JP2018089895A - Image formation apparatus and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of properly receiving a specific type of access requiring a response to a plurality of communication packets even after a main CPU is shifted to the idle state in an image formation apparatus including the main CPU and a sub CPU.SOLUTION: A sub CPU of a MFP performs a proxy response to a plurality of reception packets for the specific type of access (TCP/IP communication or the like) through the network from an external device in a proxy period T1 (including the idle period (power supply stop period or the like) and recovery period (restart period or the like) of a main CPU). The sub CPU gives the sequence number to each of the plurality of reception packets related to the specific type of access. The sub CPU 41 transfers the newest number related to the plurality of sequence numbers given in the proxy period T1 to the plurality of reception packets to the main CPU after recovery completion to the activation state of the main CPU.SELECTED DRAWING: Figure 5

Description

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

  In recent years, image forming apparatuses such as MFPs are required to further reduce power consumption in a power saving state.

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

Japanese Patent Laid-Open 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 with a single response to a single packet. Examples of the first type of access include queries related to name resolution. The second type access (access by the second type protocol) is a type of communication access that requires responses 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 transmission source device (communication partner), the MFP responds to the inquiry by returning its own MAC address or the like to the transmission source device. In the power saving state of the MFP, such a response to the first type of access is executed by the sub CPU instead of the main CPU. In FIG. 6 (see the top row), for a communication packet 701 (inquiry A (name resolution)) by a name resolution protocol from a certain transmission source device 80A, the sub CPU of the MFP replaces the main CPU with the inquiry result. (MAC address or the like) is returned to the transmission source device 80A. That is, the sub CPU performs a proxy response. FIG. 6 is a diagram illustrating an operation according to a comparative example. Similarly, in response to a communication packet 801 (query B (name resolution)) by the name resolution protocol from the transmission source device 80B, the sub CPU of the MFP transmits a query result (MAC address or the like) instead of the main CPU. It is returned to the original device 80B.

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

  However, in the conventional MFP, in data communication that requires responses to a plurality of packets, there is no mechanism for taking over from the sub CPU to the main CPU for some of the packets for which the sub CPU has made a proxy response. In particular, in the second type of communication access (TCP / IP communication, etc.), it is important to ensure the continuity of sequence numbers in a plurality of packets. There was no collateral mechanism. For this reason, 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 restarts. Packets received by the CPU and packets received by the main CPU cannot be appropriately 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 does not respond to the second type of communication access. Thus, a technique for performing response processing (also referred to as a comparative example) can be considered.

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

  In FIG. 6, the said situation in the technique which concerns on the above-mentioned comparative example is illustrated. Specifically, the device 80B (source device) makes three connection establishment requests (TCP / IP [SYN]) (more specifically, “TCP / IP [SYN] B1”, “TCP / IP [SYN] ] B2 ”,“ TCP / IP [SYN] B3 ”), and if a reply (confirmation request (ACK), etc.) from the destination device (MFP) is not received at all, a“ timeout ”decision is made. Has been done. In FIG. 6, even if the connection establishment request is transmitted a predetermined number of times (here, 3 times) from the device 80 to the transmission destination device (MFP, etc.), any reply (response) from the transmission destination device (MFP, etc.). It is assumed that a “timeout” determination is made when no return is made.

  As shown in the middle part of FIG. 6, when the power supply to the main CPU of the MFP is stopped, the sub CPU of the MFP separates the TCP / IP communication packet (TCP / IP [SYN] A1) 501 from another device (sender device). When receiving from 80A, the sub CPU sends an activation 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, a communication packet (TCP / IP [SYN] A2) 502 for the second connection establishment request is transmitted from the transmission source device 80A to the MFP 10Z. Is done. The sub CPU does not respond to the communication packet (TCP / IP [SYN] A2) 502. Therefore, after a predetermined time (for example, 1.8 seconds) elapses, a communication packet (TCP / IP [SYN] A3) 503 for the third connection establishment request is further transmitted.

  In addition, during the period when 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 transmits a TCP / IP communication packet (TCP / IP [SYN] B1). When receiving 601 from another apparatus (transmission source apparatus) 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, a communication packet (TCP / IP [SYN] B2) 602 for the second connection establishment request is sent from the transmission source device 80B to the MFP 10Z. 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) elapses, a communication packet (TCP / IP [SYN] B3) 603 for the third connection establishment request is further transmitted.

  Here, as shown in FIG. 6, regarding the communication access from the device 80A, at the time of receiving the communication packet 503 of the third connection establishment request, the restart of the main CPU has already been completed. Response processing for the communication packet 503 (specifically, processing for transmitting an acknowledgment (“ACK” signal) or the like) is executed. In this case, since the device 80A can receive the confirmation response, an appropriate process can be performed.

  However, regarding the communication access from the device 80B, at the time of receiving the communication packet 603 for the third connection establishment request, the restart of the main CPU has not been completed yet, and neither the sub CPU nor the main CPU has received the communication packet 603. Do not respond. As a result, the device 80B cannot receive a reply (response) to any of the three connection establishment requests within the predetermined period, and the device 80B determines “timeout”.

  As described above, there is a problem that a timeout occurs when the time required for the retry processing for a predetermined number of times (for example, 2 seconds) in communication is shorter than the restart time (for example, 3 seconds) of the main CPU. Can do.

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

  Therefore, according to the present invention, in an image forming apparatus including a main CPU and a sub CPU, communication that is a communication access from another apparatus and requires responses to a plurality of communication packets even after the main CPU shifts to a sleep state. It is an object of the present invention to provide a technology that can appropriately accept access.

  In order to solve the above-mentioned problem, the invention of claim 1 is an image forming apparatus, wherein a main CPU, a period during which the main CPU is in a dormant state, and the main CPU is returned from the dormant state to an activated state. The main CPU for a specific type of access that requires a response to a plurality of received packets in a first period including a return period in the middle of A sub CPU capable of performing proxy response on behalf of the sub CPU, wherein the sub CPU performs proxy response to the plurality of received packets related to the specific type of access in the first period, and A sequence number is assigned to each of a plurality of received packets, and after the return to the activated state of the main CPU is completed, the specific number A plurality of the latest number for the sequence number assigned to the plurality of received packets in the first period for access class, wherein to take over the main CPU.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the invention, the main CPU has one for the latest value of the sequence number taken over from the sub CPU after returning to the activated state. The incremented value is assigned to the next received packet in the specific type of access, and the reception operation of the remaining received packets in the specific type of access is taken over and executed.

  According to a third aspect of the invention, in the image forming apparatus according to the first or second aspect of the invention, the sub CPU receives the plurality of received packets related to the specific type of access in the first period. A proxy response is made for the plurality of received packets by returning an acknowledgment to the transmission source device of the plurality of received packets.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect of the invention, when the sub CPU receives the plurality of received packets related to the specific type of access in the first period, The data received by the reception packet is stored in the reception buffer, and the main CPU acquires the data stored in the reception buffer by the sub CPU when returning to the activated state.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the sub CPU sets a sequence number of a received packet in the specific type of access from a plurality of different apparatuses. Each of the plurality of devices is individually managed.

  According to a sixth aspect of the present invention, in the sub CPU incorporated in the image forming apparatus, a) a period in which the main CPU of the image forming apparatus has a hibernation state and the main CPU has returned from the hibernation state to an activated state. For a plurality of received packets related to a specific type of access that requires a response to a plurality of received packets that is a specific type of access from an external device via a network in a first period including an intermediate return period And b) 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. The latest number related to the main CPU is taken over to the main CPU after completion of the return of the main CPU to the startup state. Characterized in that it is a program for executing the steps, the.

  According to the first to sixth aspects of the present invention, the sub CPU performs a specific type of access that requires responses to a plurality of received packets in the first period including the pause period and the return period of the main CPU. In response to the proxy, the latest information regarding the plurality of sequence numbers assigned to the plurality of received packets in the specific type of access is taken over by the restored main CPU. Therefore, even after the main CPU shifts to the dormant state, it is possible to appropriately accept a communication access that is a communication access from another device and requires a response to a plurality of communication packets.

2 is a diagram illustrating functional blocks of an MFP (image forming apparatus). FIG. 1 is an external view of an MFP. It is a figure which shows the mode in the electric power supply stop period of main CPU. It is a figure which shows operation | movement of the return period of main CPU. It is a timing chart which shows the operation concerning an embodiment. It is a timing chart which shows the operation | movement 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 illustrating functional blocks of the image forming apparatus 10. Here, an MFP (Multi-Functional Peripheral) is exemplified as the image forming apparatus 10. FIG. 2 is an external view of the MFP 10.

  The MFP 10 is a device (also referred to as a multi-function device) having a scan function, a copy 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 source. The unit 36 and the like are provided, and various functions are realized by operating these units in combination. The MFP 10 is also referred to as an information processing apparatus.

  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 and generates 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 out 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. Furthermore, the communication unit 4 can also perform communication (network communication) via a 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 also 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 accept various operation inputs from an operator. In other words, the touch panel 22b is a display unit that displays various types of information and an operation input unit that receives an 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 (a volatile memory (main memory) 32 such as a RAM and a nonvolatile memory 33 such as an eMMC (embedded Multi Media Card)) constitute a computer system. The main system controller 20 implements various processing units in the main CPU 31 by executing predetermined software programs (hereinafter also simply referred to as programs) stored in the nonvolatile memory 33. 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 includes an AC-DC conversion unit (not shown), and uses the AC-DC conversion unit to convert power from the AC power supply (power after DC conversion) to each unit (main CPU 31) of the MFP 10. , Volatile memories 32 and 43, nonvolatile memories 33 and 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 power supply to each unit of the MFP 10. The power control IC 38 controls power supply to each unit of the MFP 10 in cooperation with the main CPU 31 and the sub CPU 41 (described below).

  The MFP 10 is also provided with a sub CPU 41. In the sleep state (power saving state) of the MFP 10, power supply to the main CPU 31 and the like is stopped, while power is supplied to the sub CPU 41, and the sub CPU 41 performs various operations (monitoring processing, determination processing, etc.). ) Can be performed. For example, the sub CPU 41 can control a communication operation with an external device. More specifically, the sub CPU 41 controls the main CPU 31 in response to an access (network access) via a communication network from another device (external device) in a power supply stop period and a return period (described later) with respect 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 implements various processing units (communication control unit and the like) by executing a predetermined program stored in the non-volatile memory 45 (flash ROM and the like) under its management. The communication control unit controls a communication operation with an 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, the sequence number, proxy reception data, and the like are stored in the SRAM 43 by the sub CPU 41 during the pause period and the return period of the main CPU 31. The SRAM 43 functions as a reception 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 (power supply stop period and return period of main CPU 31)>
When the MFP 10 transitions from the normal operation state Q1 to the power saving state (sleep state or the like) Q2, the main CPU 31 starts a snapshot data acquisition process. 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 for itself to the power supply unit 36. In response to this, the power supply unit 36 stops power supply to almost all the processing units including the main CPU 31 and the like, and causes the MFP 10 to transition to the power saving state Q2 (see FIG. 3).

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

  However, power is supplied to the sub CPU 41 and the SRAM 43 in the power saving state Q2. The sub CPU 41 can make a proxy response of the main CPU 31 to network access from other devices in 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). Is possible. In other words, the sub CPU 41 receives communication from each external device (transmission source device) in the proxy period (a period in which the processing authority is transferred from the main CPU 31 to the sub CPU 41 and executes processing on behalf), and It is possible to make a proxy response regarding communication. The power consumption of the sub CPU 41 etc. is less than the power consumption of the main CPU 31 etc. Therefore, by operating the sub CPU 41 (in place of the main CPU 31) in the power saving state Q2, it is possible to reduce the power consumption compared to operating the main CPU 31 in the power saving state Q2.

  In the substitution 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 present apparatus (MFP) 10 (10Z). A response process (proxy response process) for responding to the access on behalf of the main CPU 31 is executed. As will be described later, when a communication access to the MFP 10 is performed from an external device (80A, 80B, etc.), the sub CPU 41 acts as a proxy for the main CPU 31 for both the first type access and the second type access. Execute response processing (proxy response processing) that responds with. The present embodiment is different from the above-described comparative example in this point (a point in which the sub CPU 41 makes a proxy response to not only the first type of access but also the second type of access).

  Note that, 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 a single response to a single communication packet. Examples of the first type of access include queries related to name resolution. The second type of access is a type of communication access that requires responses 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 divided into a plurality of received packets and transmitted.

  More specifically, as shown in FIG. 5, in the substitution period T1 (a period including a power supply stop period T11 for the main CPU 31 and a subsequent return period T12), the sub CPU 41 performs the first type access. Proxy response to the second type of access (access requiring 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 as the comparative example described above (reply processing of the MAC address or the like) is executed. In short, the proxy response operation by the sub CPU 41 is executed. For example, when a name resolution protocol query (packets 701, 801, etc.) is received from another device (80A, 80B, etc.) as the first type of access, the MFP 10 (10Z) will receive the MAC address of its own device 10Z. Etc. are returned to the transmission source device (80A or 80B, etc.) to respond to the inquiry (proxy response).

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

  When the sub CPU 41 of the MFP 10 receives each communication packet related to communication access by TCP / IP in the proxy period T1 of the main CPU 31 of the MFP 10, the sub CPU 41 confirms the response to the transmission source device (80A or 80B, etc.) related to each communication packet. It responds (proxy response) to each communication packet by TCP / IP by returning (“ACK” signal).

  More specifically, first, when a communication packet (“SYN” signal) (101, 201, etc.) for establishing communication is transmitted from the transmission source device, the MFP 10Z (sub CPU 41) receives the received “SYN” signal. An acknowledgment response (“ACK” signal) is sent back to. Subsequently, when a plurality of data packets (communication packets indicating data contents) are sequentially transmitted from the transmission source device, the MFP 10Z (sub CPU 41) confirms an acknowledgment (“ACK” for the received plurality of data packets. ”Signal). As described above, the sub CPU 41 returns a confirmation response to the TCP / IP communication access (specifically, the plurality of packets).

  In this embodiment, the sub CPU 41 sequentially assigns a sequence number (sequential number) to each of a plurality of received packets related to the second type of access from each transmission source device. The sequence number does not need to start from number 1 (or number 0), but may start from an appropriate number. Further, the sequence number may be a number (a number uniquely assigned by the sub CPU 41) that is unrelated to the sequence number used in the main CPU before the main CPU shifts to the power saving state. The sequence number is a management sequence number for received packets, and is assigned and managed by the sub CPU 41. The sequence number is assigned and managed for each transmission source device and for each access.

  For example, consecutive numbers starting from “101” are sequentially given to received packets related to TCP / IP communication transmitted from the device 80A, and received packets related to TCP / IP communication transmitted from the device 80B. Thus, consecutive numbers starting with another number “201” are sequentially given. It should be noted that another 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 transmission source device and each access (type).

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

  For example, if a sequence number “101” is assigned to a communication packet 101 (“TCP / IP [SYN] A1”) from a certain transmission source device 80A, the reception time of the communication packet 101 is accordingly determined. “101” is stored in the SRAM 43 as the latest sequence number (latest information “latest sequence number” of a plurality of sequence numbers related to access from the transmission source device 80A).

  Thereafter, the sequence number “102” (a 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 transmission source device 80A. The In response to this, “102” is stored in the SRAM 43 as the latest sequence number (latest sequence number related to access from the transmission source device 80A) at the time of reception of the communication packet 102.

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

  Similarly, for the next communication packet 202 (“TCP / IP [data] B2”) from the other transmission source device 80B, the sequence number “202” (the immediately preceding “201” is incremented by 1). Value). In response to this, “202” is stored in the SRAM 43 as the latest sequence number (latest sequence number related to access from the transmission source device 80B) at the time of reception of 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, data received by the communication packet 102 and data received by the communication packet 202 are stored in the SRAM 43. The proxy reception data regarding 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 transferred 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.

  In this embodiment, the sub CPU 41 determines that the main CPU 31 should be restarted when it receives the second type of access for the first time in the proxy period T1. In FIG. 5, when a communication packet 101 (“TCP / IP [SYN] A1”) from a certain transmission 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 (return command for returning the main CPU 31 to the activated state) (also referred to as an activation request for the main CPU 31) to the main CPU 31 and the power supply unit 36. The power supply unit 36 resumes power supply to the main CPU 31, the main memory 32, and the like, and the main CPU 31 starts a 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 nonvolatile memory 33. The time required for the restart operation by the high-speed startup using the snapshot data is shorter than the time required for the normal restart operation without using the snapshot data (for example, about several tens of seconds).

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

<2-2. After completion of restart of the main CPU 31 (after the substitution period T1)>
Thereafter, when the main CPU 31 returns to the activated state, the main CPU 31 sends a return completion notification to the sub CPU 41. Upon receiving the return completion notification, the sub CPU 41 returns the proxy authority to the main CPU 31 (transfers authority to the main CPU 31). To do). The main CPU 31 again performs normal operations (including network communication operations).

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

  When the main CPU 31 returns to the restart 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 takes over the latest information (latest sequence number) regarding a plurality of sequence numbers given to the received packet in the second type access via the SRAM 43 to the restored main CPU.

  For example, the main CPU 31 receives the latest sequence number “102” from the sub CPU 41 via the SRAM 43 regarding the TCP / IP communication (“TCP / IP [data] Ai”) from the transmission source device 80A. Then, the main CPU 31 sets the sequence number “103” (a value obtained by incrementing the immediately preceding “102” by 1) for the next communication packet 103 (“TCP / IP [data] A3”) from the transmission source device 80A. Give. Further, “103” is stored in the main memory 32 as the latest sequence number at the time of receiving the communication packet 103 (latest sequence number related to access from the transmission source device 80A). The same reception process may be performed for the subsequent new communication packets 104, 105,.

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

  Further, 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 the TCP / IP communication. In other words, the correspondence between the received data relating to each packet and the sequence numbers assigned to the respective packets by the sub CPU 41 and the main CPU 31 is also used. Thereby, for example, correct whole data (print data or the like) is restored based on the data of each packet to which sequence numbers “102”, “103”,. At this time, 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. Accordingly, 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 proxy by the sub CPU 41 before returning.

  Similarly, the main CPU 31 restores correct data by rearranging the received data in the communication packets of the sequence numbers “202”, “203”,... In the original transmission order. At this time, 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 proxy by the sub CPU 41 before returning.

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

  In particular, during the power supply stop period and return period for the main CPU 31, the sub CPU 41 sends back an acknowledgment (ACK) as a proxy for the second type of access. Can immediately transmit the next packet without retrying. Accordingly, it is possible to avoid time-out determination and to appropriately proceed without stagnation of data transmission using a plurality of packets.

  Here, the 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.). May be. In addition, 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. Modified example>
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-described embodiment and the like, the sub CPU 41 individually responds to each of the plurality of received packets. However, the present invention is not limited to this, and the sub CPU 41 includes several received packets (for example, two received packets). ) May be collectively responded (confirmation response or the like).

  Further, in the above-described embodiment and the like, when the sub CPU 41 receives the second type of access during the proxy period T1, the sub CPU 41 receives a confirmation response (data has been normally received) from the transmission source device regarding the second type of access. ACK signal) is returned to respond to the second type of access (proxy response), but is not limited to this.

  For example, when the sub CPU 41 receives the second type of access during the power supply suspension period to the main CPU 31, for example, the sub CPU 41 issues a substantial standby request (wait command or the like) to the transmission source device related to the second type of access. You may make it respond (proxy response) with respect to the said 2nd type access by replying. In other words, the sub CPU 41 may perform a reply (response) to the transmission source device while suppressing data transmission from the transmission source device.

  Specifically, for example, the sub CPU 41 may transmit a reply indicating that the window size in TCP / IP communication has been changed to zero as a “wait command”. More specifically, as a response to the packet 101 (, 201, etc.) (see FIG. 5), “ACK that also indicates that the window size has been changed to zero” is sent from the MFP 10 to the device 80A (, 80B, etc.). It only has to be sent to.

  When the reply with the window size set to zero is transmitted to the transmission source device (80), the transmission destination device (MFP) receives data due to insufficient free space in the reception buffer memory of the transmission destination device. The fact that it cannot be received can be transmitted to the transmission source device (80). Thereby, data transmission from the transmission source device (80) can be suppressed.

  The transmission source device (80) that has received the reply that the window size is set to zero transmits a transmission request for a new window size to the MFP (transmission destination device) after waiting for a certain period.

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

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

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

  In such a case, in the proxy period T1, the transmission source device (80B, etc.) has received a “wait command” as a response to the packet transmission, and some reply (response) from the transmission destination device (MFP). ). Therefore, the transmission source device (80B or the like) does not perform timeout determination. After that, when the transmission / reception (request for transmission of a new window size, etc.) related to the wait 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 data from the external device may be performed by the main CPU 31 after the main CPU 31 is restored, for example.

10 MFP (image forming apparatus)
31 Main CPU
32 Main memory 41 Sub CPU
43 SRAM (Static RAM)
80A, 80B Source device (external device)
T1 substitution period T11 Power supply stop period T12 Return period

Claims (6)

An image forming apparatus,
A main CPU;
In a first period including a period in which the main CPU has a dormant state and a return period in the middle of the main CPU returning from the dormant state to the activated state, a specific operation is performed via a communication network from an external device. A sub CPU capable of proxy response on behalf of the main CPU for a specific type of access requiring a response to a plurality of received packets of a type of access;
With
The sub CPU is
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 main CPU is returned to the start state, the latest number related to the plurality of sequence numbers assigned to the plurality of received packets within the first period with respect to the specific type of access is taken over to the main CPU. An image forming apparatus. The image forming apparatus according to claim 1.
After the main CPU returns to the activated state, the main CPU gives a value incremented by one to the latest value of the sequence number taken over from the sub CPU to the next received packet in the specific type of access. An image forming apparatus that takes over the reception operation of the remaining received packets in the specific type of access. The image forming apparatus according to claim 1, wherein:
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 transmission source device of the plurality of received packets, thereby An image forming apparatus characterized in that a proxy response is made with respect to the received packet. 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 data received by the plurality of received packets in a reception buffer;
The main CPU obtains data stored in the reception buffer by the sub CPU when the main CPU returns to the activated state. 5. The image forming apparatus according to claim 1, wherein:
The image forming apparatus, wherein the sub CPU individually manages a sequence number of a received packet in the specific type of access from a plurality of different apparatuses with respect to each of the plurality of apparatuses. In the sub CPU built in the image forming apparatus,
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 dormant state and a return period in the middle of the main CPU returning from the dormant state to an activated 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. And steps to
b) The latest number related to the plurality of sequence numbers assigned to the plurality of received packets within the first period with respect to the specific type of access is sent to the main CPU after completion of returning the main CPU to the startup state. The steps to take over,
A program for running

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