JP4943783B2 - Time synchronization apparatus, time synchronization system, time synchronization method, and program - Google Patents

Description

  The present invention relates to a time synchronization device, a time synchronization system, a time synchronization method, and a program for synchronizing time when communicating with other devices.

  Some conventional communication systems have a management device (higher-level device) and a managed device (lower-level device) managed by the management device on a network. Examples of the prior art of such a communication system include the following.

  For example, as disclosed in Patent Document 1, by providing inside a firewall, communication between a management device that is a server provided outside the firewall and a managed device that is a number of clients provided inside the firewall is mediated. When the intermediary device receives a command from each managed device, transfers it to the management device, and accesses the management device, the management device can send a response to any of the commands transferred so far. In this case, there is a “mediation device, communication system, communication method, program, and recording medium” that receives the response and transfers the response to the transmission source of the command corresponding to the response.

  For example, as disclosed in Patent Document 2, when a CPU of an image forming apparatus that is a managed apparatus detects an unusable factor (down factor) within a preset downtime measurement period (predetermined period), the CPU cannot be used. The vendor measures the downtime (unusable time) when the device cannot be used due to the occurrence of a factor, and every time the measured time reaches one of the preset downtime notification thresholds, the vendor There is a "remote management system and its electronic device, control method when unusable factor occurs, and program" to notify the management device on the side.

For example, as Patent Document 3, a management device capable of communicating with a communication device (managed device) that uses a component storing a digital certificate receives a digital certificate together with a communication request from the communication device, and receives the digital certificate. If it is determined that it is necessary to renew the digital certificate for the component, the digital certificate for update is transmitted to the communication device, and the communication device updates the digital certificate for the component. Transfer device, authentication data transfer device, digital certificate setting system, authentication data setting system, communication device control method, digital certificate setting method, authentication data setting method, program, and recording medium ”.
JP 2005-316991 A JP 2005-100304 A JP 2005-318572 A

  However, in the conventional communication systems such as those described in Patent Documents 1 to 3, the time synchronization apparatus has a simple timing at which the time synchronization is performed or only at the time of activation. Therefore, the device itself did not detect that the time was actually abnormal, and time synchronization was not executed.

  The present invention has been made in view of the above circumstances, and not only periodically triggers (timing) to synchronize time with other devices, but also the device itself detects time abnormality and corrects the time. It is an object of the present invention to provide a time synchronization device, a time synchronization system, a time synchronization method, and a program capable of performing time correction at a more accurate and optimal timing by determining an opportunity that requires (synchronization). To do.

In order to achieve such an object, a first aspect of the present invention is a time synchronization apparatus having a function of synchronizing time with another apparatus when communicating with the other apparatus, and the time of the own apparatus is set. Time correction is required by the internal clock to be measured, the host device time acquisition unit that acquires the time of the host device that manages the device itself, the trigger detection unit that detects the trigger that requires time correction of the internal clock, and the trigger detection unit If such trigger is detected, as the time correction of the internal clock, possess and time correction means for correcting the time of the own device to the time of the host apparatus, a trigger detection unit is acquired by the upper apparatus time acquisition means The time when predetermined information is stored in the storage medium together with the time of the host device is detected as a trigger that requires time correction .

According to a second aspect of the present invention, there is provided a time synchronization system having the time synchronization apparatus according to the first aspect of the present invention .

According to a third aspect of the present invention, when a time synchronization device that measures the time of its own device using an internal clock communicates with another device, the time of the host device that manages the own device is acquired, and the other device Time synchronization method that synchronizes the time of the internal clock with the trigger detection step for detecting the trigger for the time correction of the internal clock, and when the trigger for the time correction is detected by the trigger detection step, the time of the internal clock as a correction, when the time of the device itself possess a time correction step of correcting the time of the host apparatus, a trigger detection step of storing predetermined information in a storage medium together with the time of the upper apparatus acquired from the host apparatus Detecting as a trigger that requires time correction .

According to a fourth aspect of the present invention, when a time synchronization device that measures the time of its own device using an internal clock communicates with another device, the time of the host device that manages the own device is acquired. Is a program that synchronizes the time of the internal clock and the time synchronization device detects the trigger that requires time correction of the internal clock, and the trigger that requires time correction is detected by the trigger detection process. In this case, as time correction of the internal clock, time correction processing for correcting the time of the own device to the time of the upper device is executed, and the trigger detection processing stores predetermined information together with the time of the upper device acquired from the upper device. The present invention is characterized in that it is a process of detecting when it is stored in a medium as an opportunity that requires time correction .

  According to the present invention, it is possible to perform time correction at a more accurate and optimal timing.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

As an embodiment of the present invention, a configuration of a time synchronization system (communication system) is shown in FIG.
As shown in FIG. 1, the time synchronization system of this embodiment includes an installation environment A and an installation environment B. In the installation environment A, the G / W device 1 (high-order device) that is a management device and the mediation that is a managed device that is connected to the G / W device 1 via the Internet 4 and is managed by the G / W device 1. Device 2 (lower device of G / W device 1 and higher device for image printing device 3), and image printing device 3 connected to this mediation device 2 via a LAN or the like (lower level of mediation device 2) Device). In the installation environment B, an image that is a managed device that is connected to the G / W device 1 (high-level device), which is a management device, and the G / W device 1 via the Internet 4 and is managed by the G / W device 1. Printing device 5 (subordinate device of G / W device 1). In the installation environment A, the intermediary device 2 and the image printing device 5 in the installation environment B are time synchronization devices of the present embodiment, respectively.

FIG. 2 shows a functional configuration of the time synchronization device (the mediation device 2 and the image printing device 5) of the present embodiment.
As shown in FIG. 2, the time synchronization apparatus of the present embodiment indicates the own apparatus (the time synchronization apparatus itself. The other apparatus is an apparatus that communicates with the time synchronization apparatus, and indicates an upper apparatus and a lower apparatus. ) Has an internal clock 11 that measures the current time (current date and time). In addition, it has a built-in battery 10 for maintaining the operation of the internal clock 11 when the apparatus is not turned on.

  As shown in FIG. 2, the time synchronizer according to the present embodiment has a monotonically increasing clock 17 for measuring the time without being affected by the device starting means 14 and the internal clock 11 for starting the own device, and measuring the monotonically increasing clock. Based on the result, it has a scheduler 15 that executes a preset schedule (for example, communication with other devices).

  As shown in FIG. 2, the time synchronization apparatus of the present embodiment includes a higher-level device communication unit 23 for communicating with a higher-level device and a lower-level device communication unit 25 for communicating with a lower-level device. Further, the electronic certificate for higher-level device communication 24 for use in communication with the higher-level device and the lower-level device communication electronic certificate 27 for use in communication with the lower level device are held. In these cases, when the host device time acquisition means 16 acquires the host device time from the host device, the authenticity of the host device time is protected by using mutual authentication and encrypted communication using an electronic certificate. At the same time, it functions as a security means for preventing falsification of the time of the host device. Therefore, since the legitimacy of the time information of the host device that is the basis of the time correction is maintained, it is possible to prevent falsification of the time information and spoofing of the host device. In addition, the time synchronization apparatus of the present embodiment includes an electronic certificate update unit 18 that updates these electronic certificates.

  As shown in FIG. 2, the time synchronization apparatus of the present embodiment has time information (hereinafter simply referred to as “time”) indicating the current time (current date and time) of the host device, measured by an internal clock of the host device. The high-order apparatus time acquisition means 16 is acquired.

  As shown in FIG. 2, the time synchronization apparatus of the present embodiment includes an input operation receiving unit 19 (time changing unit) that receives an input operation from a user and sets / changes the time and time zone of the internal clock 11. Further, the input operation accepting means 19 has a minimum accuracy of ± N (N: a predetermined number) of the accuracy of the internal clock 11 and the accuracy of the internal clock of the host device that manages the device itself. It is also possible to accept an input operation for setting up to twice as an allowable time error (allowable time error setting means). Therefore, since an allowable error range can be specified, the balance between the time correction frequency and the time accuracy can be adjusted.

  As shown in FIG. 2, the time synchronization apparatus according to the present embodiment is accessible by the own apparatus and includes a storage medium 20 for storing predetermined information (data, file, directory).

  As illustrated in FIG. 2, the time synchronization apparatus according to the present embodiment includes a comparison target time acquisition unit 21 that acquires a comparison target time. The comparison target time is time information to be compared with the time of the internal clock 11 by the time comparison unit 13 described later. As an example, the time input by the input operation means 19, the time included in the information stored in the storage medium 20, the expiration date of the electronic certificate 24 for upper device communication and 27 for lower device communication, received from another device Time (for example, time stamp of a packet, etc.), etc. are mentioned.

  As shown in FIG. 2, the time synchronization apparatus according to the present embodiment compares the time of the own apparatus measured by the internal clock 11 with the time of the upper apparatus acquired by the upper apparatus time acquisition means 16. 13 The time comparison unit 13 compares the time of the own device measured by the internal clock 11 with the predetermined comparison target time acquired by the comparison target time acquisition unit 21. In addition to the time comparison function for comparing the times as described above, the time comparison unit 13 also has a function of detecting a trigger (timing) that requires time correction (time synchronization) of the internal clock 11. That is, an opportunity that requires time correction of the internal clock 11 is detected based on the result of comparing the times and the event (processing) in the own device. In the present embodiment, the time comparison means 13 has an opportunity detection function, but may be provided separately. Details of this opportunity detection function will be described later.

  As shown in FIG. 2, the time synchronization apparatus according to the present embodiment displays the time of its own device measured by the internal clock 11 when the time comparison unit 13 detects a trigger that requires time correction. Time correction means 12 for correcting to the time of the host device acquired by the time acquisition means 16 is provided. This time correction means 12 measures the time required for the reception processing during the time inquiry communication with the host device managing the own device using the monotonically increasing clock 17 that is not affected by the internal clock, and the result of this measurement is obtained. As a time lag caused by the communication processing, time correction may be performed after adding to the time acquired from the host device. Thus, the time can be corrected more accurately by adding the time lag required for communication for acquiring the time of the host device.

  As shown in FIG. 2, the time synchronization apparatus of the present embodiment includes time abnormality notification means 22. The time abnormality notifying means 22 indicates that the time of the own apparatus is normal to the other apparatus when the time of the own apparatus is normal as a result of the time correction by the time correcting means 12 (or the other apparatus That the electronic certificate of the other device has expired (first time abnormality notification means). Therefore, by detecting and notifying that the time of the other device is abnormal or that the expiration date of the electronic certificate of the other device has expired, it is possible to inform the other device of the timing of time correction and certificate update, Further, by detecting and notifying that the clock of the other device is abnormal, it is possible to inform the other device of the timing for time correction.

  In addition, when the time of the internal clock 11 returns to the default as a result of the time correction by the time correction unit 12, the time abnormality notification unit 22 detects that the internal battery 10 is abnormal, and manages the device accordingly. (Second time abnormality notification means). Therefore, by detecting that the time of the device itself cannot be maintained, it is possible to detect an abnormality of the internal battery without a module for checking the remaining amount of the internal battery.

  In addition, the time abnormality notifying means 22 is used even when the time of the file or data stored in the storage device accessible by the own apparatus or the own apparatus is abnormal even after the time correction by the time correcting means 12. Then, the time abnormality of the file or data is notified to the host system that manages the own device (third time abnormality notification means). If the time of the file or data is abnormal, file / data deletion / update means (not shown) for deleting or updating the file or data is provided based on the importance of the file or data. May be. In this way, it is possible to maintain the correctness of files and data by detecting files and data that have already been created at the wrong time and responding according to the importance of each file.

  In addition, the time abnormality notifying unit 22 has the time of its own device after the time correction unit 12 corrects the time, and the electronic certificate held by the own device for performing encrypted communication with another device has expired. If this is the case, a function that requests the higher-level device that manages the device itself to issue a new electronic certificate by encrypted communication using a special electronic certificate (rescue certificate 26) that is not time-checked (rescue certificate 26). Electronic certificate issuing request means). Thus, by checking the validity period of the electronic certificate from the corrected result, it is possible to prevent the electronic certificate that has not expired from being updated. Further, it is possible to prevent interception of new electronic certificate issuance by encrypted communication.

  Further, the time abnormality notifying means 22 also has a function (response means) for responding to inquiries from lower devices managed by the own device, and after the time of the own device is corrected by the time correcting means 12, In response to an inquiry from a lower-level device, the time of its own device is returned. Therefore, it is possible to make the time transmitted to the lower device accurate.

  As shown in FIG. 2, the time synchronization apparatus according to the present embodiment is a special electronic certificate (rescue certificate) that is not time-checked to other apparatuses when an expired electronic certificate cannot be updated. 26) It has own device stop means 28 for notifying the stop of the own device by the encrypted communication according to 26) and stopping the own device after the notification. Further, as means for notifying the stop of the own apparatus (own apparatus stop notifying means), there are a stop screen display means 29 for displaying a message indicating that the own apparatus is stopped, and a stop LED lighting means 30 for turning on the LED. Therefore, in the case where it is not possible to operate normally even if the time of the own device is corrected correctly, notification to other devices related to the own device and display of stoppage by LED or screen in the own device By performing the above, it is possible to notify the surroundings and the user that the device is inoperable.

  As described above, the time synchronization apparatus according to the present embodiment is a time synchronization apparatus having a function of synchronizing time with another apparatus when communicating with another apparatus (higher-order apparatus or lower-order apparatus). Internal clock 11 that measures the time of its own device (time synchronization device itself), upper device time acquisition means 16 that acquires the time of the higher-level device that manages its own device, and triggers that require time correction of internal clock 11 are detected When the time comparison means 13 having an opportunity detection function and the opportunity detection function of the time comparison means 13 detect an opportunity that requires time correction, the time of the own device is set as the time of the host device as time correction of the internal clock 11. And a time correction means for correcting to a main structure.

  Here, “the trigger detection function of the time comparison unit 13”, which is a main feature of the present time synchronization apparatus, will be described in detail. As described above, the trigger detection function is a function that detects a trigger (timing) that requires time correction (time synchronization) of the internal clock 11. When the predetermined trigger described below is detected by this function, the time of the own device measured by the internal clock 11 is acquired by the host device time acquisition unit 16 by the time correction unit 12. It is corrected (synchronized) with the time of the host device.

  As a detection example 1, the time comparison function compares the time of the host device acquired by the host device time acquisition means 16 with the time of its own device measured by the internal clock 11, and the trigger detection function It is determined whether or not the difference is within a predetermined allowable time error range, and if the result of the determination is that the difference between the two times is not within the allowable time error range, it is detected as a trigger that requires time correction.

  Therefore, according to the detection example 1, since the time of the host device is synchronized when time correction is necessary, the time of the device can be kept correct.

  As a detection example 2, the trigger detection function uses a time at which time correction is required as a time when predetermined information (such as important information) is stored in the storage medium 20 together with the time of the host device acquired by the host device time acquisition unit 16. Detect.

  Therefore, according to the detection example 2, it is possible to ensure that the time of information stored in the storage medium 20 is correct.

  As a detection example 3, the time comparison function compares the expiration date of the electronic certificate held by the own device for performing encrypted communication with another device and the time of the own device measured by the internal clock, and detects the trigger. The function determines whether or not the time of its own device is within the validity period of the electronic certificate, and if the result of the determination is that the time of its own device is not within the validity period of the electronic certificate, Detected as an opportunity for correction.

  Therefore, according to the detection example 3, since the time when the current time of the own device is outside the range of the validity period of the electronic certificate is necessary as the time correction, the time when the own device is outside the validity period of the electronic certificate. Can be prevented from moving in.

  As detection example 4, the time comparison function is measured by the expiration date of the electronic certificate sent from the other device and the internal clock when the device performs encrypted communication with the other device using the electronic certificate. The trigger detection function compares the time of its own device and determines whether the time of its own device is within the validity period of the electronic certificate. When it is not within the range of the expiration date, it is detected as an opportunity that requires time correction.

  Therefore, according to the detection example 4, since the time when the current time of the own device is out of the validity period of the electronic certificate sent from the other device is an opportunity that requires time correction, the electronic certificate of the other device is used. Can guarantee and reject the certificate correctly.

  As a detection example 5, the time comparison function uses the time of the lower device included in the information sent from the lower device and the own device measured by the internal clock when communicating with the lower device managed by the own device. The trigger detection function determines the time of the lower device, and if the result of the determination is that the time of the lower device is later than the time of the own device, or is past the predetermined time Is detected as an opportunity that requires time correction.

  Therefore, according to the detection example 5, the result of comparing the current time of the own device and the time of the other device included in the information transmitted from the other device is used as a trigger for time correction. An abnormality in the time of another device can be detected.

  As a detection example 6, the time comparison function compares the time stamp of the packet sent from the other device with the time of the own device measured by the internal clock at the time of communication with the other device. It is determined whether the difference between the two times is within the range of the allowable time error, and if the result of the determination is that the difference between the two times is not within the range of the allowable time error, it is detected as a trigger that requires time correction. To do.

  Therefore, according to the detection example 6, since the result of comparing the current time of the own device and the time stamp of the communication packet with the other device is an opportunity for time correction, the detection examples 4 and 5 It is possible to detect an abnormality in the time of the own device or other device during communication that cannot be performed.

  As a detection example 7, the trigger detection function detects when a notification that the time of its own device is abnormal is received from another device as a trigger that requires time correction.

  Therefore, according to the detection example 7, the reception of the notification of the time abnormality from the other device is used as a trigger for the time correction, so that the time abnormality that cannot be detected by the device itself can be detected.

  As a detection example 8, the trigger detection function detects a fixed period measured by a timer with a monotonically increasing clock as a trigger that requires time correction.

  Therefore, according to the detection example 8, since there is an opportunity for periodic time correction that is not affected by the clock held by the apparatus, the time is periodically corrected, and a schedule based on the clock (for example, another apparatus) Communication) is not executed due to clock rewinding or the like (detection examples 4, 5, 6, etc.), there is a possibility that time adjustment will not occur indefinitely, but this can be covered.

  As detection example 9, the trigger detection function detects when the own apparatus is started as a trigger that requires time correction.

  Therefore, according to the detection example 9, when the power is turned off, the time information of the clock is maintained, the battery is dead, and the time is returned to the default, or when the power is originally turned off. When the time information is not held, the time of startup is used as a trigger for time correction, so that the time in the above case can be corrected correctly.

  As detection example 10, the trigger detection function detects when an operation for setting and changing the time and time zone of the internal clock is received by the input operation reception unit 19 as a trigger that requires time correction.

  Therefore, according to the tenth detection example, when the information related to the time of the internal clock 11 is changed by an input operation from the screen or the like, the time correction is used as an opportunity to correct the time. Can do.

  According to the detection example 11, the time comparison function compares the time stamp of the file and directory stored in the storage medium accessible to the own device with the time of the own device measured by the internal clock, and detects the trigger. The function determines the time stamp of the file and directory. As a result of the determination, if the time stamp of the file and directory is later than the time of its own device, or if it is past the predetermined time. Detected as an opportunity that requires time correction.

  Therefore, according to the detection example 11, since the time abnormality is detected from the result of comparing the current time of the own device and the time stamp of the file of the storage medium 20 and the time correction is triggered, each time the file is accessed Time information can be corrected.

  As a detection example 12, the time comparison function compares the time included in the content of data held by the own device with the time of the own device measured by the internal clock, and the trigger detection function is held by the own device. If the time included in the data content held by the own device is later than the time of the own device as a result of the determination, or a predetermined time A case where the time is earlier than the time is detected as an opportunity that requires time correction.

  Therefore, according to the detection example 12, the abnormality is detected from the comparison between the current time of the own device and the time in the data file held in the own device, and the time correction is triggered. The time can be corrected for each access.

  As a detection example 13, the trigger detection function detects when an inquiry from a lower-level device is received for the time of the own device as a trigger that requires time correction.

  Therefore, according to the detection example 13, when the time information is inquired from the lower device, the time correction is triggered, so the time information transmitted to the lower device can be made accurate.

  Each means and each function described above may be realized by either hardware or software. When implemented by software, a time synchronization program is read into the time synchronization apparatus of the present embodiment and controls the operation of the time synchronization apparatus. The time synchronization apparatus realizes the above-described means and functions by the control of the time synchronization program, and executes processing operations described below.

  Next, the basic processing operation of the time synchronization apparatus of this embodiment will be described with reference to FIG. In FIG. 4, acquisition of time information from the host device, correction of the time of the own device, and update of the electronic certificate will be described.

  Encrypted communication using the electronic certificate is performed on the host device (G / W device 1 in FIG. 1) (step S1 / YES), and it is determined whether the encrypted communication is successful (step S2).

  In step S2, when the encrypted communication is successful (step S2 / success), time information indicating the time of the host device measured by the internal clock of the host device is acquired from the host device (step S3). Then, the time measured by the internal clock 11 of the time synchronizer is compared with the time information acquired from the host device (step S4), and whether or not the difference between the two times is within a preset allowable range. Judgment is made (step S5). Here, if the difference is within the allowable range (step S5 / within range), the process proceeds to B without correcting the time of the internal clock 11 (see FIG. 3 for processing after B). If the difference is outside the permissible range (step S5 / out of range), as described in the detection example 1 above, this is detected as a trigger for time correction, and the time of the internal clock 11 is corrected to the time of the upper clock ( Step S6), proceed to C (see FIG. 3 for processing after C).

  If the encrypted communication fails in step S2 (step S2 / failure), it is determined whether or not the HTTP has failed (step S8). Here, when it is a failure of HTTP (step S8 / YES), it returns to step S1 and tries again. If the HTTP is successful (step S8 / NO), it is determined whether or not the electronic certificate (the upper apparatus communication electronic certificate 24 in FIG. 1) has expired (step S9).

  In step S9, if the validity period of the electronic certificate has not expired (step S9 / NO), it is determined whether or not it is worth retrying (step S10). If it is worth retrying (step S10 / YES), the process returns to step S1 to retry. If there is no value for retry (step S10 / NO), the process proceeds to D (see FIG. 3 for the process after D).

  In step S9, when the validity period of the electronic certificate has expired (step S9 / YES), the electronic certificate stored in the own device is deleted (step S11). Communication with the host device is performed using a “digital certificate with no expiration date” different from the deleted electronic certificate (step S12), and it is determined whether the communication is successful (step S13).

  If communication fails in step S13 (step S13 / failure), it is determined whether or not there is a retry value (step S14). If it is worth retrying (step S14 / YES), the process returns to step S12 to retry. If there is no value for retry (step S14 / NO), the process proceeds to D (see FIG. 3 for the process after D).

  In step S13, when communication is successful (step S13 / success), time information indicating the time of the host device measured by the host device's internal clock is acquired from the host device and measured by the internal clock 11 of the time synchronization device. The time thus obtained is compared with the time information acquired from the host device (step S15), and it is determined whether or not the difference between the two times is within a preset allowable range (step S16). Here, if the difference is within the allowable range (step S16 / within range), the host device is requested to issue a new electronic certificate (step S18). If the difference is outside the allowable range (step S16 / out of range), as described in the detection example 1 above, this is detected as a trigger for time correction, and the time of the internal clock 11 is corrected to the time of the upper clock ( In step S17), a higher-level device is requested to issue a new electronic certificate (step S18).

  Then, it is determined whether or not the host device has issued a new electronic certificate (step S19). When a new electronic certificate is not issued (step S19 / NO), the process proceeds to F (see FIG. 3 for the process after F). When a new electronic certificate is issued (step S19 / YES), the electronic certificate is updated to a newly issued one (step S20), and the process proceeds to E (see FIG. 3 for the processing after E).

  Next, the timing of time correction and the processing after time correction in the time synchronization apparatus of the present embodiment will be described with reference to the flows of FIGS.

  FIG. 3A shows a case where the time synchronization device is activated (detection example 9) as a trigger for time correction. In this case, after the time correction is detected, the flow of FIG. And when it comes to BE of FIG. 4, a normal operation | movement is started. When the process reaches F in FIG. 4, the other apparatus is notified of the stop of the own apparatus, and the own apparatus is stopped.

  FIG. 3B shows a case where a time correction is detected when a time abnormality such as a file is detected (detection examples 11 and 12). In this case, after the time correction is detected, the flow of FIG. When the process reaches B in FIG. 4, deletion / change / notification to other apparatuses is performed according to the importance of the file. When reaching C to E in FIG. 4, the normal operation is continued. When the process reaches F in FIG. 4, the other apparatus is notified of the stop of the own apparatus, and the own apparatus is stopped.

  FIG. 3C shows the timing of time correction when a time abnormality notification is received from another device (detection example 7) and when a time abnormality is detected during communication with another device (detection examples 5 and 6). This is the case. In these cases, after detecting the timing of time correction, the flow of FIG. When the process reaches B in FIG. 4, the abnormality of the other apparatus is detected and the time abnormality is notified to the other apparatus. When reaching C to E in FIG. 4, the normal operation is continued. When the process reaches F in FIG. 4, the other apparatus is notified of the stop of the own apparatus, and the own apparatus is stopped.

  FIG. 3A shows a periodical (detection example 8), a predetermined information storage (detection example 2), an electronic certificate expiration date check (detection examples 3 and 4), an input operation accepting means (input screen). And so on) (detection example 10), and when there is a time inquiry from a lower-level device (detection example 13). In these cases, after detecting the timing of time correction, the flow of FIG. And when it comes to BE of FIG. 4, normal operation | movement is continued. When the process reaches F in FIG. 4, the other apparatus is notified of the stop of the own apparatus, and the own apparatus is stopped.

  As mentioned above, although embodiment of this invention was described, it is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the summary.

It is a figure which shows the structural example of the time synchronizer of this invention, and another apparatus (a high-order apparatus and a low-order apparatus). It is a block diagram which shows the function structure of the time synchronizer of this invention. It is a flowchart which shows the basic operation | movement of the time synchronizer of this invention. It is a flowchart which shows the opportunity of time correction in the time synchronization apparatus of this invention, and the operation | movement after time correction, respectively.

Explanation of symbols

1 G / W device (host device)
2 Mediation device (time synchronization device)
3 Image printing equipment (lower device)
4 Internet 5 Image printing equipment (time synchronization device)
DESCRIPTION OF SYMBOLS 10 Built-in battery 11 Internal clock 12 Time correction means 13 Time comparison means 14 Apparatus start-up means 15 Scheduler 16 High-order apparatus time acquisition means 17 Monotonically increasing clock 18 Electronic certificate update means 19 Input operation reception means 20 Storage medium 21 Comparison target time acquisition means 22 Time Abnormal Notification Unit 23 Host Device Communication Unit 24 Host Device Communication Electronic Certificate 25 Subordinate Device Communication Unit 26 Rescue Certificate 27 Subordinate Device Communication Electronic Certificate 28 Own Device Stop Unit 29 Stop Screen Display Unit 30 Stop LED Lighting Unit

Claims (64)

A time synchronization device having a function of synchronizing time with another device when communicating with the other device,
An internal clock that measures the time of its own device,
Host device time acquisition means for acquiring the time of the host device that manages the host device;
Trigger detection means for detecting a trigger that requires time correction of the internal clock;
If the time correction is necessary trigger is detected by the trigger detection unit, wherein the time correction of the internal clock, have a, and time correction means for correcting the time of the time the upper apparatus of its own apparatus,
The opportunity detection means includes
A time synchronization apparatus that detects when the predetermined information is stored in a storage medium together with the time of the host apparatus acquired by the host apparatus time acquisition means as a trigger that requires the time correction . The opportunity detection means includes
The time of the host device acquired by the host device time acquisition means is compared with the time of the host device measured by the internal clock, and the difference between the two times is within a predetermined allowable time error range. Determine whether or not
2. The time synchronization apparatus according to claim 1, wherein, as a result of the determination, a case where the difference between the two times is not within the range of the allowable time error is detected as an opportunity that requires the time correction. The opportunity detection means includes
The self device compares the expiration date of the electronic certificate held for performing encrypted communication with the other device and the time of the self device measured by the internal clock, and the time of the self device is the electronic device. Determine if it is within the validity period of the certificate,
The time synchronization according to claim 1 or 2 , wherein, as a result of the determination, a case where the time of the own device is not within a range of an expiration date of the electronic certificate is detected as an opportunity for the time correction. apparatus. The opportunity detection means includes
When the device itself performs encrypted communication with the other device using the electronic certificate, the expiration date of the electronic certificate sent from the other device, and the time of the device measured by the internal clock To determine whether the time of the device is within the validity period of the electronic certificate,
A result of the determination, the case time of the self-device the not within the scope of the expiration date of the electronic certificate, any of claims 1 to 3, characterized in that said time correction is detected as a trigger required 1 The time synchronization device according to item. The opportunity detection means includes
When communicating with a lower device managed by the own device, the time of the lower device included in the information sent from the lower device is compared with the time of the own device measured by the internal clock. , Determine the time of the subordinate device,
As a result of the determination, a case where the time of the lower-order device is later than the time of the own device or a time earlier than a predetermined time is detected as an opportunity for the time correction. The time synchronizer according to any one of claims 1 to 4 , wherein The opportunity detection means includes
When communicating with the other device, the time stamp of the packet sent from the other device is compared with the time of the own device measured by the internal clock, and the difference between the two times is a predetermined allowable time error. Determine whether it is within range,
A result of the determination, wherein said case difference between the time is not within the range of the allowable time error, in any one of claims 1 to 5, characterized in that to detect a trigger requiring the time correction Time synchronizer. The opportunity detection means includes
Wherein when the notification time of the own device is abnormal is received from said another device, according to any one of claims 1 to 6, wherein the time correction is detected as triggered required Time synchronizer. Having a timer with a monotonically increasing clock not affected by the internal clock;
The opportunity detection means includes
Wherein the predetermined period each time it is measured by monotonically increasing clock by the timer, the time synchronization device according to any one of claims 1 to 7, characterized in that said time correction is detected as a trigger required. The opportunity detection means includes
The time synchronization apparatus according to any one of claims 1 to 8 , wherein the time when the own apparatus is activated is detected as an opportunity that requires the time correction. Having a time changing means for accepting a predetermined operation and changing the time of the internal clock;
The opportunity detection means includes
When the operation of changing the time and time zone of the internal clock is received at the time changing means, any one of claims 1 to 9, wherein the time correction is detected as triggered required The time synchronizer described in 1. The opportunity detection means includes
The time stamp of the file and the directory stored in the storage medium accessible to the device is compared with the time of the device measured by the internal clock to determine the time stamp of the file and the directory. ,
As a result of the determination, if the time stamp of the file and the directory is later than the time of the own device, or if it is past the predetermined time, the time correction is necessary. time synchronization device according to any one of claims 1 to 10, characterized in that to detect. The opportunity detection means includes
The time included in the content of data held by the own device is compared with the time of the own device measured by the internal clock, and the time contained in the content of data held by the own device is determined. Judgment
As a result of the determination, when the time included in the content of the data held by the own device is later than the time of the own device, or when the time is past the predetermined time, time synchronization device according to any one of claims 1 to 11, characterized in that a time correction detects triggered required. Response means for responding to an inquiry from a lower-level device managed by the device;
The opportunity detection means includes
The time when there is an inquiry from the lower device about the time of the own device is detected as an opportunity for the time correction,
The response means includes
After the time of the own apparatus is corrected by the time correction unit, in response to the inquiry from the subordinate apparatus, in any one of claims 1 to 12, characterized in that the response time of the own device The time synchronizer described. As a result of time correction by the time correction means, when the time of the own device is normal,
To the other device, time abnormality of the other device, or any of claims 1 to 13, characterized in that it comprises a first time abnormality notifying means for notifying an expired digital certificate of the other device The time synchronizer of Claim 1. As a result of time correction by the time correction means, when the time of the internal clock has returned to the default,
A second time abnormality notification means for detecting an abnormality of the internal battery for maintaining the internal clock when the power of the own device is not turned on and notifying the host device managing the own device to that effect time synchronization device according to any one of claims 1 14, characterized in that. The time correction means includes
The time required for reception processing during time inquiry communication to the host device that manages the device itself is measured using a monotonically increasing clock that is not affected by the internal clock, and the measurement result is used as a time lag caused by communication processing. , time synchronization device according to any one of claims 1 15, characterized in that said time correction after adding the time obtained from the host system. Of the accuracy of the internal clock and the accuracy of the internal clock of the host device that manages the device, up to ± N (N: a predetermined number) times the minimum digit of the coarser accuracy is used as the allowable time error. time synchronizer of claims 2 16, wherein it has an acceptable time error setting means capable of setting. When the time of the host device is acquired from the host device by the host device time acquisition means, the validity of the time of the host device is protected by using mutual authentication and encrypted communication using an electronic certificate. with time synchronization device according to any one of claims 1 to 17, characterized in that it comprises a security means to prevent tampering of time of the host system. Even after the time correction by the time correction means, the time of the own device falls under the expiration of an electronic certificate held by the own device for performing encrypted communication with the other device,
It has electronic certificate issuance request means for requesting the issuance of a new electronic certificate by encrypted communication using a special electronic certificate that is not time-checked to the host device that manages the device. The time synchronizer according to any one of claims 1 to 18 . After the time correction by the time correction means, if the time of the file or data stored in the storage medium accessible to the own device or the own device is abnormal,
Based on the importance of the file or the data, a file / data deletion / updating unit for deleting or updating the file or the data, or the time of the file or the data to the host system managing the device The time synchronization apparatus according to any one of claims 1 to 19 , further comprising third time abnormality notification means for notifying abnormality. If you are unable to renew an expired digital certificate,
Self-device stop notification means for notifying the stop of the self-device in encrypted communication using a special electronic certificate that is not time-checked to the other device;
After notifying by the own apparatus stop notification means, the own apparatus stopping means for stopping the own apparatus;
Own device stop notification means for notifying the stop of the own device;
Time synchronization device according to claim 1 in any one of 20, characterized in that it comprises a. A time synchronization system comprising the time synchronization device according to any one of claims 1 to 21 . When a time synchronization device that measures the time of its own device using an internal clock communicates with another device, it acquires the time of the host device that manages the device and synchronizes the time with the other device. A synchronization method,
Trigger detection step of detecting a trigger that requires time correction of the internal clock;
If the trigger detection trigger requiring the time correction in step is detected, the a time correction of the internal clock, have a, a time correction step of correcting the time of the time the upper apparatus of its own apparatus,
The opportunity detection step includes
A time synchronization method , wherein a time when predetermined information is stored in a storage medium together with the time of the host device acquired from the host device is detected as an opportunity for the time correction . The opportunity detection step includes
The time of the host device acquired from the host device is compared with the time of the host device measured by the internal clock, and it is determined whether or not the difference between both times is within a predetermined allowable time error range. And
24. The time synchronization method according to claim 23 , wherein when the difference between the two times is not within the range of the allowable time error as a result of the determination, the time synchronization method is detected as a trigger that requires the time correction. The opportunity detection step includes
The self device compares the expiration date of the electronic certificate held for performing encrypted communication with the other device and the time of the self device measured by the internal clock, and the time of the self device is the electronic device. Determine if it is within the validity period of the certificate,
The time synchronization according to claim 23 or 24 , wherein, as a result of the determination, a case where the time of the own device is not within a range of an expiration date of the electronic certificate is detected as an opportunity for the time correction. Method. The opportunity detection step includes
When the device itself performs encrypted communication with the other device using the electronic certificate, the expiration date of the electronic certificate sent from the other device, and the time of the device measured by the internal clock To determine whether the time of the device is within the validity period of the electronic certificate,
26. Any one of claims 23 to 25 , wherein, as a result of the determination, a case where the time of the self-apparatus is not within the validity period of the electronic certificate is detected as an opportunity for the time correction. The time synchronization method according to item. The opportunity detection step includes
When communicating with the lower device managed by the own device, the time of the lower device included in the information sent from the lower device is compared with the time of the own device measured by the internal clock, Determining the time of the subordinate device;
As a result of the determination, a case where the time of the lower-order device is later than the time of the own device or a time earlier than a predetermined time is detected as an opportunity for the time correction. The time synchronization method according to any one of claims 23 to 26 , wherein: The opportunity detection step includes
When communicating with the other device, the time stamp of the packet sent from the other device is compared with the time of the own device measured by the internal clock, and the difference between the two times is a predetermined allowable time error. Determine whether it is within range,
28. The case according to any one of claims 23 to 27 , wherein, as a result of the determination, a case where the difference between the two times is not within the range of the allowable time error is detected as a trigger that requires the time correction. Time synchronization method. The opportunity detection step includes
29. The time according to any one of claims 23 to 28 , wherein a time when the time correction is necessary is detected when a notification that the time of the own device is abnormal is received from the other device. Time synchronization method. The opportunity detection step includes
Wherein the predetermined period each time by monotonically increasing clock is not affected by the internal clock is measured by the timer, according to any one of claims 23 to 29, characterized in that to detect a trigger requiring the time correction Time synchronization method. The opportunity detection step includes
The time synchronization method according to any one of claims 23 to 30 , wherein the time when the device starts is detected as an opportunity that requires the time correction. The opportunity detection step includes
Wherein when having received the operation of changing the time and time zone of the internal clock, the time synchronization method according to any one of claims 23 31, characterized in that said time correction is detected as a trigger required. The opportunity detection step includes
The time stamp of the file and the directory stored in the storage medium accessible to the device is compared with the time of the device measured by the internal clock to determine the time stamp of the file and the directory. ,
As a result of the determination, if the time stamp of the file and the directory is later than the time of the own device, or if it is past the predetermined time, the time correction is necessary. The time synchronization method according to any one of claims 23 to 32 , wherein the time synchronization method is detected. The opportunity detection step includes
The time included in the content of data held by the own device is compared with the time of the own device measured by the internal clock, and the time contained in the content of data held by the own device is determined. Judgment
As a result of the determination, when the time included in the content of the data held by the own device is later than the time of the own device, or when the time is past the predetermined time, 34. The time synchronization method according to claim 23, wherein the time synchronization method is detected as an opportunity that requires time correction. The opportunity detection step includes
The time when there is an inquiry from the lower device about the time of the own device is detected as an opportunity for the time correction,
After the time of the own apparatus is corrected by the time correction step, to the inquiry from the subordinate apparatus, one of claims 23 34, characterized in that it has a response step for responding the time of the own device The time synchronization method according to claim 1. As a result of time correction by the time correction step, if the time of the device itself is normal,
To the other device, the time of another apparatus abnormalities, or one of claims 23, characterized in that it comprises a first time abnormality notification step of notifying an expired digital certificate of the other device 35 The time synchronization method according to claim 1. As a result of time correction by the time correction step, when the time of the internal clock has returned to the default,
A second time abnormality notification step of detecting an abnormality of the internal battery for maintaining the internal clock when the power of the own device is not turned on and notifying the host device that manages the own device to that effect The time synchronization method according to any one of claims 23 to 36 , wherein: The time correction step includes
The time required for reception processing during time inquiry communication to the host device that manages the device itself is measured using a monotonically increasing clock that is not affected by the internal clock, and the measurement result is used as a time lag caused by communication processing. time synchronization method according to claim 23 in any one of 37, wherein: performing the time correction after adding the time obtained from the host system. Of the accuracy of the internal clock and the accuracy of the internal clock of the host device that manages the device, up to ± N (N: a predetermined number) times the minimum digit of the coarser accuracy is used as the allowable time error. The time synchronization method according to any one of claims 23 to 38, further comprising an allowable time error setting step that can be set. When acquiring the time of the host device from the host device, the authenticity of the time of the host device is protected by using mutual authentication and encrypted communication using an electronic certificate, and the time of the host device time synchronization method according to any one of claims 23 to 39, characterized in that it comprises a security step to prevent tampering. Even after the time correction is performed by the time correction step, the time of the own device corresponds to the expiration of the electronic certificate held by the own device for performing encrypted communication with the other device,
An electronic certificate issuance requesting step for requesting issuance of a new electronic certificate by encrypted communication using a special electronic certificate that is not time-checked to the host device that manages the self-device. The time synchronization method according to any one of claims 23 to 40 . Even after the time correction is performed by the time correction step, if the time of the file or data stored in the storage medium accessible by the own device or the own device is abnormal,
Based on the importance of the file or the data, a file / data deletion / updating step for deleting or updating the file or the data, or the time of the file or the data with respect to a host system managing the device The time synchronization method according to any one of claims 23 to 41 , further comprising a third time abnormality notification step of notifying abnormality. If you are unable to renew an expired digital certificate,
A self-device stop notification step of notifying the stop of the self-device in encrypted communication using a special electronic certificate that is not time-checked to the other device;
After notifying by the own device stop notification step, the own device stop step of stopping the own device;
The own device stop notification step for notifying the stop of the own device;
43. The time synchronization method according to any one of claims 23 to 42 , comprising: When a time synchronization device that measures the time of its own device using an internal clock communicates with another device, it obtains the time of the host device that manages the device and synchronizes the time with the other device. A program for
In the time synchronization device,
Trigger detection processing for detecting a trigger that requires time correction of the internal clock;
When an opportunity requiring the time correction is detected by the trigger detection process, a time correction process for correcting the time of the own apparatus to the time of the host apparatus is performed as the time correction of the internal clock ,
The trigger detection process is
A program that is a process of detecting when the predetermined information is stored in a storage medium together with the time of the host device acquired from the host device as a trigger that requires the time correction . The trigger detection process is
The time of the host device acquired from the host device is compared with the time of the host device measured by the internal clock, and it is determined whether or not the difference between both times is within a predetermined allowable time error range. And
45. The program according to claim 44, which is a process of detecting, as a result of the determination, a case in which the difference between the two times is not within the range of the allowable time error as a trigger that requires the time correction. The trigger detection process is
The self device compares the expiration date of the electronic certificate held for performing encrypted communication with the other device and the time of the self device measured by the internal clock, and the time of the self device is the electronic device. Determine if it is within the validity period of the certificate,
46. The processing according to claim 44 or 45 , wherein as a result of the determination, the time of the device itself is not within the validity period of the electronic certificate, and is a process of detecting the time correction as an opportunity. Program. The trigger detection process is
When the device itself performs encrypted communication with the other device using the electronic certificate, the expiration date of the electronic certificate sent from the other device, and the time of the device measured by the internal clock To determine whether the time of the device is within the validity period of the electronic certificate,
The process according to any one of claims 44 to 46 , characterized in that, as a result of the determination, when the time of the self-apparatus is not within the validity period of the electronic certificate, the process detects the time correction as an opportunity. The program according to any one of the above items. The trigger detection process is
When communicating with a lower device managed by the own device, the time of the lower device included in the information sent from the lower device is compared with the time of the own device measured by the internal clock. , Determine the time of the subordinate device,
As a result of the determination, processing for detecting when the time of the lower device is in the future than the time of the own device, or when it is in the past of a predetermined time, as an opportunity for the time correction. The program according to any one of claims 44 to 47 , wherein: The trigger detection process is
When communicating with the other device, the time stamp of the packet sent from the other device is compared with the time of the own device measured by the internal clock, and the difference between the two times is a predetermined allowable time error. Determine whether it is within range,
The process according to any one of claims 44 to 48 , which is a process of detecting when the time correction is necessary when a difference between the two times is not within the range of the allowable time error as a result of the determination. The program described in the section. The trigger detection process is
50. The process according to any one of claims 44 to 49 , wherein the process detects a time when the time correction is necessary when a notification that the time of the own device is abnormal is received from the other device. The program described in. The trigger detection process is
Certain period each time measured by the internal clock timer according monotonically increasing clock unaffected by, any one of 50 claims 44, characterized in that the process of detecting as trigger requiring the time correction The program described in. The trigger detection process is
52. The program according to any one of claims 44 to 51 , wherein the program is a process of detecting when the device is activated as an opportunity that requires the time correction. The trigger detection process is
53. The program according to any one of claims 44 to 52 , which is a process of detecting when an operation of changing the time and time zone of the internal clock is received as an opportunity that requires the time correction. . The trigger detection process is
The time stamp of the file and the directory stored in the storage medium accessible to the device is compared with the time of the device measured by the internal clock to determine the time stamp of the file and the directory. ,
As a result of the determination, if the time stamp of the file and the directory is later than the time of the own device, or if it is past the predetermined time, the time correction is necessary. The program according to any one of claims 44 to 53 , wherein the program is a detection process. The trigger detection process is
The time included in the content of data held by the own device is compared with the time of the own device measured by the internal clock, and the time contained in the content of data held by the own device is determined. Judgment
As a result of the determination, when the time included in the content of the data held by the own device is later than the time of the own device, or when the time is past the predetermined time, 55. The program according to any one of claims 44 to 54 , wherein the program is a process for detecting a timing that requires time correction. The trigger detection process is
When there is an inquiry from the lower-level device about the time of the own device, the detection process is triggered by the need for the time correction,
In the time synchronization device,
After the time of the own apparatus is corrected by the time correction processing, in response to the inquiry from the subordinate apparatus, the claims 44, characterized in that to perform the response process for responding the time of its own device 55 for The program according to any one of the above items. As a result of time correction by the time correction process, when the time of the device itself is normal,
In the time synchronization device,
To the other device, time abnormality of the other device, or from claim 44, characterized in that to execute the first time abnormality notification processing of notifying an expired digital certificate of the other device 56 The program according to any one of the above items. As a result of time correction by the time correction process, when the time of the internal clock has returned to the default,
In the time synchronization device,
When the self-device is not powered on, it is detected as an abnormality in the built-in battery for maintaining the internal clock, and a second time abnormality notification process for notifying the host device that manages the self-device is performed. The program according to any one of claims 44 to 57 , wherein the program is executed. The time correction process is:
The time required for reception processing during time inquiry communication to the host device that manages the device itself is measured using a monotonically increasing clock that is not affected by the internal clock, and the measurement result is used as a time lag caused by communication processing. The program according to any one of claims 44 to 58 , wherein the time correction is performed in addition to the time acquired from the host device. In the time synchronization device,
Of the accuracy of the internal clock and the accuracy of the internal clock of the host device that manages the device, up to ± N (N: a predetermined number) times the minimum digit of the coarser accuracy is used as the allowable time error. The program according to any one of claims 44 to 59, wherein an allowable time error setting process that can be set is executed. In the time synchronization device,
When acquiring the time of the host device from the host device, the authenticity of the time of the host device is protected by using mutual authentication and encrypted communication using an electronic certificate, and the time of the host device The program according to any one of claims 44 to 60 , wherein security processing for preventing falsification of the program is executed. Even after the time correction is performed by the time correction process, the time of the own device corresponds to the expiration of the electronic certificate held by the own device for performing encrypted communication with the other device,
In the time synchronization device,
A higher-level device that manages the device itself is caused to execute an electronic certificate issuance request process for requesting the issuance of a new electronic certificate by encrypted communication using a special electronic certificate that is not time-checked. The program according to any one of claims 44 to 61 . Even when the time correction is performed by the time correction process, when the time of the file or data stored in the storage medium accessible by the own device or the own device is abnormal,
In the time synchronization device,
Based on the importance of the file or the data, a file / data deletion / updating process for deleting or updating the file or the data, or the time of the file or the data with respect to a host system managing the device The program according to any one of claims 44 to 62, wherein a third time abnormality notification process for notifying abnormality is executed. If you are unable to renew an expired digital certificate,
In the time synchronization device,
Self-device stop notification processing for notifying the stop of the self-device in encrypted communication using a special electronic certificate that is not time-checked to the other device;
After notifying by the own device stop notification process, the own device stop process for stopping the own device;
Own device stop notification processing for notifying the stop of the own device;
Program according to any one of claims 44 63, characterized in that for the execution.

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