number, the proxy reception data, and the like are stored in the SRAM 43 by the sub CPU 41. The SRAM 43 functions as a receive buffer. Further, after the power supply to the main CPU 31 is resumed and the main CPU 31 returns to the activated state, the information stored in the SRAM 43 is transferred to the main memory 32 (via the expansion bus PCIe (see FIG. 4) or the like). Used by the main CPU 31.

<2. Operation>
<2-1. Proxy period T1 (main CPU 31 power supply stop period and return period)>
When the MFP 10 transitions from the normal operation state Q1 to the power saving state (sleep state, etc.) Q2, the main CPU 31 starts the snapshot data acquisition process. Then, when the snapshot data acquisition process is completed, the main CPU 31 transfers the subsequent processing authority to the sub CPU 41. Then, the main CPU 31 sends a power supply stop command to itself to the power supply unit 36. In response to this, the power supply unit 36 stops the power supply to almost all the processing units including the main CPU 31 and the like, and shifts the MFP 10 to the power saving state Q2 (see FIG. 3).

As shown in FIG. 3, in the power saving state Q2, the power supply to the main CPU 31 and the main memory 32 is stopped.

However, in the power saving state Q2, power is supplied to the sub CPU 41 and the SRAM 43. The sub CPU 41 may perform a proxy response of the main CPU 31 to a network access from another device during a power supply stop period (also referred to as a pause period of the main CPU 31) to the main CPU 31 and a subsequent return period (described later). It is possible. In other words, the sub CPU 41 receives the communication from each external device (source device) during the proxy period (the period in which the processing authority is transferred from the main CPU 31 to the sub CPU 41 and executes the process on behalf of the user). It is possible to make a proxy response regarding communication. The power consumption of the sub CPU 41 and the like is less than the power consumption of the main CPU 31 and the like. Therefore, by operating the sub CPU 41 (instead of the main CPU 31) in the power saving state Q2, it is possible to reduce the power consumption as compared with the case of operating the main CPU 31 in the power saving state Q2.

During the proxy period T1 (a period including a power supply stop period T11 for the main CPU 31 and a subsequent return period T12 (see FIGS. 3 and 5)), the sub CPU 41 communicates with the device (MFP) 10 (10Z). The response process (proxy response process) that responds to the access on behalf of the main CPU 31 is executed. As will be described later, when communication access to the MFP 10 is performed from an external device (80A, 80B, etc.), the sub CPU 41 substitutes for the main CPU 31 with respect to both the first type of access and the second type of access. Execute the response processing (surrogate response processing) that responds with. In this respect (the point that the sub CPU 41 responds by proxy not only to the first type of access but also to the second type of access), the present embodiment is different from the above-mentioned comparative example.

As described above, the first type of access (access by name resolution protocol or the like) is a type of communication access that is completed by one response to a single communication packet. Examples of the first type of access include inquiries regarding name resolution. The second type of access is a type of communication access that requires a response to a plurality of packets. Examples of the second type of access include communication access by TCP / IP. The second type of access is also expressed as a type of access in which data is transmitted by dividing it into a plurality of received packets.

More specifically, as shown in FIG. 5, in the proxy period T1 (the period including the power supply stop period T11 for the main CPU 31 and the subsequent return period T12), the sub CPU 41 receives the first type of access. In addition to making a proxy response, it also makes a proxy response to a second type of access (access that requires a response to a plurality of communication packets (received packets)).

First, for the first type of access (access by the first type of protocol), the same operation (reply processing of MAC address and the like) as in the above-mentioned comparative example and the like is executed. In short, the proxy response operation by the sub CPU 41 is executed. For example, as the first type of access, when a name resolution protocol query (packets 701,801, etc.) is received from another device (80A, 80B, etc.), the MFP10 (10Z) receives the MAC address of its own device 10Z. Etc. are returned to the source device (80A, 80B, etc.) to respond to the inquiry (proxy response).

On the other hand, for the second type of access (access by the second type of protocol), an operation different from the above-mentioned comparative example is executed. For example, when the MFP 10 (sub CPU 41) receives a communication access by TCP / IP from another device (80A, 80B, etc.), it receives a proxy response process (specifically, an acknowledgment (ACK signal)) for the communication access. Processing, etc.) is performed.

When the sub CPU 41 of the MFP 10 receives each communication packet related to communication access by TCP / IP during the proxy period T1 of the main CPU 31 of the MFP 10, it acknowledges and responds to the source device (80A, 80B, etc.) related to each communication packet. By replying (“ACK” signal) or the like, a response (proxy response) is made to each communication packet by TCP / IP.

More specifically, when a communication packet (“SYN” signal) (101, 201, etc.) for establishing communication is first transmitted from the source device, the MFP 10Z (sub CPU 41) receives the “SYN” signal. An acknowledgment (“ACK” signal) is returned to. Subsequently, when a plurality of data packets (communication packets indicating the data contents) are sequentially transmitted from the source device, the MFP 10Z (sub CPU 41) acknowledges (“ACK”) the plurality of received data packets. "Signal) is returned. In this way, the sub CPU 41 returns an acknowledgment in response to the communication access by TCP / IP (specifically, the plurality of packets thereof).

Further, in this embodiment, the sub CPU 41 sequentially assigns sequence numbers (serial numbers) to each of the plurality of received packets related to the second type of access from each source device. The sequence number does not have to start from No. 1 (or No. 0), but may start from an appropriate number. Further, the sequence number may be a number irrelevant to the sequence number used in the main CPU before the transition to the power saving state of the main CPU (a number independently assigned by the sub CPU 41). The sequence number is a management sequence number of the received packet, and is assigned and managed by the sub CPU 41. Further, the sequence number is assigned and managed for each source device and each access.

For example, for the received packets related to TCP / IP communication transmitted from the device 80A, serial numbers starting with "101" are sequentially assigned, and for the received packets related to TCP / IP communication transmitted from the device 80B. Therefore, consecutive numbers starting with another number "201" are sequentially assigned. A different number "701" or the like is assigned to the received packet related to the name resolution protocol transmitted from the device 80A, and further to the received packet related to the name resolution protocol transmitted from the device 80B. Another number "801" or the like is assigned. In this way, different sequence numbers are assigned to each source device and each access (type).

Further, in the proxy period T1, the latest sequence number (latest sequence number for each source device) regarding the second type of access from each source device is stored in the SRAM 43 by the sub CPU 41.

For example, when the sequence number "101" is assigned to the communication packet 101 ("TCP / IP [SYN] A1") from a certain source device 80A, the time when the communication packet 101 is received is corresponding to the sequence number "101". "101" is stored in the SRAM 43 as the latest sequence number (latest information "latest sequence number" among a plurality of sequence numbers related to access from the source device 80A).

After that, the sequence number "102" (value obtained by incrementing the immediately preceding "101" by one) is assigned to the next communication packet 102 ("TCP / IP [data] A2") from the same source device 80A. To. In response to this, "102" is stored in the SRAM 43 as the latest sequence number (latest sequence number regarding access from the source device 80A) at the time of receiving the communication packet 102.

On the other hand, the sequence number "201" of another system is assigned to the communication packet 201 ("TCP / IP [SYN] B1") from another source device 80B. In response to this, "201" is stored in the SRAM 43 as the latest sequence number (latest information "latest sequence number" among the plurality of sequence numbers related to access from the source device 80B) at the time of receiving the communication packet 201. ..

Similarly, after that, for the next communication packet 202 (“TCP / IP [data] B2”) from the other source device 80B, the sequence number “202” (immediately preceding “201” is incremented by one. Value) is given. In response to this, "202" is stored in the SRAM 43 as the latest sequence number (latest sequence number regarding access from the source device 80B) at the time of receiving the communication packet 202.

When data is received in the proxy response by the sub CPU 41, the received data (proxy reception data) is stored in the SRAM 43. For example, the data received in the communication packet 102, the data received in the communication packet 202, and the like are stored in the SRAM 43. Further, the proxy reception data for each packet is stored in the SRAM 43 in association with the sequence number assigned to each packet by the sub CPU 41.

As will be described later, the information (latest sequence number and proxy reception data) stored in the SRAM 43 is passed from the sub CPU 41 to the main CPU 31 via the SRAM 43 after the main CPU 31 returns to the activated state. Used by the main CPU 31.

Further, in this embodiment, the sub CPU 41 determines that the main CPU 31 should be restarted when the second type of access is first received in the proxy period T1. In FIG. 5, when a communication packet 101 (“TCP / IP [SYN] A1”) from a certain source device 80A is received, it is determined that the main CPU 31 should be restarted. Then, the sub CPU 41 sends a restart command for the main CPU 31 (a return command for returning the main CPU 31 to the started state) (also referred to as a start request for the main CPU 31) to the main CPU 31 and the power supply unit 36. The power supply unit 36 restarts the power supply to the main CPU 31, the main memory 32, and the like, and the main CPU 31 starts the restart operation (see FIG. 4).

The main CPU 31 can be started (restarted) at high speed by using, for example, snapshot data stored in the non-volatile memory 33. The time required for the restart operation by high-speed startup using the snapshot data is shorter (for example, about several seconds) than the time required for the normal restart operation without using the snapshot data (for example, about several tens of seconds).

During the recovery period (for example, several seconds to several tens of seconds (here, about 3 seconds)) until the main CPU 31 returns from the power supply stop state to the start state (until the restart is completed) by the restart process, the sub CPU 41 is used. Response processing (proxy response processing) for various communication accesses is executed on behalf of the main CPU 31.

<2-2. After the restart of the main CPU 31 is completed (after the agency period T1 ends)>
After that, when the main CPU 31 returns to the activated state, the return completion notification is sent to the sub CPU 41, and when the sub CPU 41 receives the return completion notification, the proxy authority is returned to the main CPU 31 (authority is transferred to the main CPU 31). To do). The main CPU 31 again executes a normal operation (including a network communication operation).

With the completion of the transfer of authority, the sub CPU 41 stops the communication operation with the other device. On the other hand, the main CPU 31 continues the operation of receiving the remaining received packets related to the second type of access based on the information received from the sub CPU 41 (the "latest sequence number" inherited from the sub CPU 41 via the SRAM 43). In other words, the main CPU 31 takes over the reception operation of the remaining received packets from the sub CPU 41 and executes the operation. Specifically, the main CPU 31 assigns a number incremented by 1 to each latest sequence number received from the sub CPU 41 to each of the following received packets, and continues the receiving operation.

When the main CPU 31 returns to the restarted state, the information (each latest sequence number and each received data) stored in the SRAM 43 is transferred to the main memory 32 and used by the main CPU 31. In other words, the main CPU 31 inherits the latest information (latest sequence number) regarding the plurality of sequence numbers given to the received packet in the second type of access to the main CPU after the return via the SRAM 43.

For example, the main CPU 31 receives the latest sequence number “102” from the sub CPU 41 via the SRAM 43 for TCP / IP communication (“TCP / IP [data] Ai”) from the source device 80A. Then, the main CPU 31 assigns the sequence number "103" (a value obtained by incrementing the immediately preceding "102" by one) to the next communication packet 103 ("TCP / IP [data] A3") from the source device 80A. Give. Further, "103" is stored in the main memory 32 as the latest sequence number (latest sequence number related to access from the source device 80A) at the time of receiving the communication packet 103. The same reception processing may be performed for the new communication packets 104, 105, ... After that.

Similarly, the main CPU 31 receives the latest sequence number “202” from the sub CPU 41 via the SRAM 43 for TCP / IP communication (“TCP / IP [data] Bi”) from the source device 80B. Then, the main CPU 31 assigns the sequence number "203" (a value obtained by incrementing the immediately preceding "202" by one) to the next communication packet 203 ("TCP / IP [data] B3") from the source device 80B. Give. Further, "203" is stored in the main memory 32 as the latest sequence number (latest sequence number related to access from the source device 80B) at the time of receiving the communication packet 203. The same reception processing may be performed for the new received packets 204, 205, ... After that.

Further, in the TCP / IP communication, the main CPU 31 restores data based on a plurality of communication packets based on a sequence number stored in association with each received data for each communication packet. In other words, the correspondence between the received data for each packet and the sequence number assigned by the sub CPU 41 and the main CPU 31 for each packet is also used. As a result, for example, correct overall data (print data, etc.) is restored based on the data of each packet to which the sequence numbers "102", "103", .. are assigned. At this time, the information (each latest sequence number and received data) stored in the SRAM 43 is transferred to the main memory 32 and used by the main CPU 31. As a result, the main CPU 31 can acquire correct data (transmission data (for example, print data) from the device 80A) that accurately reflects the data received by the sub CPU 41 as a proxy before returning.

Similarly, the main CPU 31 rearranges the received data in each communication packet of the sequence numbers “202”, “203”, ... In the original transmission order and restores the correct data. At this time, the information (each latest sequence number and received data) stored in the SRAM 43 is transferred to the main memory 32 and used by the main CPU 31. According to this, the main CPU 31 can acquire correct data (transmission data from the device 80B) that accurately reflects the data received by the sub CPU 41 as a proxy before returning.

<2-3. Effects in the embodiment>
According to the above operation, the sub CPU 41 also responds by proxy to the second type of access that requires a response to a plurality of received packets during the proxy period T1. Then, the latest information (latest number) among the plurality of sequence numbers given to the received packet in the second type of access is taken over by the main CPU 31 after the restoration is completed. Therefore, regarding the second type of access from a certain device (for example, 80B), the packet received from the transition to the power supply stop state of the main CPU 31 to the completion of restart (before the completion of recovery) (in the proxy period T1). It is possible to ensure the continuity between the sequence number of the received packet) and the sequence number of the packet subsequently received by the main CPU 31 after the restart is completed (after the recovery is completed). Therefore, even after the main CPU 31 shifts to the hibernation state, it is possible to appropriately accept communication access from an external device (80A, 80B, etc.) that requires a response to a plurality of communication packets.

In particular, since the sub CPU 41 returns an acknowledgment (ACK) on behalf of the second type of access during the power supply stop period and the return period to the main CPU 31, the source device 80B or the like that has received the acknowledgment. Can immediately send the next packet without retrying. Therefore, it is possible to avoid the time-out determination being performed and to appropriately proceed the data transmission by a plurality of packets without stagnation.

Here, TCP / IP communication is illustrated as the second type of access, but the present invention is not limited to this, and other various types of communication (communication using other data transfer protocols, etc.). You may. Further, when communication of a plurality of different protocols is performed as the second type of access, the sequence number may be managed for each protocol.

<3. Deformation example, etc.>
Although the embodiments of the present invention have been described above, the present invention is not limited to the contents described above.

For example, in the above embodiment, the sub CPU 41 responds to each of a plurality of received packets individually, but the sub CPU 41 is not limited to this, and the sub CPU 41 may use some received packets (for example, two received packets). ) May be collectively answered (acknowledgement response, etc.).

Further, in the above embodiment, when the sub CPU 41 receives the second type of access during the proxy period T1, it acknowledges (normally receives the data) to the source device related to the second type of access. By returning an ACK signal to that effect), a response (proxy response) is made to the second type of access, but the present invention is not limited to this.

For example, when the sub CPU 41 receives the second type of access during the power supply stop period for the main CPU 31, the sub CPU 41 makes a substantial standby request (weight command, etc.) to the source device for the second type of access. By replying, a response (proxy response) may be made to the second type of access. In other words, the sub CPU 41 may make a reply (response) to the source device while suppressing data transmission from the source device.

Specifically, the sub CPU 41 may transmit, for example, a reply having a setting change of the window size (Window Size) in TCP / IP communication to zero as a "weight command". More specifically, as a response to the packet 101 (, 201, etc.) (see FIG. 5), "ACK having the effect that the window size has been changed to zero" is sent from the MFP 10 to the device 80A (, 80B, etc.). It should be sent to.

According to the reply that the window size is set to zero is sent to the source device (80), the destination device (MFP) has data due to insufficient free space in the receive buffer memory of the destination device. It is possible to convey to the source device (80) that reception is not possible. This makes it possible to suppress data transmission from the source device (80).

Upon receiving the reply that the window size is set to zero, the source device (80) transmits a transmission request of a new window size to the MFP (destination device) after waiting for a certain period of time.

At this time, if the return of the main CPU 31 of the MFP to the activated state has not been completed yet, the sub CPU 41 receives the transmission request and still returns "zero" as a new window size. As a result, data transmission suppression from the source device is continued.

On the other hand, at this time, if the return to the activated state of the main CPU 31 of the MFP has already been completed, the main CPU 31 receives the transmission request and sets a new window size of "a value larger than zero" (for example, a value larger than zero). Send (a few kilobytes). According to this, the data transmission from the source device can be restarted.

In this way, the sub CPU 41 may make a reply (response) to the source device while suppressing data transmission from the source device.

Further, in such a case, in the proxy period T1, the source device (80B or the like) receives the "weight command" as a response to the packet transmission, and some reply (response) from the destination device (MFP). ) Is being received. Therefore, the source device (80B or the like) does not perform the timeout determination. After that, when the transmission / reception (request for transmission of a new window size, etc.) related to the weight command is repeated several times, the restart of the main CPU 31 has already been completed. Therefore, normal communication can be continued. In this case, the process of receiving the data from the external device may be performed by the main CPU 31 after the return of the main CPU 31, for example.

10 MFP (Image Forming Device)
31 main CPU
32 Main memory 41 Sub CPU
43 SRAM (Static RAM)
80A, 80B Source device (external device)
T1 agency period T11 power supply stop period T12 return period

Claims (8)

It is an image forming device
With the main CPU
A specific period via a communication network from an external device in a first period including a period in which the main CPU is in a hibernation state and a return period in which the main CPU is in the process of returning from the hibernation state to the start state. A sub CPU that can make a proxy response on behalf of the main CPU for a specific type of access that is a type of access and requires a response to a plurality of received packets.
With
The sub CPU
In the first period, a proxy response is made to the plurality of received packets related to the specific type of access, and a sequence number is assigned to each of the plurality of received packets.
After the return to the activated state of the main CPU is completed, the latest numbers related to the plurality of sequence numbers assigned to the plurality of received packets within the first period for the specific type of access are taken over by the main CPU. An image forming apparatus characterized by. In the image forming apparatus according to claim 1,
After returning to the started state, the main CPU assigns a value incremented by 1 to the latest value of the sequence number inherited from the sub CPU to the next received packet in the specific type of access. An image forming apparatus that takes over and executes the reception operation of the remaining received packets in the specific type of access. In the image forming apparatus according to claim 1 or 2.
When the sub CPU receives the plurality of received packets related to the specific type of access in the first period, the sub CPU returns an acknowledgment to the source device of the plurality of received packets, thereby causing the plurality of received packets. An image forming apparatus characterized in that it responds by proxy with respect to a received packet of. In the image forming apparatus according to claim 3,
When the sub CPU receives the plurality of received packets related to the specific type of access in the first period, the sub CPU stores the data received by the plurality of received packets in the reception buffer.
An image forming apparatus, characterized in that, when the main CPU returns to the activated state, the sub CPU acquires data stored in the reception buffer. In the image forming apparatus according to any one of claims 1 to 4.
The sub-CPU is an image forming apparatus that individually manages sequence numbers of received packets in the specific type of access from a plurality of different devices for each of the plurality of devices. In the sub CPU built into the image forming device,
a) A network from an external device in a first period including a period in which the main CPU of the image forming apparatus is in a hibernation state and a return period in which the main CPU is in the process of returning from the hibernation state to the startup state. A proxy response is made to the plurality of received packets related to a specific type of access that requires a response to a plurality of received packets, and a sequence number is assigned to each of the plurality of received packets. Steps to do and
b) The latest numbers relating to the plurality of sequence numbers assigned to the plurality of received packets within the first period for the specific type of access are sent to the main CPU after the return to the activated state of the main CPU is completed. Steps to take over and
A program to execute. In the image forming apparatus according to any one of claims 1 to 5.
An image forming apparatus, wherein the specific type of access is a communication access by TCP / IP. In the program according to claim 6,
The specific type of access is a program characterized by being a communication access by TCP / IP.

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