JP4433873B2 - Printing apparatus and data transfer method - Google Patents

Description

  The present invention relates to a printing apparatus that performs printing in units of pages, and more particularly, to a printing apparatus that enables an appropriate flying start even in duplex printing.

  In general, in a so-called page printer that executes print processing in units of pages, processing for receiving image data transmitted from a host device and storing it in a memory, and processing for reading out the stored image data and transferring it to a print engine And done. In such a page printer, since the print engine executes print processing in units of pages in a continuous operation, the data transfer cannot be stopped in the middle of the page after the data transfer to the print engine is started. Therefore, the image data to be transferred to the print engine needs to be received and stored in the memory when reading.

  By waiting for the image data for one page to be stored in the memory and then starting the transfer of the page to the print engine, the above condition is satisfied, and in the print processing in the print engine Although the situation that the data is not in time does not occur, there is a problem that the start time of the printing process in the print engine is delayed.

  Therefore, a so-called flying start has been proposed in which transfer to the print engine is started when a certain amount of image data is stored without waiting for the image data for one page to be stored. With such flying start, the start time of the printing process in the print engine can be advanced, and the throughput in the printer can be improved.

  Regarding the timing of this flying start, there is a situation that data is not in time for the printing process in the print engine, that is, a printing failure (hereinafter referred to as an underrun error) due to the fact that the image data to be transferred is not stored in the memory. It is better to be early in the range where it does not occur, and some proposals have been made on how to determine such timing (for example, the method described in Patent Document 1 below).

On the other hand, some page printers can perform double-sided printing in which printing is performed on both sides of one printing medium, and such double-sided printing or single-sided printing is performed based on control information transmitted from the host device. In duplex printing, as described above, printing is performed on both sides of one sheet of paper, so that the sheet after printing on one side (for one page) is held in the printer and the other side ( The second page) is awaited for printing, but normally the second page cannot be waited for a certain period of time, and therefore the printing process for the first page and the second page is performed continuously. That is, the print engine of a page printer that continuously processes one page in single-sided printing continuously processes two pages in double-sided printing.
JP 2000-168175 A

  As described above, there are cases where double-sided printing is performed in a page printer, but the technology using the flying start in double-sided printing has not been shown so far.

  In addition, if the above-described flying start method for normal (single-sided) printing is simply applied to double-sided printing, transfer processing to the print engine is started independently for each side, and the first page There is a case where the printing process and the printing process for the second page cannot be performed continuously. Therefore, there may be a case where the above-described condition of performing the continuous processing of the print engine at the time of double-sided printing may not be satisfied, which causes a problem.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a printing apparatus that performs printing on a page-by-page basis and that enables an appropriate flying start even during double-sided printing.

  To achieve the above object, according to one aspect of the present invention, there is provided a printing apparatus capable of duplex printing in which image data transmitted from a host apparatus is received and a print engine performs printing based on the received image data. Is a data storage means for storing the received image data and a means for reading out the image data stored in the data storage means and transferring it to the print engine side. During the reception of the image data of the page, without starting data transfer to the print engine for the page, the page 1 is received during or after the reception of the image data of the second page of the duplex printing. Data transfer means for starting data transfer to the print engine for the second page and the second page. Therefore, according to the present invention, during double-sided printing in which double-sided processing is continuously performed in the print engine, it is possible to reduce an error that data reception is not in time for data transfer to the print engine.

  Furthermore, in the above-described invention, a preferable aspect thereof is characterized in that the start timing of data transfer to the print engine side is determined based on the image data of the second page.

In order to achieve the above object, another aspect of the present invention provides a printing apparatus capable of duplex printing in which image data transmitted from a host apparatus is received and a print engine performs printing based on the received image data. Are a data storage means for storing the received image data, and a means for reading out the image data stored in the data storage means and transferring it to the print engine side, and receiving the image data for one page. When the timing of flying start for starting data transfer to the print engine for the page before completion is set for each page, the image data of the first page of the double-sided printing at the time of the double-sided printing During the reception, the data transfer to the print engine side is not started for the page, and before the second page of the duplex printing is set. Based on the timing of the flying start, starts the data transfer to the first page and the second page the print engine side for that it has a data transfer means.

Furthermore, in the above-described invention, a preferable aspect thereof is that the flying start timing set for the second page is corrected in advance during reception of the image data for the second page. It is characterized by. As a result, it is possible to perform an efficient and less dangerous flying start.

  In order to achieve the above object, another aspect of the present invention is capable of duplex printing in which image data transmitted from a host device is received and stored, and a print engine performs printing based on the stored image data. In the data transfer method of the stored image data to the print engine in a simple printing apparatus, during the double-sided printing, during reception of the image data of the first page of the double-sided printing, The data transfer to the print engine is started for the first page and the second page during or after receiving the image data of the second page of the duplex printing without starting the data transfer to It is.

  In order to achieve the above object, still another aspect of the present invention provides duplex printing in which image data transmitted from a host device is received and stored, and a print engine performs printing based on the stored image data. In a data transfer method of the stored image data to the print engine in a possible printing apparatus, data transfer to the print engine for the page is started before reception of the image data for one page is completed When the timing of the flying start to be set is set for each page, during the duplex printing, during the reception of the image data of the first page of the duplex printing, the data transfer of the page to the print engine side is performed. Without starting the first page, and based on the flying start timing set on the second page of the duplex printing, It is to start data transfer to the print engine side for the serial second page.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

  Embodiments of the present invention will be described below with reference to the drawings. However, this embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a configuration diagram according to an embodiment of a printing apparatus to which the present invention is applied. The printer 2 shown in FIG. 1 is a printing apparatus according to the present embodiment. When double-sided printing is performed, even if the flying start is set, the data to the print engine is received during reception of the first page of data. The data transfer for both sides is started during or after the reception of the second page without performing data transfer, and proper printing is performed without causing an underrun error even during double-sided printing. .

  A host computer 1 shown in FIG. 1 is a host device that makes a print request to the printer 2 and can be configured by a general-purpose computer such as a so-called personal computer. The host computer 1 is provided with a print request source application and a printer driver that generates print data to be transmitted to the printer 2 in response to a request from the application (both not shown). In this printer driver, an image to be printed is generated as image data expressed by a color (for example, CMYK) used in the printer 2, and a header which is various control information is added to the generated image data for each page. The print data is generated. The generated print data is compressed and transmitted to the printer 2.

  The printer 2 is a page printer that receives print data transmitted from the host computer 1 and executes printing in units of pages, and includes a controller 10 and a print engine 20 as shown in FIG. The controller 10 receives the print data, performs necessary processing, and then performs a series of processing to be passed to the print engine 20 as an I / F 11, a DMA controller 12 (data transfer means), a data decompression circuit 13, a video. A controller 14 is provided. These processing circuits can be configured by a dedicated hardware logic circuit such as an ASIC, for example.

  The controller 10 also includes a CPU 15 (data transfer means) that controls various processes performed in the printer 2, a DRAM 16 (data storage means) mainly used as a reception buffer memory, and a ROM 17 (data transfer means) that stores programs and the like. As shown in FIG. 1, they are connected to each other so as to be able to exchange data.

  First, print data transmitted from the host computer 1 is received by the I / F 11, and image data included in the received print data is transferred to the DRAM 16 by the DMA controller 12 and stored in the DRAM 16. The stored image data is read from the DRAM 16 by the DMA controller 12 at a predetermined timing and transferred to the data decompression circuit 13. Since the transferred image data is compressed as described above, the data decompression circuit 13 performs decompression processing, thereby generating video data. The generated video data is transmitted to the print engine 20 by the video controller 14 in synchronization with the vertical synchronization signal and horizontal synchronization signal from the print engine 20. The print engine 20 performs printing based on the transmitted video data, and forms an image on a print medium such as paper.

  A series of processing performed in the printer 2 is controlled by the CPU 15 in accordance with a program recorded in the ROM 17. The printer 2 is characterized by the timing of transferring the image data stored in the DRAM 16 to the print engine 20 side in the series of processes. Hereinafter, the print data transmitted from the host computer 1 to the print engine 20 is received. The process up to the start of the transfer process will be specifically described.

  FIG. 2 is a flowchart illustrating processing from reception of print data to transfer to the print engine 20. Here, processing for print data for one job transmitted from the host computer 1 is shown. When reception of print data for one job is started, it is first determined whether or not the job is duplex printing (step S10). FIG. 3 is a diagram schematically showing print data transmitted from the host computer 1. FIG. 3 shows data for one job, and the printer 2 receives the data in the order from left to right and from top to bottom in the figure.

  The header (1) is common information for the entire job added to the head of the job, and includes information such as whether the job is duplex printing or simplex printing. Thereafter, data of each page (a in FIG. 3) continues, but a header (2) is added to the head of the data of each page. The header (2) includes control information of the page, and in the case of double-sided printing, includes information on whether the page is the front side or the back side. The header (2) is followed by image data of the page, but the image data is handled in units of bands which are areas obtained by dividing one page at a predetermined interval in the height direction. Accordingly, the image data is hereinafter referred to as band data. Thereafter, the data of each page is similarly repeated. However, in the case of double-sided printing, for example, as shown in FIG. 3, data on the back surface (first page) and data on the front surface (second page) are repeated. The header (3) includes information indicating the end of the job.

  Returning to FIG. 2, the determination as to whether or not the double-sided printing is performed (step S10) is performed by interpreting the information included in the header (1) described above. As a result, when the printing is not duplex printing, that is, when printing is simplex (No in step S10), the process proceeds to step S50. On the other hand, if duplex printing is selected (Yes in step S10), it is checked whether there is data for the first page (step S20). If not (No in step S20), the process proceeds to step S40. Transition. If there is a first page (Yes in step S20), the band data of the first page is received and stored in the DRAM 16 (step S30). In such a case, all the band data of the first page is stored in the DRAM 16, and at this point, the transfer process of the data to the print engine 20 is not yet started.

  Next, it is checked whether or not there is data on the second page (step S40). If there is no data (No in step S40), the process proceeds to step S70, and if there is (Yes in step S40). The process moves to step S50.

  In step S50, it is determined whether or not flying printing (flying start) is set for printing the page. Here, this determination is made for the second page in the case of duplex printing, and for each page in the case of single-sided printing. Such a determination is made based on the information included in the header (1) or the header (2) described above, settings on the printer 2 side, and the like. Normally, the header (2) includes the data transfer timing to the print engine 20, and a determination is made based on this information.

  FIG. 4 is a diagram for explaining print data for one page. FIG. 4 shows an example of the band data configuration for the part a shown in FIG. In this example, the band data is composed of CMYK four-color data, but there are two configurations shown in FIGS. 4A and 4B depending on the order of transmission from the host computer 1 to the printer 2. .

  FIG. 4A shows a configuration of print data received by the printer 2 in the case of performing transmission by so-called plane sequential transmission in which all band data is transmitted for each color for one page. In this case, for example, as shown in the figure, for one page, first, all C band data is received, and then all M band data, all Y band data, and all K band data are sequentially received. Receive data. This plane sequential transmission / reception is used when the print engine 20 performs a flying start with a 4-cycle page printer that executes printing processing for each color.

  On the other hand, FIG. 4B shows the print data received by the printer 2 in the case of performing so-called band sequential transmission in which band data of all colors constituting the image data is transmitted for each band. The configuration is shown. In such a case, for example, as shown in the figure, C band data, M band data, Y band data, and K band data in the first band are sequentially received. Band data is sequentially received for. This band sequential transmission / reception is used by a tandem page printer or the like that performs printing processing of each color in parallel in the print engine 20.

  In the example shown in FIG. 4, when one color image data in one band is set as one band data, the image data for one page is composed of n band data. The header added before the band data includes various control information. For example, in the case of double-sided printing, information on which side of the data is the front and back, paper size at the time of printing, Information such as the number n of band data composing the image data of one page and the transfer processing start timing m indicating the timing of flying start is included.

  This transfer processing start timing is a timing at which processing for transferring the band data stored in the DRAM 16 to the print engine 20 side is started. In this example, the timing is expressed by the number of received band data, and the transfer processing start timing m means that the data transfer should be started when m pieces of band data are received. This value is assumed to be set on the host computer 1 side. However, the transfer process start timing may be determined on the printer 2 side without setting the transfer process start timing on the host computer 1 side, that is, without including the value of m in the header.

  Returning to FIG. 2, whether or not the flying printing is set (step S50) is determined in the example shown in FIG. 4 if the transfer processing start timing m is smaller than n. Is determined to be set. In this determination, if it is determined that flying printing is not set (No in step S50), all the band data for one page is received and stored in the DRAM 16 (step S60). Then, the process of transferring the data stored in the DRAM 16 to the print engine 20 side is started (step S70). Here, in the case of duplex printing, transfer processing is started for both the first page data received and stored in step S30 and the second page data received and stored in step S60. In the case of single-sided printing, transfer processing is started for one page of data received and stored in step S60. More specifically, the start of the transfer process is to issue a request to start the data transfer process for the page. In normal cases, the transfer process for the page is started immediately based on the request, but the process according to the request may be in a standby state when the transfer process has not been completed for the previous page. is there.

  Thereafter, for the data reception and transfer start processing described here, the processing proceeds to step S120.

  On the other hand, if it is determined in step S50 that flying printing is set (Yes in step S50), it is checked whether or not the transfer processing start timing is reached (step S80). Usually, at this time, that is, immediately after receiving the header (2) of the page, the transfer processing start timing is rare, but when it reaches the timing (Yes in step S80), the step The process proceeds to S100.

  On the other hand, when the transfer processing start timing has not been reached (No in step S80), data reception of the page is continued and one band data is received (step S90). Thereafter, the process returns to step S80 to determine again whether or not the transfer processing start timing has been reached. The steps S90 and S80 are repeated until the transfer processing start timing is reached. For example, in the example shown in FIG. 4, if the transfer process start timing m = 20, it is determined that the transfer process start timing has been reached when 20 band data are received. When m = n, it is determined that the transfer processing start timing has been reached when all band data for the page has been received. Further, when m = 0, it is determined that the transfer processing start timing has been reached immediately after receiving the header (2).

  Note that the determination based on FIG. 4 described above is an example, and the transfer processing start timing can be determined by another method. Also, the index for determining the transfer processing start timing can be the reception time or the size of the received data, not the number of received band data. In such a case, step S90 is a process of data reception for a predetermined time or data reception of a predetermined size.

  In this way, when the transfer process start timing is reached (Yes in step S80), the data transfer process to the print engine 20 side is started (step S100). As in the case of step S70 described above, in double-sided printing, data transfer is started for the first and second pages, and in single-sided printing, data transfer is started for the page that is receiving data. Here, the transfer process start means that a request to start the data transfer process is issued. At this time, if not all band data has been received for the page, a flying start is performed. Thereafter, the remaining band data of the page is received (step S110), and the process proceeds to step S120. If all the band data has been received for the page at the time when the transfer process is started (step S100), the process proceeds to step S120 without receiving data in step S110.

  After step S70 described above or after step S110, it is checked whether or not the job has been completed (step S120). Such a check can be performed, for example, depending on whether the next received data is the header (2) or the header (3). As a result of the check, if the job is not yet completed (No in step S120), the process returns to step S20 when the job is duplex printing, and the process returns to step S20 when the job is simplex printing. Returning to S50, the process for the next page is similarly performed. On the other hand, if the job has ended (Yes in step S120), the processing for the job is ended.

  As described above, the printer 2 does not start transferring the received data to the print engine 20 during data reception on the first page during double-sided printing, regardless of whether or not flying printing is set. During the reception of the data of the second page or after the completion of the reception, the transfer processing of the data of both pages to the print engine 20 is started. Also, the timing of flying start (start of transfer of both pages) performed during reception of data for the second page is determined in the same way as when the second page is printed on one side.

  Therefore, even when a flying start is made at the time of double-sided printing, the data for the first page is stored in the DRAM 16 at the time when the printing process is continuously performed by the print engine 20 for both sides. With respect to the second page, since the certainty that data reception is in time for the above printing process is higher than that in the case of single-sided printing, it is possible to reduce the risk of occurrence of an error due to inadequate data reception. In addition, at the time of starting the above-described printing process for double-sided printing, the header information (header (2)) has already been received for the second page and the control information has been grasped. Risk can be reduced. As described above, the printer 2 can perform appropriate flying printing with few problems even during double-sided printing.

  Next, a specific example of determining whether or not the transfer processing start timing described above has been reached (step S80 in FIG. 2) will be described. FIG. 5 is a flowchart illustrating an example of a transfer process start timing determination process. The processing content shown in FIG. 5 is a concrete implementation of step S80 in FIG. In this specific example, as shown in FIG. 4, the number m of bands at the transfer processing start timing is set on the host computer 1 side and included in the header of the print data transmitted to the printer 2. To do.

  First, when it is determined from the information of the header (2) that flying printing has been set (step S50), it is checked whether or not all band data has been received for the page (step S81). If completed (Yes in step S81), it is determined that the transfer process start timing has been reached, and the process proceeds to step S100 described above.

  On the other hand, if data reception has not been completed for the page (No in step S81), the process proceeds to step S82. In step S82, it is checked whether or not m pieces of band data, which is the set transfer processing start timing, have been received, and reception of band data (step S90) is repeated until m pieces of band data are received.

  When the m pieces of band data are received (Yes in step S82), the printer 2 calculates the reception speed (step S83). FIG. 6 is a time chart for explaining the transfer processing start timing. A solid line portion in (1) of FIG. 6 indicates a period from the start of reception of the band data of the target page to reception of the m pieces of band data. The reception speed is calculated by dividing the data size S0 received during this time by the reception time T0 during this time.

  Next, the average size of the band data received up to this point is obtained (step S84). As described above, since the band data is transmitted after being compressed on the host computer 1 side, the size differs for each band data depending on the contents of the data. The average size of 1-band data is obtained by dividing the data size S0 received so far by m. In the example illustrated in FIG. 6, the number n of band data of the target page is 100, and the transfer processing start timing m set in the header is 25. Therefore, in this example, S0 is divided by 25.

  Next, the size S1 of the remaining band data not yet received of the target page is predicted (step S85). The remaining data size S1 is obtained by multiplying the average size of the obtained one band data by the number of remaining band data. In the example shown in FIG. 6, the value of S0 ÷ 25 × (100−25) is S1. Then, a time T1 required to receive the obtained remaining data size S1 is predicted (step S86). Specifically, the reception time T1 is obtained by dividing the remaining data size S1 by the reception speed obtained in step S83.

Thereafter, the printer 2 compares the predicted reception time T1 with the time T2 for transferring one page of band data stored in the DRAM 16 to the print engine 20 (step S2).
87). More precisely, the transfer time T2 means the time from the read start time to the read end time for one page of band data from the DRAM 16. The transfer time T2 is a value obtained by multiplying the number of band data of one page by a constant, and can be easily obtained using the value of n included in the header of the print data.

  If the reception time T1 is smaller in the comparison between the reception time T1 and the transfer time T2 (Yes in step S87), it is determined that the transfer process start timing has been reached at this point, and the process proceeds to the above-described step S100. On the other hand, as shown in (2) of FIG. 6, if the transfer time T2 is shorter (No in step S87), it is determined that the transfer processing start timing has not yet been reached, and the value of m is corrected (step S88). . At this time, the value of m is naturally updated to a value larger than the previous value, but various methods can be used for this correction.

  As shown in (3) of FIG. 6, in the example of FIG. 6, at this time, the time when the reception time T1 is expected to be smaller than the transfer time T2 is determined as the time when 55 band data is received, for example. Is done. In such a case, this m ′ = 55 value can be corrected to a new m value. Further, the value of m can be corrected by adding a predetermined value regardless of m ′. In the example of FIG. 6, for example, 10 is added to m = 25, and the value of m is updated to 35. In the case of this method, after updating the value of m, the predetermined value (for example, 10) is added every time it becomes No in step S87 again and the value needs to be updated.

  Furthermore, the value of m ′ may be compared with a value of 2m, that is, a value (m + m) obtained by further adding the initially set value of m, and updated to a smaller value. . In the example of FIG. 6, since the value of 2m is smaller as shown in (3) of FIG. 6, the value of m is updated to 50. In this method, every time it is necessary to update the value of m, the value of m initially set to the value of m at that time (in this specific example, the value set in the header (2)) is changed. The added value is compared with the value of m ′ at that time, and the smaller value is selected.

  Thus, when the value of m is updated, the process proceeds to step S90, and reception of band data is performed until the updated number m of band data is received. When the updated number m of band data has been received and not all the data has been received yet (Yes in step S82), the processing from step S83 described above is performed. Thereafter, the same processing is repeatedly executed until it is determined that the reception time T1 is smaller than the transfer time T2.

  As described above, in the specific example described based on FIG. 5, during the reception of data, it is repeatedly checked whether the set transfer processing start timing is appropriate based on the reception status up to that time. Is done. Accordingly, the flying start is performed based on the transfer processing start timing with high accuracy, and the risk of causing problems such as an underrun error is reduced. Also, in the m update process (step S88) described above, the value of m ′ is increased at a stroke until the value of m ′, that is, the reception time T1 is expected to be smaller than the transfer time T2 at that time. By not doing so, it is possible to start the flying start without any problem as soon as possible, and the throughput of the printer 2 can be improved. Usually, in the transmission processing of print data for one page from the host computer 1, in the first half, compression processing of data to be transmitted, storage processing in the host computer 1, and transmission processing to the printer 2 are performed in parallel. In the latter half, only the process of transmitting the stored data to the printer 2 is performed. Therefore, the data reception process in the printer 2 is also usually performed faster after the beginning of one page. As a result, the effect of checking the timing of flying start by updating to a value smaller than the value of m ′ described above can be obtained.

  As described above, in the printer 2 according to the present embodiment, when flying printing is set for each page, in the case of duplex printing, printing processing for both sides is continuously performed in the print engine 20. Therefore, the data transfer to the print engine 20 is not started during the data reception of the first page. Therefore, there is little risk of causing a situation that data reception is not in time for duplex printing, and proper flying printing is possible even during duplex printing.

  The present invention can be applied to both a so-called 4-cycle page printer and a tandem page printer.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

1 is a configuration diagram according to an embodiment of a printing apparatus to which the present invention is applied. It is the flowchart shown about the process from data reception to transfer. 4 is a diagram schematically showing print data transmitted from a host computer 1. FIG. It is a figure for demonstrating the printing data for 1 page. It is the flowchart which showed an example of the judgment process of the transfer process start timing. It is a time chart for demonstrating the transfer process start timing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Host computer, 2 Printer, 10 Controller, 11 I / F, 12 DMA controller (data transfer means), 13 Data decompression circuit, 14 Video controller, 15 CPU (data transfer means), 16 DRAM (data storage means), 17 ROM (data transfer means), 20 print engine

Claims (2)

A printing apparatus capable of duplex printing in which image data transmitted from a host device is received and a print engine performs printing based on the received image data,
Data storage means for storing the received image data;
Means for reading out image data stored in the data storage means and transferring the image data to the print engine;
When the timing of the flying start for starting the data transfer to the print engine for the page before the reception of the image data for one page is completed is set for each page,
During the duplex printing, during the reception of the image data of the first page of the duplex printing, the page is set to the second page of the duplex printing without starting data transfer to the print engine side. Data transfer means for starting data transfer to the print engine side for the first page and the second page based on the timing of the flying start,
The printing device obtains the reception speed from the received data size and the reception time of the already received image data while receiving the image data of the second page, and arranges all the image data of the page in the order of reception. The predicted data size of the remaining data not yet received on the page is obtained from the position of the last received data at that time and the received data size, and the remaining data is calculated from the reception speed and the predicted data size. It obtains a predicted time required for receiving, printing apparatus the timing of flying start is set to the second page, from a predetermined timing, and correcting, based on the predicted time. Data stored in the print engine of the stored image data in a printing apparatus capable of receiving and storing image data transmitted from a host device and capable of duplex printing in which the print engine performs printing based on the stored image data A transfer method,
When the timing of the flying start for starting the data transfer to the print engine for the page before the reception of the image data for one page is completed is set for each page,
During the duplex printing, during the reception of the image data of the first page of the duplex printing, the page is set to the second page of the duplex printing without starting data transfer to the print engine side. Based on the timing of the flying start, data transfer to the print engine side for the first page and the second page is started,
The printing device obtains the reception speed from the received data size and the reception time of the already received image data while receiving the image data of the second page, and arranges all the image data of the page in the order of reception. The predicted data size of the remaining data not yet received on the page is obtained from the position of the last received data at that time and the received data size, and the remaining data is calculated from the reception speed and the predicted data size. obtains a predicted time required for receiving, said second timing of flying start is set to page, from a predetermined timing, the data transfer method and correcting on the basis of the estimated time.

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