JP2010063037A - Data transfer system, data receiver, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transfer system capable of restarting data transfer when reconnected after disconnection is detected. <P>SOLUTION: The data transfer system includes a data transmitter having an identifier, and a data receiver. The date receiver includes a communication control means for acquiring an identifier from an external apparatus, and a data reception control means comparing an identifier acquired from the external apparatus of which connection is detected after disconnection with an identifier acquired from the data transmitter before disconnection when disconnection from the data transmitter is detected. When both are coincident, the control means determines the external apparatus to be a data transmitter and sends a data transmission restart request to the data transmitter. Further, the data transmitter includes a data reception control means for transmitting a data transmission restart request to the data transmitter. The data transmitter includes a communication control means and a data transmission control means which interrupts data transmission and then restarts data transmission when receiving the data transmission restart request from the data receiver. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a data transfer technique, and more particularly to a data transfer system, a data receiving apparatus, and an image forming apparatus capable of resuming data transfer when reconnection is detected after detecting disconnection during data transfer.

In a data transfer system including a data transmission device that transmits data and a data reception device that receives data, an error that occurs on the communication path is detected, and error correction or data retransmission is performed. ing. For example, Patent Document 1 describes that when a scanner device is used as a data transmission device and a printer is used as a data reception device, the occurrence of a reception error is detected using a checksum. It is described that a printer that has detected a reception error due to a checksum transmits a reading instruction to the scanner device again.
JP 2003-60819 A

  As described in Patent Document 1, an error that occurs on a communication path is detected, and the error is automatically handled. However, the countermeasure after reconnection when the communication cable is disconnected or the communication path is disconnected due to the influence of a surge voltage or the like is not considered. That is, when the connection is reestablished after the disconnection, the data transfer is not automatically resumed, and the user must again instruct the data transfer. For example, when data is transferred from the scanner device to the printer, the user needs to start again after reading the original with the scanner device after reconnection.

  The present invention has been made in view of such a situation. A data transfer system, a data receiving apparatus, and an image forming apparatus capable of resuming data transfer when reconnected after detecting disconnection during data transfer are provided. The purpose is to provide.

  In order to solve the above-described problem, a data transfer system according to the first aspect of the present invention has a unique identifier, data transmission device that transmits data, and data that is connected to the data transmission device and receives data A data transfer system including a receiving device, wherein the data receiving device detects connection and disconnection with an external device that communicates with the same protocol as the data transmitting device, and the external device is connected When the communication control means for acquiring a unique identifier from the connected external device is detected and disconnection of the data transmission device is detected during data reception from the data transmission device from which the connection is detected, The unique identifier obtained from the external device whose connection is detected after disconnection is compared with the unique identifier obtained from the data transmission device related to the data reception, and both are compared. A data reception control means for determining that the external device is the data transmission device and transmitting a data transmission resumption request to the data transmission device, the data transmission device comprising: Communication control means for detecting the disconnection of the data, and when disconnection of the data receiving device is detected during data transmission to the data receiving device, the data transmission is interrupted, and then the data And a data transmission control means for resuming the data transmission when the data transmission resumption request is received from the receiving device.

  According to the present invention, when disconnection of the connection with the data transmission device is detected during data reception from the data transmission device from which the connection is detected, the external device from which the connection is detected after the disconnection is detected. The acquired unique identifier is compared with the unique identifier acquired from the data transmission device related to the data reception, and when both match, it is determined that the external device is the data transmission device, and data transmission is performed. A restart request is transmitted to the data transmission device, and when the data transmission device receives the data transmission restart request from the data reception device, the data transmission is resumed, and thus a disconnection during data transfer is detected. Later, data transfer can be automatically resumed when reconnected.

  Here, the data transmission control means of the data transmission device determines whether or not the data to be transmitted is stored when the data transmission restart request is received, and determines that the data to be transmitted is not stored. When this happens, it is possible to notify the data receiving device that it cannot be resumed.

  In order to solve the above problem, a data receiving apparatus according to a second aspect of the present invention is a data receiving apparatus that has a unique identifier and is connected to a data transmitting apparatus that transmits data to receive the data. Communication control that detects connection and disconnection of an external device that communicates with the same protocol as the data transmission device, and acquires a unique identifier from the connected external device when it detects that the external device is connected Means, and when a disconnection of the data transmission device is detected during data reception from the data transmission device from which the connection has been detected, a unique identifier obtained from the external device from which the connection has been detected after the disconnection, and The unique identifier obtained from the data transmission device related to data reception is compared, and if both match, it is determined that the external device is the data transmission device, and the data transmission Characterized in that it comprises a data receiving control means for transmitting a restart request to the data transmission device.

  In order to solve the above problem, an image forming apparatus according to a third aspect of the present invention has a unique identifier and is connected to a scanner apparatus that transmits read image data to receive the image data. And detecting a connection to and disconnection from an external device that communicates using the same protocol as the scanner device, and obtaining a unique identifier from the connected external device when detecting that the external device is connected. A communication controller and a unique identifier obtained from the external device from which the connection is detected after disconnection when the disconnection from the scanner device is detected during image data reception from the scanner device from which the connection has been detected; A unique identifier acquired from the scanner device is compared, and if both match, it is determined that the external device is the scanner device, and a data transmission restart request is made. Characterized in that it comprises a data reception control means for transmitting to the scanner device.

  According to the present invention, there is provided a data transfer system, a data receiving apparatus, and an image forming apparatus capable of resuming data transfer when reconnection is detected after detecting disconnection during data transfer.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a hardware configuration of the data transfer system according to the present embodiment. In the present embodiment, a case where a data transfer system is configured by the scanner unit 50 that functions as a data transmission device and the image forming apparatus 100 that functions as a data reception device will be described as an example. However, the present invention is not limited to the example of this figure. As the data transmission device, any external device that transmits data to a host device such as a media reading device or a storage device can be used. In addition, an information processing apparatus that receives data as a host apparatus such as a personal computer can be used as the data receiving apparatus.

  In this figure, a scanner unit 50 includes a microcomputer 51, a ROM 52, a RAM 53, an image reading engine 54, and a USB device I / F 55. Image data read by the image reading engine 54 is externally connected via the USB device I / F 55. It has a function to output to. The scanner unit 50 has a serial number that is an individual identifier. By referring to this serial number, the individual scanner unit 50 can be identified. The serial number is recorded on the ROM 52, for example.

  The microcomputer 51 performs image processing such as image reading control and shading correction in the scanner unit 50 by operating according to a program recorded in the ROM 52. The RAM 53 is used as a work area for the microcomputer 51. The image reading engine 54 includes a document table, a CCD as an image reading element, a light source, a carriage mechanism for moving the CCD with respect to the document, and the like. The USB device I / F 55 causes the scanner unit 50 to function as a USB device device, and performs processing for responding to a request from a USB host device connected via USB.

  As shown in FIG. 1, the image forming apparatus 100 includes a main board 10, an engine control board 20, an operation panel unit 30, and a print engine 40. The image forming apparatus 100 receives the image data transmitted from the scanner unit 50, and receives the received image. The print engine 40 has a function of forming an image based on the data.

  The main board 10 is a board that functions as a controller, and includes a CPU 11, a RAM 12, an HDD 13, and a USB host I / F 14. The CPU 11 operates in accordance with the firmware program F / W 13a recorded in the HDD 13, and controls data reception processing, image formation processing, and the like in the image forming apparatus 100. The RAM 12 is used as a work area for the CPU 11.

  The engine control board 20 is a board that controls image forming processing in the print engine 40, and includes a microcomputer 21, a RAM 22, and a ROM 23. The microcomputer 21 operates in accordance with a program recorded in the ROM 23, and performs halftone processing on image data acquired from the main board, conversion processing into a control command of the print engine 40, and the like. The RAM 22 is used as a work area for the microcomputer 21.

  The operation panel unit 30 includes a display device and operation buttons, and accepts an operation from a user or displays a menu. The print engine 40 includes a printing mechanism such as a paper supply / discharge mechanism and a print head, and forms an image on printing paper. The printing method is not limited, and a laser method, an ink jet method, or the like can be used.

  In the present embodiment, communication between the image forming apparatus 100 and the scanner unit 50 is performed using a USB. However, the present invention can use not only USB but also IEEE1394, SCSI and other communication methods. Also, it can be applied regardless of wired or wireless. In particular, the present invention can be effectively applied to wireless communication that is likely to be disconnected depending on the communication environment.

  FIG. 2 is a block diagram showing a functional configuration of the main board 10 and the scanner unit 50 in the data transfer system having the above configuration. This figure extracts the characteristic part of this embodiment.

  As shown in the figure, a USB host side communication control unit 110, a data reception control unit 120, and a reception data storage unit 130 are formed on the main board 10. These functional units are formed on the main substrate 10 by the CPU 11, the RAM 12, the USB host I / F 14 and the like performing processing cooperatively or independently.

  The USB host side communication control unit 110 performs processing for communicating as a USB host to a USB device connected via USB. The USB host-side communication control unit 110 includes a connection monitoring unit 111 that detects that a USB device is connected and that the USB device is disconnected. The connection monitoring unit 111 detects, for example, that the USB device has been connected and that the USB device has been disconnected by monitoring the voltage of the data signal line of the USB connector provided in the USB host I / F 14. can do. The disconnection from the USB device can occur, for example, when the USB cable is disconnected during data transmission / reception, or when an abnormal voltage due to a lightning surge or the like occurs during data transmission / reception.

  When the connection with the USB device is detected, the USB host-side communication control unit 110 performs a connection sequence with the USB device. In the connection sequence, the characteristics and attributes of the connected USB device are acquired, and the serial number is acquired from the USB device.

  The data reception control unit 120 performs processing for receiving data transmitted from the scanner unit 50. At the time of data reception, a command for requesting data transmission is transmitted to the scanner unit 50. Further, when the connection with the scanner unit 50 is disconnected while data is being received from the scanner unit 50, the data reception control unit 120 determines whether or not the USB device whose connection has been detected thereafter is the same scanner unit 50. When it is determined that they are the same, a process for requesting to resume the data transmission interrupted by the disconnection is performed. Therefore, the data reception control unit 120 includes a serial number storage unit 121, a serial number comparison unit 122, and a transmission resumption request unit 123.

  The serial number storage unit 121 is a storage area for storing a serial number acquired from a USB device that is performing data transmission. Specifically, when data reception from the USB device is started, the serial number acquired in the connection sequence with the USB device is stored.

  When the disconnection of the connection with the scanner unit 50 is detected during the data reception from the scanner unit 50 in which the connection is detected, the serial number comparison unit 122 detects the serial number acquired from the USB device in which the connection is detected after the disconnection. The serial number acquired from the scanner unit 50 stored in the serial number storage unit 121 is compared to determine whether or not they match.

  When the serial number comparison unit 122 determines that both serial numbers match, the transmission resumption request unit 123 is the scanner unit 50 to which the newly detected USB device is connected before disconnection. And a data transmission restart request is transmitted to the scanner unit 50. At this time, only the data transmission resumption request may be transmitted, or the received data may be specified and the data transmission resumption request may be transmitted.

  The received data storage unit 130 is a storage area for storing data sent from the scanner unit 50. By referring to the received data storage unit 130, received data can be specified.

  As shown in FIG. 2, the scanner unit 50 includes a USB device side communication control unit 510, a data transmission control unit 520, a transmission data storage unit 530, and an image reading unit 540. These functional units are formed on the main board 10 by the microcomputer 51, the RAM 53, the USB device I / F 55, the image reading engine 54, and the like performing processing cooperatively or independently.

  The USB device-side communication control unit 510 performs processing for communicating as a USB device with a USB host connected via USB. The USB device-side communication control unit 510 includes a connection monitoring unit 511 that detects that the USB host is connected and that the USB device is disconnected. The connection monitoring unit 511 detects, for example, that the USB host is connected and the connection with the USB host is disconnected by monitoring the voltage of the VBUS of the USB connector provided in the USB device I / F 55. Can do.

  Further, the USB device side communication control unit 510 transmits a serial number 512 set in advance in response to a serial number acquisition request from the USB host side. For example, the serial number 512 is recorded in the ROM 52 before shipment.

  The data transmission control unit 520 performs processing for transmitting the image data read by the image reading unit 540 and stored in the transmission data storage unit 530 to the image forming apparatus 100. Further, when disconnection of the connection with the data receiving device is detected during data transmission to the image forming apparatus 100, the data transmission is interrupted. Thereafter, when a data transmission resumption request is received from the image forming apparatus 100, the data transmission is performed. Perform the process to resume. Therefore, the data transmission control unit 520 includes a command storage unit 521 and a resumability determination unit 522.

  The command storage unit 521 is a storage area for storing commands sent from the image forming apparatus 100 and data to be sent to the image forming apparatus 100. When the data transmission resumption request is received from the image forming apparatus 100, the resumability determination unit 522 determines whether the data to be transmitted is stored in the transmission data storage unit 530, and stores the data to be transmitted. If it is determined that there is no data transmission, the image forming apparatus 100 is notified that data transmission cannot be resumed.

  The transmission data storage unit 530 is an area for storing data read by the image reading unit 540 and transmitted to the main board 10. Data that has been transmitted is erased. The image reading unit 540 reads image data from a document and stores it in the transmission data storage unit 530 in units of pages.

  Next, data reception control of the main board 10 of the image forming apparatus 100 will be described with reference to the flowchart of FIG. This process is started when the connection monitoring unit 111 of the USB host side communication control unit 110 detects the connection of the scanner unit 50 (S101). For example, when the USB cable is connected to the scanner unit 50, or when the power of the scanner unit 50 is turned on with the USB cable connected, the connection monitoring unit 111 connects the scanner unit 50 to the scanner unit 50. It is detected that

  When the connection is detected, a connection sequence is performed. In this process, the USB host side communication control unit 110 sends a serial number acquisition request to the scanner unit 50, and in response, a serial number is received from the scanner unit 50. Obtain (S102). The acquired serial number is stored in the serial number storage unit 121. However, it may be stored in the serial number storage unit 121 after actual data reception (S104) is started.

  When the general connection sequence is completed, communication between the image forming apparatus 100 and the scanner unit 50 is established (S103), and the scanner unit 50 starts data transmission in response to a data transmission request from the main board 10. The main board 10 receives the transmitted data (S104). The received data is sequentially stored in the received data storage unit 130. It is assumed that the document placed on the document table is being read by the scanner unit 50 prior to data transmission. Further, it is assumed that the read original includes a plurality of pages, and image data is generated for each page.

  If disconnection with the scanner unit 50 is not detected during data reception (S105: No), data reception (S104) is continued until reception of all pages is completed (S106).

  On the other hand, when it is detected that the connection with the scanner unit 50 is disconnected during data reception (S105: Yes), the data transmission from the scanner unit 50 is interrupted. Then, before the predetermined time elapses (S108), it is determined whether or not a USB device connection is detected (S107). This is because, in general, when an unintended disconnection occurs, reconnection is performed immediately. For example, when the USB cable is disconnected due to carelessness or the like, it is immediately reconnected, and when it is disconnected due to a surge voltage, the connection itself is often recovered immediately. In consideration of such a situation, a time serving as a determination criterion is determined in advance. If the connection of the USB device is not detected within the predetermined time (S108: Yes), the process ends as a reception error (S109). However, the predetermined time may not be set.

  If the connection of the USB device is detected before the predetermined time has elapsed (S108: No) (S107: Yes), the connection sequence is performed, and the serial number is acquired from the USB device that has newly detected the connection in the process (S110). ). At the time of acquisition, this serial number is not stored in the serial number storage unit 121. When the connection sequence ends, communication with the USB device is established (S111).

  When communication with the USB device is established, the serial number comparison unit 122 compares the serial number stored in the serial number storage unit 121 with the serial number acquired from the USB device that has newly detected the connection, and both Is determined to match (S112). The serial number stored in the serial number storage unit 121 is a serial number acquired from the scanner unit 50 that is disconnected during data reception. For this reason, the fact that they match each other means that the USB device that has newly detected the connection is the scanner unit 50. On the other hand, if they do not match, it means that a USB device different from the scanner unit 50 is connected.

  Therefore, when the two match (S112: Yes), the transmission resumption request unit 123 transmits a data transmission resumption request to the scanner unit 50. Upon receiving the data transmission restart request, the scanner unit 50 determines whether the data transmission can be restarted and notifies the image forming apparatus 100 of the result, as will be described later. If the data transmission can be resumed as a result of this notification (S114: Yes), a process for resuming reception is performed (S115), and data reception is resumed (S104). Therefore, after detecting a disconnection during data transfer, the data transfer can be resumed when reconnected.

  The process for resuming the reception is, for example, deleting the data of the page being received from the received data storage unit 130 when the disconnection is detected in the middle of the page. Details will be described later.

  If the data transmission cannot be resumed as a result of the notification from the scanner unit 50 (S114: No), the process ends as a reception error (S116). In this case, it is necessary to read the original again with the scanner unit 50 and transmit the data again.

  On the other hand, as a result of comparing the serial number stored in the serial number storage unit 121 with the serial number acquired from the USB device that has newly detected connection, if the two do not match (S112: No), the scanner unit 50 Since another USB device is connected, communication processing with the newly connected USB device is performed separately (S117).

  If communication fails due to a timeout or the like during data reception from the scanner unit 50, communication with the scanner unit 50 remains established, so that a retry request is sent to the scanner unit 50 as before. Just send it.

  Next, data transmission control in the scanner unit 50 will be described with reference to FIG. Since the scanner unit 50 functions as a USB device, processing is basically performed in a form of responding to a request from the image forming apparatus 100 that is a USB host.

  That is, as shown in FIG. 4A, when a serial number acquisition request is received from the image forming apparatus 100 (S201), the serial number 512 is transmitted as a response to the image forming apparatus 100 (S202). As shown in FIG. 4B, when a data transmission request is received from the image forming apparatus 100 after reading a plurality of pages (S211), the data transmission request command is stored in the command storage unit 521 (S212). Then, transmission of the read data is started (S213). When data for one page is transmitted, the transmitted data is erased (S214), and data transmission (S213) and data erasure (S214) are repeated until data transmission for all pages is completed (S215: Yes).

  As shown in FIG. 4C, when the connection monitoring unit 511 detects that the connection with the image forming apparatus 100 is disconnected during data transmission (S221), the scanner unit 50 interrupts data transmission. (S222).

  Furthermore, as shown in FIG. 4D, when the scanner unit 50 receives a data transmission resumption request from the image forming apparatus 100 (S231), the scanner unit 50 determines whether data transmission can be resumed (S232). Here, the determination of whether or not to resume data transmission will be described with reference to FIG. FIG. 5 is a diagram showing the data transmission timing of the data transmission side, that is, the scanner unit 50, and the data reception side, that is, the data reception timing of the image forming apparatus 100. An example of reading is taken as an example.

  Assuming that a time lag of dt occurs between the time when the data read by the scanner unit 50 is transmitted and the image forming apparatus 100 receives the data and writes the data in the received data storage unit 130, for example, at the time t1, the scanner unit 50 Data output is completed and data writing is completed in the image forming apparatus 100 after dt. In this embodiment, the scanner unit 50 deletes the data when the data output is completed. Therefore, there is no guarantee that the first data will remain after time t1. However, the transmission data storage unit 530 may have a ring buffer structure so that the data may remain even after the data output is completed.

  In this situation, for example, it is assumed that the disconnection of the scanner unit 50 is detected at time ta during transmission of the second data. In this case, since the second data transmission has not been completed and the second data has not yet been erased, the image forming apparatus 100 can transmit the second data from the beginning. For this reason, it can be determined that data transmission can be resumed.

  At this time, since the command storage unit 521 stores a command before disconnection, refer to the command and information of a page being transmitted that has not been transmitted and is stored in the transmission data storage unit 530. By doing so, it is possible to specify the processing content to be performed after the data transmission is resumed. Specifically, it is possible to specify data contents to be transmitted, transmission conditions, and the like. Further, since the image forming apparatus 100 can detect whether or not the transmission of the page is completed, the data may be transmitted from the page next to the page for which the transmission has been completed.

  On the other hand, even when the disconnection is detected while the scanner unit 50 is transmitting the second data, the scanner unit 50 reads the third and fourth image data from the image reading engine 54 as long as the RAM 53 is free. Continue reading by. The scanner unit 50 is provided with a time-out for the time taken to transport one document by ADF (Auto Document Feeder), the time taken to send one data, the time taken to send / receive each command, etc. When the time-out occurs regardless of resumption, it is processed as an error that has occurred in the scanner unit 50, and the previous command and document data may also be erased. In this case, it is determined that the data transmission cannot be resumed. Data transmission is also possible when the data to be transmitted cannot be specified due to other circumstances, the data to be transmitted is erased, or the command to be executed or the command to be transmitted is not stored. It will be judged that resumption is impossible.

  Returning to the flowchart of FIG. 4D, when it is determined that the data transmission can be resumed (S233: Yes), the image forming apparatus 100 is notified that the data transmission can be resumed (S234). Transmission is resumed (S235). In resuming data transmission, it starts from transmission of a page for which data transmission has not been completed.

  On the other hand, when it is determined that the data transmission cannot be resumed (S233: No), the image forming apparatus 100 is notified that the data transmission cannot be resumed (S236).

  In the above example, for example, when disconnection is detected during the data transmission of the second sheet, as shown in FIG. 6A, after the data transmission is resumed, the second sheet starts from the beginning. I was trying to send data. In this case, in the image forming apparatus 100, in the reception restart process (S115), as shown in FIG. 6B, the received data is discarded halfway through the second sheet.

  On the other hand, it may be transmitted after the data received by the image forming apparatus 100. In this case, when the transmission resumption request unit 123 of the image forming apparatus 100 transmits a data transmission resumption request to the scanner unit 50, the received data storage unit 130 is referred to obtain the received data size, and the information is stored. The scanner unit 50 is notified. On the other hand, the scanner unit 50 may identify data to be transmitted after resuming data transmission based on the notified received data size and resume data transmission. In this case, the image forming apparatus 100 only needs to store the received data in the received data storage unit 130 in succession, and therefore, in the reception resuming process (S115), it is not necessary to discard the received data partway through the page. .

  As described above, according to the present embodiment, data transfer can be automatically resumed when a connection is disconnected after detecting a disconnection during data transfer.

  The present invention is not limited to disconnection during data transfer, but also disconnection during command transmission from the image forming apparatus 100 functioning as a data receiving apparatus to the scanner unit 50 functioning as a data transmitting apparatus, and a data receiving apparatus. The present invention can also be applied to disconnection during standby for communication with the scanner unit 50 functioning as a data transmission device of the image forming apparatus 100 functioning as.

  First, command transmission control to the scanner unit 50 of the main substrate 10 of the image forming apparatus 100 will be described with reference to the flowchart of FIG. The description overlapping with the data reception control shown in FIG. 3 will be simplified.

  This process is started when the connection monitoring unit 111 of the USB host side communication control unit 110 detects the connection of the scanner unit 50 (S301). When the connection is detected, a connection sequence is performed. In this process, the USB host side communication control unit 110 sends a serial number acquisition request to the scanner unit 50, and in response, a serial number is received from the scanner unit 50. Obtain (S302).

  When the general connection sequence is completed, communication between the image forming apparatus 100 and the scanner unit 50 is established (S303), and the main board 10 transmits a necessary command to the scanner unit 50 (S304). Here, the necessary command can be, for example, an initialization command, an image reading command, a data transmission request, or the like.

  If disconnection with the scanner unit 50 is not detected during command transmission (S305: No), the command continues until command transmission ends (S306: Yes). On the other hand, when it is detected that the connection with the scanner unit 50 is disconnected during command transmission (S305: Yes), the command transmission to the scanner unit 50 is interrupted (S307). Then, before the predetermined time elapses (S309), it is determined whether or not a USB device connection is detected (S308). If the connection of the USB device is not detected within the predetermined time (S309: Yes), the process ends as a command transmission error (S310).

  If the connection of the USB device is detected before the predetermined time has elapsed (S309: No) (S308: Yes), the connection sequence is performed, and the serial number is acquired from the USB device that has newly detected the connection in the process (S311). ). At the time of acquisition, this serial number is not stored in the serial number storage unit 121. When the connection sequence is completed, communication with the USB device is established (S312).

  When communication with the USB device is established, the serial number comparison unit 122 compares the serial number stored in the serial number storage unit 121 with the serial number acquired from the USB device that has newly detected the connection, and both Is determined to match (S313).

  If the two match (S313: Yes), it is determined whether or not the command transmission to the scanner unit 50 can be resumed (S314). This determination can be made, for example, by checking whether a command to be transmitted is stored. As a result, when the command transmission can be resumed (S114: Yes), processing necessary for resuming the command transmission to the scanner unit 50 is performed (S315), and the command transmission is resumed (S304). If the command transmission cannot be resumed (S314: No), the process ends as a command transmission error (S316).

  On the other hand, as a result of comparing the serial number stored in the serial number storage unit 121 with the serial number acquired from the USB device that has newly detected connection, if the two do not match (S313: No), the scanner unit 50 Since another USB device is connected, communication processing with the newly connected USB device is performed separately (S317).

  Next, communication standby control with the scanner unit 50 of the main substrate 10 of the image forming apparatus 100 will be described with reference to the flowchart of FIG. The description overlapping with the data reception control shown in FIG. 3 will be simplified.

  This process is started when the connection monitoring unit 111 of the USB host side communication control unit 110 detects the connection of the scanner unit 50 (S401). When the connection is detected, a connection sequence is performed. In this process, the USB host side communication control unit 110 sends a serial number acquisition request to the scanner unit 50, and in response, a serial number is received from the scanner unit 50. Obtain (S402).

  When the general connection sequence is completed, communication between the image forming apparatus 100 and the scanner unit 50 is established (S403), and the main board 10 enters a communication standby state with the scanner unit 50.

  If disconnection with the scanner unit 50 is not detected (S404: No), the communication standby state is continued. On the other hand, if it is detected that the connection with the scanner unit 50 has been disconnected during communication standby (S404: Yes), whether or not the connection of the USB device has been detected before the predetermined time has elapsed (S406). Is determined (S405). If the connection of the USB device is not detected within the predetermined time (S406: Yes), the process ends as a connection error (S407).

  If the connection of the USB device is detected before the predetermined time has elapsed (S406: No) (S405: Yes), the connection sequence is performed, and the serial number is acquired from the USB device that has newly detected the connection in the process (S408). ). At the time of acquisition, this serial number is not stored in the serial number storage unit 121. When the connection sequence is completed, communication with the USB device is established (S409).

  When communication with the USB device is established, the serial number comparison unit 122 compares the serial number stored in the serial number storage unit 121 with the serial number acquired from the USB device that has newly detected the connection, and both (S410).

  If the two match (S410: Yes), the communication standby state with the scanner unit 50 is again entered. On the other hand, if they do not match (S410: No), since a USB device different from the scanner unit 50 is connected, communication processing with the newly connected USB device is performed separately (S411).

It is a block diagram which shows the hardware constitutions of the data transfer system which concerns on this embodiment. It is a block diagram which shows the function structure of the main board | substrate and scanner unit in a data transfer system. 6 is a flowchart illustrating data reception control of a main board of the image forming apparatus. It is a flowchart explaining the data transmission control in a scanner unit. It is a figure explaining the decision | availability judgment of data transmission resumption. It is a figure explaining the data transmitted after resumption of data transmission. 6 is a flowchart illustrating command transmission control of the main board of the image forming apparatus. 6 is a flowchart illustrating communication standby control of the main board of the image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Main board, 11 ... CPU, 12 ... RAM, 13 ... HDD, 14 ... USB host I / F, 20 ... Engine control board, 21 ... Microcomputer, 22 ... RAM, 23 ... ROM, 30 ... Operation panel unit, 40 ... Print engine, 50 ... Scanner unit, 51 ... Microcomputer, 52 ... ROM, 53 ... RAM, 54 ... Image reading engine, 55 ... USB device I / F, 100 ... Image forming apparatus, 110 ... USB host side communication control unit, DESCRIPTION OF SYMBOLS 111 ... Connection monitoring part, 120 ... Data reception control part, 121 ... Serial number storage part, 122 ... Serial number comparison part, 123 ... Transmission resumption request part, 130 ... Reception data storage part, 510 ... USB device side communication control part, 511: Connection monitoring unit, 512 ... Serial number, 520 ... Data transmission control unit, 521 ... Command storage unit, 522 ... Re Determination unit, 530 ... transmission data storage unit, 540 ... image reading section

Claims (6)

A data transfer system having a unique identifier and including a data transmission device that transmits data and a data reception device that is connected to the data transmission device and receives data,
The data receiving device is:
Communication control means for detecting connection to and disconnection from an external device that communicates using the same protocol as the data transmission device, and acquiring a unique identifier from the connected external device when detecting that the external device is connected When,
When disconnection of the data transmission device is detected during data reception from the data transmission device from which the connection has been detected, the unique identifier obtained from the external device from which the connection has been detected after disconnection, and the Data reception that compares a unique identifier acquired from the data transmission device and determines that the external device is the data transmission device when both match, and transmits a data transmission resume request to the data transmission device Control means,
The data transmission device includes:
Communication control means for detecting that the connection with the data receiving device has been disconnected;
When disconnection of the data receiving device is detected during data transmission to the data receiving device, the data transmission is interrupted, and then when the data transmission restart request is received from the data receiving device, the data transmission Data transmission control means for resuming
A data transfer system. The data transfer system according to claim 1,
The data transmission control means of the data transmission device comprises:
When the data transmission restart request is received, it is determined whether or not the data to be transmitted is stored, and when it is determined that the data to be transmitted is not stored, the data receiving device cannot be restarted. A data transfer system characterized by notifying. A data receiving device having a unique identifier and receiving the data by connecting to a data transmitting device for transmitting data,
Communication control means for detecting connection to and disconnection from an external device that communicates using the same protocol as the data transmission device, and acquiring a unique identifier from the connected external device when detecting that the external device is connected When,
When disconnection of the data transmission device is detected during data reception from the data transmission device from which the connection has been detected, the unique identifier obtained from the external device from which the connection has been detected after disconnection, and the Data reception that compares a unique identifier acquired from the data transmission device and determines that the external device is the data transmission device when both match, and transmits a data transmission resume request to the data transmission device A data receiving apparatus comprising: a control unit. A data receiving device having a unique identifier and receiving the data by connecting to a data transmitting device for transmitting data,
Communication control means for detecting connection to and disconnection from an external device that communicates using the same protocol as the data transmission device, and acquiring a unique identifier from the connected external device when detecting that the external device is connected When,
When disconnection of the connection with the data transmission device is detected during command transmission to the data transmission device in which the connection is detected, a unique identifier obtained from the external device in which the connection is detected after disconnection, and the pre-disconnection A data reception that compares a unique identifier acquired from the data transmission device and determines that the external device is the data transmission device when they match, and transmits a disconnection command to the data transmission device A data receiving apparatus comprising: a control unit. A data receiving device having a unique identifier and receiving the data by connecting to a data transmitting device for transmitting data,
Communication control means for detecting connection to and disconnection from an external device that communicates using the same protocol as the data transmission device, and acquiring a unique identifier from the connected external device when detecting that the external device is connected When,
When disconnection of the connection with the data transmission device is detected while waiting for communication with the data transmission device with connection detected, the unique identifier acquired from the external device with connection detected after disconnection, and the connection before disconnection Data that is compared with the unique identifier acquired from the data transmission device, and if both match, determines that the external device is the data transmission device, and returns to a communication standby state without issuing a communication error A data receiving apparatus comprising: a reception control means. An image forming apparatus that has a unique identifier and receives the image data by connecting to a scanner apparatus that transmits the read image data,
A communication control means for detecting connection to and disconnection from an external device that communicates with the same protocol as the scanner device, and acquiring a unique identifier from the connected external device when detecting that the external device is connected; ,
When disconnection of the scanner device is detected while receiving image data from the scanner device from which the connection has been detected, a unique identifier acquired from the external device from which the connection has been detected after disconnection, and the scanner device And a data reception control means for determining that the external device is the scanner device and transmitting a data transmission resumption request to the scanner device when they match each other. An image forming apparatus.