JP2008046828A - Print system, printing device, data communication method for print system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a print system capable of making effective use of a communication line and shortening transfer time of print data. <P>SOLUTION: In the network print system, a PC 100 is connected with a network printer 200 via a LAN 300. An interface monitor 150 of the PC 100 determines a packet size of a packet regarding the designated print data on the basis of a data volume of the designated print data to be transmitted to the network printer 200 and a traffic volume through the LAN 300. The packet including the print data is transmitted from the PC 100 to the network printer 200 on the basis of the determined packet size. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printing system, a printing apparatus, and a printing system in which a transmission source apparatus that transmits print data and a printing apparatus that executes print processing based on the print data transmitted from the transmission source apparatus are connected via a communication line. The present invention relates to a data communication method.

  In data transmission in a network print system in which a plurality of computers and a network printer are connected to a network line, the maximum data size of data that can be transmitted by the computer to the network printer, that is, the packet size is, for example, the maximum transfer on the network line. Unique by unit (MTU).

  Some network print systems as described above are constructed such that flow control is not performed during data communication between a computer and a network printer (see, for example, Patent Document 1).

In this Patent Document 1, the personal computer sets the communication buffer size to a value smaller than the default value according to the communication data amount of data to be transmitted, and transmits data based on the set communication buffer size to the network printer. Like to do.
JP 2000-181645 A

  However, in the technique disclosed in Patent Document 1, when the traffic on the network line is large (congested), data loss (packet loss) may occur depending on the packet size of the transmitted packet. Yes, it is necessary to retransmit the same packet as the data lost packet. Therefore, there is a problem that efficient data transmission cannot be performed.

  Also, if there is a lot of traffic on the network line, the probability that the packet itself sent from the personal computer to the network printer will be delayed depending on the amount of traffic, so that efficient data transmission cannot be performed. The problem is inherent.

  As described above, it takes more time than necessary to transmit data from the personal computer to the network printer, resulting in a problem that the print processing time becomes longer.

  Therefore, the present invention provides a printing system, a printing apparatus, and a data communication method for a printing system that can achieve efficient use of a communication line and can reduce the transfer time of print data. Objective.

  In order to solve the above problem, a printing system according to a first aspect of the present invention includes: a transmission source device that transmits print data; and a printing device that executes print processing based on the print data transmitted from the transmission source device. A printing system that is connected via a communication line and transmits / receives data between these devices according to a predetermined communication protocol, wherein the transmission source device has a data amount of predetermined print data to be transmitted to the printing device, and Packet size determination means for determining a packet size of a packet related to the predetermined print data based on information on at least one of the traffic amount on the communication line and the load state of the printing apparatus, A packet based on the packet size determined by the packet size determining means is transmitted to the printing apparatus.

  According to a second aspect of the present invention, in the first aspect of the invention, the packet size determining unit receives the predetermined packet from the time when the predetermined packet not including print data is transmitted to the printing apparatus. The predetermined print data based on the communication time up to the reception time when receiving an indication of the reception time of the predetermined packet transmitted from the printing apparatus and the data amount of the predetermined print data Determining the packet size of the packet.

  According to a third aspect of the present invention, in the first aspect of the present invention, the packet size determining means receives the predetermined packet from the time when the predetermined packet not including print data is transmitted to the printing apparatus. A packet size of a packet related to the predetermined print data is determined based on a communication time up to a point of receiving an acknowledgment transmitted from the printing apparatus and a data amount of the predetermined print data; It is characterized by that.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein the transmission source device includes a plurality of different communication time information, a plurality of different data amount information, and a plurality of packet size information. Storage means for storing the associated information, wherein the packet size determining means includes the communication time obtained by transmitting the predetermined packet, the data amount of the predetermined print data, and the storage means. A packet size of a packet related to the predetermined print data is determined based on the stored content.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the packet size determining means inquires of the printing apparatus about a load state, and as a result of the inquiry Information indicating the load status returned from the printing apparatus is acquired, and the packet size of the packet related to the predetermined print data is determined based on the acquired information indicating the load status and the data amount of the predetermined print data. It is characterized by that.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the printing apparatus receives the predetermined packet transmitted from the transmission source apparatus. It has a reception time notifying means for transmitting to the packet size determining means that a reception time when a predetermined packet is received is indicated.

  A seventh aspect of the present invention provides the printing apparatus according to any one of the first to sixth aspects, wherein the printing apparatus receives the inquiry about the load state from the transmission source apparatus. Load status notifying means for returning information indicating the print processing status to the transmission source device as a result of the inquiry.

  According to an eighth aspect of the present invention, in the invention according to the seventh aspect, the load state notifying unit is configured to execute a print process for print data included in a packet from the transmission source device that has already been received. In the meantime, when there is an inquiry about the load state, information indicating the data size of receivable data is returned to the transmission source device as a result of the inquiry.

  According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the packet size determining means transmits a packet including print data based on the already determined packet size. To the packet size that has already been determined based on the response time from the reception of the packet indicating that the packet has been received to the time of receiving an acknowledgment indicating the acknowledgment and the amount of print data to be transmitted It is characterized by that.

  The invention according to claim 10 is the invention according to any one of claims 1 to 9, wherein flow control is not performed in data communication between the transmission source device and the print data. It is characterized by that.

  In order to solve the above problems, a printing apparatus according to an embodiment of the present invention is connected to a transmission source apparatus that transmits print data via a communication line, and has a flow control function with the transmission source apparatus. A printing apparatus that performs data communication according to a predetermined communication protocol, and when receiving an inquiry about a load state from the transmission source apparatus, information indicating a print processing status of the printing apparatus as a result of the inquiry Load state notifying means for sending a reply to the transmission source device.

  According to a twelfth aspect of the present invention, in the invention according to the eleventh aspect, the load state notifying unit prints print data included in a packet relating to predetermined print data from the transmission source apparatus that has already been received. When there is an inquiry about the load state while processing is being performed, information indicating the data size of receivable data is returned to the transmission source device as a result of the inquiry. .

  A thirteenth aspect of the present invention is the invention according to the eleventh or twelfth aspect of the present invention, wherein when a predetermined packet transmitted from the transmission source device and not including print data is received, the reception of the predetermined packet is received. It further comprises reception time notifying means for transmitting information indicating the time to the transmission source device.

  Furthermore, in order to solve the above problem, the data communication method of the printing system of the present invention according to claim 14 is the data communication of the printing system in which the transmission source device transmits a packet related to predetermined print data to the printing device through the communication line. A method is provided in which, without performing flow control relating to data communication between the transmission source device and the printing device, the transmission source device transmits a packet including print data from the printing device. A packet size is determined based on the acquired load state of the printing apparatus and at least one of the traffic amount on the communication line and the data amount of the predetermined print data, and based on the determined packet size, A packet including print data is transmitted to the printing apparatus.

  According to the present invention, it is possible to efficiently use a communication line and to shorten the print data transfer time, thereby shortening the print processing time in the printing apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  In the present embodiment, a network printing system to which the printing system of the present invention is applied will be described. The transmission source device is a host computer, the printing device is a printer, that is, a shared network printer, and the communication line is a network such as a local area network (hereinafter referred to as “LAN”).

  In the present embodiment, the transmission source device and the printing device perform data communication according to a predetermined communication protocol, for example, TCP (Transmission Control Protocol) / IP (Internet Protocol). Further, flow control is not performed in the data communication.

  (Embodiment 1)

  FIG. 1 shows the overall configuration of a network print system according to Embodiment 1 of the present invention.

  As shown in FIG. 1, in a network print system 1, one or a plurality of host computers (hereinafter referred to as “PCs”) 100 and a network printer 200 are connected to a LAN 300 as a transmission medium that is a shared network.

  In such a network print system 1, a network printer (printing apparatus) 200 can print print data from all PCs (transmission source apparatuses) 100 connected to a LAN (communication line) 300.

  The PC 100 includes a display unit 101 that displays predetermined display information, an input unit 102 that inputs input information such as a print instruction for print data, a storage unit 103 that stores predetermined information, and a communication interface (hereinafter referred to as a communication interface). (Referred to as “communication I / F”) 104 and a control unit 105 that controls these components.

  The storage unit 103 has a first storage area, a second storage area, and a third storage area (not shown).

  The first storage area is a predetermined application, a predetermined operating system, a program corresponding to a predetermined communication protocol, a predetermined device driver, a program corresponding to a processing procedure described later (see FIGS. 3 and 5 to 9), etc. , An area for storing a predetermined program and a packet size determination table (see FIG. 4), which will be described later, and is composed of, for example, a hard disk or a ROM (read only memory).

  The second storage area is an area for storing print data, and includes, for example, a hard disk, a RAM (a read / write memory as needed), and the like.

  The third storage area is an area (work area) that stores a program read from the first storage area, print data read from the second storage area, and data exchanged during data communication. For example, a RAM. In addition, the third storage area has a work area that is used for predetermined arithmetic processing such as obtaining a packet size to be described later.

  The control unit 105 reads and executes a predetermined program from the first storage area to the third storage area, thereby performing data communication regarding print processing with the network printer 200, for example. The control unit 105 controls the entire PC 100, and includes, for example, a CPU (Central Processing Unit).

  The network printer 200 includes a storage unit 201 that stores predetermined information, a printing unit 202 that executes image formation processing (printing processing), and a communication interface (hereinafter referred to as “communication I / F”) 203 that controls an interface for communication. A control unit 204 that controls the entire network printer 200 including these components is provided.

  The communication I / F 203 is, for example, a NIC (Network Interface Card), a storage unit (not shown) that stores predetermined information, and a control unit (not shown) that performs data communication with a communication partner device. ).

  In the communication I / F 203, a storage unit (not shown) exchanges data when communicating with a PC 100 and a first storage area (not shown) such as a ROM that stores a program corresponding to a predetermined communication protocol. For example, a second storage area (not shown) such as a RAM. The control unit performs data communication with the PC 100 by executing a program stored in the first storage area.

  The storage unit 201 stores, for example, a first storage area (not shown) such as a ROM that stores predetermined firmware, firmware read from the first recording area, and print received via the communication I / F 203. It has a second storage area (not shown) such as a RAM for storing data.

  The printing unit 202 prints an image corresponding to the print data on a recording sheet under the control of the control unit 204.

  The control unit 204 reads out and executes predetermined firmware from the first storage area of the storage unit 201 to the second storage area, thereby generating a print image based on the received print data, for example, Is requested to the printing unit 202.

  FIG. 2 shows the configuration of the protocol stack of the network print system according to the first embodiment.

  The PC 100 has functions of an application 110, an operating system (hereinafter referred to as “OS”) 120, a printer driver 130, a print spooler 140, an interface monitor 150, and a TCP / IP / socket interface (hereinafter referred to as “socket interface”) 160. Have.

  The application 110 generates print data, instructs a print job, and the like.

  The printer driver 130 is a device driver for a printer corresponding to the network printer 200.

  When a shared network printer 200 is used in the case of a network print system in which a plurality of PCs 100 are connected, the print spooler 140 plays a role of adjusting a print job transmitted to the network printer 200.

  That is, the print job transmitted from each PC 100 is adjusted so as to be transmitted from the print spooler 140 when the network printer 200 is not executing a print process for a print request from another PC.

  The print spooler 140 creates a print queue for the interface monitor 150 and executes processing for each print job.

  The interface monitor 150 has a network monitoring function (communication monitoring function) and a packet size determining unit function. This packet size determining means includes the following functions (1) to (4).

  (1) Based on the data amount of predetermined print data to be transmitted to the network printer 200 and the traffic amount on the LAN 300, the packet size of the packet related to the predetermined print data is determined.

  (2) When a message indicating the reception time of the predetermined packet transmitted from the network printer 200 that has received the predetermined packet is received from the time when the predetermined packet not including print data is transmitted to the network printer 200 The packet size of the packet to be transmitted is determined based on the communication time (arrival time) until the reception time and the amount of predetermined print data to be transmitted.

  (3) Communication time (response time) from the time when a packet is transmitted to the network printer 200 to the time when an affirmative acknowledgment (ACK signal) transmitted from the network printer 200 that received the packet is received, and to be transmitted The packet size of the packet to be transmitted is determined based on the data amount of predetermined print data.

  (4) Response from when a packet (packet including print data) based on the already determined packet size is transmitted to when a positive acknowledgment (ACK signal) transmitted from the network printer 200 that has received the packet is received The already determined packet size is corrected based on the time and the data amount of predetermined print data to be transmitted.

  The socket interface 160 has a function for managing an interface with the LAN 300.

  Here, the application 110, the OS 120, the printer driver 130, the print spooler 140, the interface monitor 150, and the socket interface 160 are stored in the first storage area (hard disk, ROM, etc.) of the storage unit 103 of the PC 100 shown in FIG. ing.

  And the control part 105 implement | achieves each function of each component 110-160 mentioned above by reading and running each said program memorize | stored in the 1st storage area of the memory | storage part 103. FIG. As a result, data communication between the PC 100 and the network printer 200 becomes possible. In this case, the application 110, the printer driver 130, the print spooler 140, the interface monitor 150, and the socket interface 160 operate under the control of the OS 120.

  Such a PC 100 performs data communication with the network printer 200 in accordance with the rules of the OS 120. At this time, the PC 100 is configured to perform data communication with the network printer 200 via the interface monitor 150 to perform printing.

  That is, in the PC 100, print data from the application 110 for instructing a print job flows in the order of the printer driver 130, the print spooler 140, the interface monitor 150, and the socket interface 160 via the OS 120.

  The network printer 200 includes firmware (hereinafter referred to as “printer FW”) 210 that controls the printing unit 202 and a NIC (network interface card) 220.

  The printer FW 210 does not have a function of spooling print data (spool function), and prints the print job in accordance with the order of the print jobs requested to be sequentially printed. Further, the printer FW 210 does not accept the next print job until the printing of the previous print job is completed. That is, the next print job is not printed until the printing of the previous print job is completed. Further, the printer FW 210 generates a print image based on the received print data, and requests the printing unit 202 to perform print processing.

  Here, the printer FW 210 is stored in a first storage area (ROM or the like) of the storage unit 201 of the network printer 200 shown in FIG. The control unit 204 reads and executes the printer FW 210 from the storage unit 201, thereby realizing the function of the printer FW 210.

  The NIC 220 is a TCP / IP / socket interface (hereinafter referred to as a “socket interface”) having a function of controlling an interface between the NIC I / F 230, the interface monitor (print daemon) 240, and the LAN 300, which is an interface between the printer FW 210 and the NIC 220. ) 250.

  The interface monitor 240 has a function of monitoring the network (communication monitoring function) and a function of a reception time notification means for notifying the interface monitor 150 of the PC 100 that the reception time of the predetermined packet is indicated when the predetermined packet is received. And have.

  Since the NIC 220 corresponds to the communication I / F 203 as hardware, the communication I / F 203 illustrated in FIG. 1 can be replaced with the NIC 220.

  Here, the NIC I / F 230, the interface monitor 240, and the socket interface 250 are a first storage area (not shown) of a storage unit (not shown) in the communication I / F 203 (NIC 220) of the network printer 200 shown in FIG. ROM). Then, the control unit (not shown) of the communication I / F 203 (NIC 220) reads the above-described components 240 to 260 from the storage unit (not shown) and executes them, thereby functioning these components. Realize.

  In such a network printer 200, when the NIC 220 receives print data from the PC 100 via the LAN 300, the print data flows in the order of the socket interface 250, the interface monitor 240, the NIC / I / F 230, and the printer FW 210.

  In this series of printing operations, the NIC 220 can simultaneously respond to connection requests from 64 PCs, that is, 64 PCs 100, but the printer FW 210 can process only one print job. The next print job is not transmitted to the printer FW 210 until printing of the previous print job is completed.

  Therefore, a print request from another PC 100 is awaited by the print spooler 140 in each PC 100 until the printing process of the printer FW 210 is completed. Each print job is printed in order when the printer FW 210 becomes empty.

  In the first embodiment, the interface monitor 150 of the PC 100 and the interface monitor 240 of the network printer 200 do not have a flow control function, respectively. That is, flow control is not performed in data communication between the PC 100 and the network printer 200.

  In addition, the PC 100 and the network printer 200 confirm communication (communication) with each other using ICMP (Internet Control Message Protocol) determined by the TCP / IP standard protocol (RFC 792 / RFC 1812). .

  ICMP is a protocol for transferring IP (Internet Protocol) error messages and control messages, and is used to check the state of each other between network devices such as PCs and network printers connected by TCP / IP. It is the protocol used for

  The format of the ICMP packet includes a transmission destination IP address, an IP header including the transmission source IP address, and a data portion (ICMP message).

  This ICMP message is composed of 1-byte “Type”, 1-byte “Code”, and 2-byte “Checksum” fields. If necessary, an additional data field of a predetermined byte follows.

  The type of ICMP is roughly divided into a message used for investigation (“Query message”) and a message for notifying an error (“Error message”) depending on the nature of the Type field. The “Query message” is a message that responds to a survey command such as ping, in other words, a normal response.

  ICMP messages include an echo response (type 0), an echo request (type 8), a time stamp request (type 13), and a time stamp response (type 14).

  Next, a print job start process by the interface monitor 150 of the PC 100 of the network print system 1 will be described with reference to FIG.

  FIG. 3 is a follow chart showing the processing procedure of the print job start processing by the interface monitor 150.

  When the application 110 of the PC 100 executes a print job, print data flows to the interface monitor 150 via the OS 120, the printer driver 130, and the print spooler 140.

  When the interface monitor 150 is called from the printer driver 130 and starts operating, the interface monitor 150 initializes the socket interface 160 (step S101) and connects to the network printer 200 via the LAN 300, as shown in FIG. (Step S102), it is determined whether or not the connection is successful (step S103).

  Here, the connection means a state in which the PC 100 and the network printer 200 can perform data communication with each other.

  Next, when the interface monitor 150 determines in step S103 that the connection is not successful, the interface monitor 150 returns to step S102. When the interface monitor 150 determines that the connection has failed because no data is exchanged for a certain period of time, the interface monitor 150 releases the connection state.

  When the interface monitor 150 that has determined that the connection has succeeded in step S103 instructs the socket interface 160 to transmit an IP packet including an ICMP packet, the socket interface 160 follows the instruction of the interface monitor 150 to send an ICMP packet (transmit ICMP ICMP). An IP packet including the packet is sent to the network printer 200 via the LAN 300 (step S104).

  When the transmission IP packet is transmitted to the network printer 200 through the socket interface 160 in step S104, the interface monitor 150 waits for a response to the transmission ICMP packet from the network printer 200 through the socket interface 160.

  This is because the interface monitor 150 determines the traffic of the LAN 300 based on the response time from the time when the transmission IP packet is transmitted to the time when the response packet to the transmission ICMP packet included in the transmission IP packet from the network printer is received. This is to make a judgment (determine how busy the LAN 300 is).

  Therefore, the interface monitor 150 can recognize the transmission time when the transmission IP packet is transmitted and the reception time when the response packet from the network printer 200 is received.

  By the way, when the transmission IP packet is transmitted to the network printer 200 as described above, the interface monitor 150 determines whether there is a response to the transmission ICMP packet included in the transmission IP packet from the network printer 200, that is, the socket. It is determined whether an IP packet (this is a response IP packet) including an ICMP packet for response (this is a response ICMP packet) is received through the interface 160 (step S105).

  Next, if the interface monitor 150 determines in step S105 that there is a response from the network printer 200, that is, if it determines that a response IP packet has been received, the interface monitor 150 transmits the transmission IP packet to the network printer 200 ( The response time from the transmission time) to the time when the response IP packet from the network printer 200 is received (reception time) is measured (calculated) (step S106), and this response is a predetermined number of times set in advance. N, that is, whether or not the number of reception of the response packet is a predetermined number N, for example, the fifth time is determined (step S107).

  If there is no response from the network printer 200 in step S105, or if the response has not reached the predetermined number N in step S107, the process returns to step S104.

  The interface monitor 150 that has determined that the response from the network printer 200 has reached the predetermined number N in step S107 calculates an average value of response times per number N measured (calculated) in step S106 (step S108). Based on the average value of the response times (average response time), the amount of print data to be transmitted, and the packet size determination table 400 set in advance shown in FIG. 4, the packet size (data size) of the packet related to the print data ) Is obtained (step S109).

  Then, the interface monitor 150 sets a packet size for data transmission to the socket interface 160 based on the packet size obtained in step S109 (step S110).

  Thus, packet communication based on the set packet size from the PC 120 to the network printer 200 is started.

  By the way, the response time (average response time) described above is proportional to the traffic status (traffic volume) of the LAN 300. In other words, the shorter the response time (average response time), the less traffic (in other words, the faster the communication speed), while the longer response time (average response time), the more traffic (in other words, communication). It means that the speed is slow).

  The packet size determination table 400 shown in FIG. 4 is a table that is referred to when determining the packet size based on the response time (corresponding to the traffic amount) and the data amount of predetermined data such as print data to be transmitted. .

  That is, the packet size determination table 400 is information in which a plurality of different response time information, different data amount information, and packet size information are associated with each other.

  Such a packet size determination table 400 is stored in a first storage area (for example, ROM) in the storage unit 103 of the PC 100.

  In FIG. 4, T1 to T6 in the “response time item” indicate response time information, and the relationship of “T1 <T2 <T3 <T4 <T5 <T6” is established for these response time information. . The response time information does not indicate a specific response time, but is response time information in a predetermined range from the first response time to the second response time.

  Further, D1 to D6 of “data amount item” indicate data amount information, and the relationship of “D1> D2> D3> D4> D5> D6” is established for these data amount information. The data amount information does not indicate a specific data amount, but is data amount information in a predetermined range from the first data amount to the second data amount.

  Further, α11 to α16, β22 to β26, γ33 to γ36, and ξ66 indicate packet size information, respectively. The packet size information indicates the maximum packet size. When attention is paid to the same data amount, the packet size increases as the response time information moves from “T6” to “T1”. For example, when the data amount is D1, the packet size has a relationship of “α11> α12> α13> α14> α15> α16”.

  Here, determination of the packet size using such a packet size determination table 400 will be described.

  If the data amount of print data to be transmitted corresponds to the data amount D1 of the packet size determination table 400 and the average response time determined in step S108 corresponds to the response time T1 of the packet size determination table 400, the packet to be determined The size is a cell (element) in which the data amount D1 and the response time T2 intersect, that is, α11.

  According to the amount of print data to be transmitted, when the response time is fast, that is, when there is little traffic on the LAN 300 and the communication speed is fast to some extent, the packet size is increased to achieve efficient data transmission. Means.

  If the data amount of the print data to be transmitted corresponds to the data amount D1 of the packet size determination table 400, and the average response time determined in step S108 corresponds to the response time T6 of the packet size determination table 400, it is calculated. The power packet size is a cell (element) at which the data amount D1 and the response time T6 intersect, that is, α16.

  According to the amount of print data to be transmitted, when the response time is slow, that is, when there is a lot of traffic on the LAN 300 and the communication speed is slow, the packet size is reduced to achieve efficient data transmission. means.

  Further, when the data amount of print data to be transmitted corresponds to the data amount D3 of the packet size determination table 400, and the average response time determined in step S108 corresponds to the response time T2 of the packet size determination table 400, it is determined. The power packet size is γ33 which is the maximum packet size in the data amount D3 because there is no cell where the data amount D3 and the response time T2 intersect.

  Note that, as described above, the packet size determination table 400 can be said to be a table in which the degree of congestion (traffic) of lines on the LAN 300 is defined in advance.

  As described above, the packet size can be determined based on the response time (average response time) corresponding to the traffic amount of the LAN 300 and the data amount of the print data to be transmitted to the network printer 200, and based on this packet size. Optimal data communication using packets can be performed.

  In addition, since efficient data communication can be realized, it is possible to reduce the time related to data transfer among the time during which the network printer 200 processes a print job, thereby reducing the print processing time in the network printer 200. It can be shortened.

  Next, the response time (average response time) calculation process of the network print system 1 will be described with reference to FIG.

  FIG. 5 is a sequence showing a processing procedure of response time (average response time) calculation processing according to ICMP of the network print system 1.

  In the following description, an ICMP packet transmitted from the PC 100 is referred to as a “transmission ICMP packet”, and an IP packet including the transmission ICMP packet is referred to as a “transmission IP packet”. Further, an ICMP packet for response to a transmission ICMP packet transmitted from the network printer 200 is referred to as a “response ICMP packet”, and an IP packet including the response ICMP packet is referred to as a “response IP packet”.

  The interface monitor 150 sets a message for confirming whether or not communication between network devices (between the PC 100 and the network printer 200) is established, for example, an echo request (“Echo Request”) in the ICMP packet.

  That is, “8” is set in the “type” field of the ICMP message in the ICMP packet format described above. This “type = 8” indicates an echo request and a message for investigation (“Query message”).

  The interface monitor 150 transmits a transmission IP packet including such a transmission ICMP packet toward the NIC 220 mounted on the network printer 200 (survey target device) (S201).

  When the network printer 200 receives a transmission IP packet including a transmission ICMP packet in which an echo request (“Echo Request”) is set, the interface monitor 240 of the NIC 220 reads the transmission ICMP packet (echo request (“Echo request (“ Echo request ”) in the transmission IP packet). Request ”) refers to the set), and in order to respond to this echo request, when the printer is operating normally, a message indicating that it is operating normally, for example, an echo reply (Echo Reply) is sent to the ICMP packet. Set to.

  That is, “0” is set in the “type” field of the ICMP message. This “type = 0” indicates an echo reply (Echo Reply) and a message for a normal response (“Query message”).

  Then, the interface monitor 240 returns a response IP packet including the response ICMP packet in which such a value is set, to the interface monitor 150 of the PC 100 (S202).

  Next, the interface monitor 150 of the PC 100 sets a time stamp request (“Timestamp Request”) for returning the arrival time to the network printer 200 in the ICMP packet in order to measure the response time.

  That is, “13” is set in the “type” field of the ICMP message in the ICMP packet format described above. In this case, a time at which the transmission source host, that is, the PC 100 transmits the packet, is described in a predetermined field (“Originate Timestamp” field) of the ICMP packet.

  “Type = 13” indicates a time stamp request and indicates a message for investigation (“Query message”).

  Then, the interface monitor 150 transmits a transmission IP packet including a transmission ICMP packet in which such a value is set to the NIC 220 mounted on the network printer 200 (S203).

  When the network printer 200 receives the transmission IP packet including the transmission ICMP packet in which the time stamp request (“Timestamp Request”) is set, the interface monitor 240 of the NIC 220 transmits the transmission ICMP packet (time stamp request ( “Timestamp Request”) refers to the set), and in order to respond to this time stamp request, the source host, that is, the PC 100, returns a time stamp response (“Timestamp Reply”) that returns the arrival time in order to measure the response time. Set in ICMP packet.

  That is, “14” is set in the “type” field of the ICMP message. This “type = 14” indicates a time stamp response and a message for a normal response (“Query message”). In this case, a time (arrival time) when the destination host, that is, the network printer 200 receives the packet is described in a predetermined field (“Receive Timestamp” field) of the ICMP packet.

  Then, the interface monitor 240 returns a response IP packet including the response ICMP packet in which such a value is set to the interface monitor 150 of the PC 100 (S204).

  Then, the interface monitor 150 of the PC 100 that has received the response IP packet including the response ICMP packet in which the time stamp response (“Timestamp Reply”) is set, transmits the response IP packet to the network printer 200 from the time when the network printer 200 receives the response IP packet. The response time (communication time) up to the time when the response IP packet is received is measured (calculated) (S205).

  Then, the same processing as the processing of S203 to S205 is repeated a predetermined number of times N. Here, when the N-th processing is executed a predetermined number of times (S206 to S208), the interface monitor 150 of the PC 100 calculates an average value (average response time) of a plurality of (N) response times already obtained ( S209).

  Next, the interface monitor 150 obtains the packet size of the packet related to the print data based on the calculated average response time, the amount of print data to be transmitted, and the packet size determination table 400 (see FIG. 4). Based on the obtained packet size, a packet size for data transmission is set to the socket interface 160 (S210).

  Thereby, packet communication based on the set packet size from the PC 100 to the network printer 200 is started (S211).

  Next, packet size correction processing of the network print system 1 will be described with reference to FIG.

  FIG. 6 is a sequence showing a processing procedure of the packet size correction processing. In FIG. 6, the display of the IP packet and the ICMP packet is omitted.

  First, processing similar to S201 to S209 of the processing procedure shown in FIG. 5 is executed (S301 to 306). In this example, the time stamp request is transmitted once, but it may be transmitted a plurality of times as in the example shown in FIG.

  Here, the data amount of print data to be transmitted corresponds to the data amount D1 of the packet size determination table 400, and the average response time obtained in step S305 corresponds to the response time T1 of the packet size determination table 400. To do. In this case, the packet size obtained in S306 is α11.

  Then, a transmission IP packet including print data based on the packet size α11 is transmitted from the PC 100 to the network printer 200 (S307). At this time, the interface monitor 150 recognizes the time (transmission time) when the transmission IP packet including the print data is transmitted.

  In the network printer 200, when the interface monitor 240 normally receives the transmission IP packet from the PC 100, the interface monitor 240 transmits a response IP packet including an affirmative acknowledgment (ACK) to the transmission IP packet to the PC 100 (S308).

  In the PC 100, the interface monitor 150 receives a positive acknowledgment (ACK) reception time for the print data from the print data transmission time based on the time when the response IP packet including the ACK is received (reception time) and the transmission time. Time (response time) is calculated (measured) (S309).

  Similarly, a transmission IP packet including print data based on the packet size α11 is transmitted from the PC 100 to the network printer 200 (S310), and a response IP packet including an affirmative acknowledgment (ACK) for the transmission packet. Is transmitted from the network printer 200 to the PC 100 (S311).

  In the PC 100, the interface monitor 150 determines the time from the transmission time of the print data (that is, the transmission IP packet) to the reception time of the ACK (that is, the response IP packet) for the print data (the transmission IP packet), as in the process of S309. (Response time) is calculated (measured) (S312).

  Then, the interface monitor 150 calculates the average value (average response time) of the plurality of response times obtained as described above (S313), and based on the calculated average response time, the packet determined in S306 above. The size is corrected, and the packet size for data transmission is set to the socket interface 160 based on the corrected packet size (S314).

  In the process of step S314, the obtained average response time corresponds to the response time T3 of the packet size determination table 400. The data amount of print data to be transmitted corresponds to the data amount D1 of the packet size determination table 400 as described above. Therefore, the packet size α13 is obtained based on the response time T3 and the data amount D1.

  The interface monitor 150 sets a packet size for data transmission to the socket interface 160 based on the obtained packet size α13. That is, the packet size is corrected from α11 to α13.

  When the corrected packet size α13 corrected as described above is set for the socket interface 160, a transmission IP packet including print data based on the packet size α13 is directed from the PC 100 to the network printer 200. Is transmitted (S315).

  When the socket interface 160 of the network printer 200 normally receives the transmission IP packet from the PC 100, the socket interface 160 transmits a response IP packet including an affirmative acknowledgment (ACK) to the PC 100 (S316).

  In the first embodiment, as shown in the correction processing procedure shown in FIG. 6, an average response time for a plurality of IP packets (print data) is calculated, and the average response time and print data data to be transmitted are calculated. The packet size is corrected based on the amount, but the present invention is not limited to this, and based on the response time required for each IP packet (print data) and the data amount of the print data to be transmitted. The packet size may be corrected.

  In the first embodiment, when obtaining the packet size, the data amount of the print data to be transmitted is the same. However, the present invention is not limited to this and may be as follows. .

  That is, in the process of step S314 of the process procedure shown in FIG. 6, the average response time obtained corresponds to the response time T3 of the packet size determination table 400. Since the print data to be transmitted is untransmitted print data, the data amount of the untransmitted print data corresponds to the data amount D2 of the packet size determination table 400. Then, the packet size β23 is obtained based on the response time T3 and the data amount D2.

  In the first embodiment, the response IP packet corresponding to the time stamp response to the transmission IP packet is transmitted from the transmission time of the transmission IP packet corresponding to the time stamp request, as shown in the processing procedure of FIGS. Although the response time (communication time) until the reception time is obtained, the present invention is not limited to this, and may be as follows.

  That is, the interface monitor 150 performs the transmission from the transmission time of the transmission IP packet corresponding to the time stamp request to the reception time included in the response ICMP in the response IP packet corresponding to the time stamp response to the transmission IP packet, that is, the time stamp request. Calculate the communication time (arrival time). The reception time (arrival time) can be known by referring to the reception time (arrival time) described in the “Receive Timestamp” field of the ICMP. The packet size is determined based on the arrival time, the print data to be transmitted, and the packet size determination table.

  As described above, the packet size can be determined based on the response time (average response time) corresponding to the traffic amount of the LAN 300 and the data amount of print data to be transmitted to the network printer 200. Further, the packet size already determined based on the response time corresponding to the traffic amount of the LAN 300 acquired during execution of the print job by the network printer 200 and the data amount of the print data to be transmitted to the network printer 200 can be corrected. it can.

  That is, the packet size determined according to the response time corresponding to the dynamically changing traffic amount of the LAN 300 is changed to the dynamically changing traffic amount of the LAN 300 periodically acquired in the communication processing of the packet including the print data. Since correction can be made based on the corresponding response time and the amount of print data to be transmitted, optimal data communication can be performed.

  Further, even when the traffic amount of the LAN 300 dynamically changes during the processing of the print job by the network printer 200, efficient data communication can be realized. Among the processing time, the time for data transfer can be greatly shortened, and the print processing time in the network printer 200 can be shortened.

  (Embodiment 2)

  Next, the network print system according to the second embodiment will be described.

  The network print system according to the second embodiment has the same configuration as the overall configuration of the network print system according to the first embodiment shown in FIG. The protocol stack of the network print system has the same configuration as the protocol stack of the first embodiment shown in FIG.

  In this network print system, the packet size of a packet related to the print data is determined based on the amount of print data to be transmitted and the load status of the network printer.

  The network print system according to the second embodiment is basically the same as the first embodiment in the configuration and function as described above, but there are some differences. Next, the differences will be described.

  In the PC 100, the interface monitor 150 having the function of the data size determining means has the following functions (5) to (7) in addition to the functions (1) to (4) in the first embodiment. Have.

  (5) Inquire the network printer 200 about the load status, acquire information indicating the load status returned from the network printer 200 as a result of the inquiry, and obtain the information indicating the acquired load status and a predetermined print to be transmitted. Based on the data amount of the data, the packet size of the packet related to the predetermined print data is determined.

  (6) While the network printer 200 is executing the printing process for the print data from the PC 100, the network printer 200 is inquired about the load state, and information indicating the load state returned from the network printer 200 as a result of the inquiry. The acquired packet size is corrected based on the acquired information indicating the load state and the data amount of predetermined print data to be transmitted.

  (7) Based on the data amount of predetermined print data to be transmitted, the traffic amount on the LAN 300, and the load state of the network printer 200, the packet size of the packet related to the predetermined print data is determined or corrected.

  In the network printer 200, when the printer FW 210 receives an inquiry about the load status from the PC 100, the load status notifying unit returns information indicating the print processing status of the network printer to the PC 100 as a result of the inquiry. It has a function.

  In addition, when the printer FW 210 having the function of the load status notification unit receives an inquiry about the load status while the print processing for the print data included in the packet received from the PC 100 is being executed, It has a function of returning information indicating the data size of receivable data to the PC 100 as a result of the inquiry.

  Next, a print job start process by the interface monitor 150 of the PC 100 of the network print system will be described with reference to FIG.

  First, the interface monitor 150 performs the same processing as steps S101 to S103 of the processing procedure shown in FIG. 3 (steps S401 to S403).

  Next, when the interface monitor 150 that has determined that the connection is successful in step S303 instructs the socket interface 160 to transmit a dummy packet that indicates an inquiry about the load state, the socket interface 160 follows the instruction of the interface monitor 150. For example, a 64-byte dummy packet (inquiry regarding the load state) is sent to the network printer 200 via the LAN 300 (step S404).

  When the dummy packet is transmitted to the network printer 200 through the socket interface 160 in step S404, the interface monitor 150 waits for a response from the network printer 200 through the socket interface 160.

  At this time, if the printer FW 210 of the network printer 200 is processing a print job from a host computer (PC) other than the PC 100 that issued the connection request, the value of the window size (data window size) is “ A response packet set to “0” is returned to the PC 100 that issued the connection request. In this case, since the network printer 200 is in a busy state, it cannot accept print jobs from other PCs including the PC 100.

  On the other hand, when the print job of the PC 100 that issued the connection request can be processed, the window size of the response packet is a receivable buffer size.

  This window size, ie, the receivable buffer size, is information indicating the print processing status as a result of the inquiry regarding the load state, and is also information indicating the data size of receivable data.

  The PC 100 (the interface monitor 150) recognizes the load condition in the printing process of the network printer 200 by repeating the inquiry about the load state even during the printing process by the network printer 200 (the printing unit 202). Can do.

  By the way, when the dummy packet is sent to the network printer 200 as described above, the interface monitor 150 determines whether or not there is a response packet (response) from the network printer 200 (the printer FW 210). (Step S405).

  Next, when the interface monitor 150 determines in step S405 that there is a response packet returned from the network printer 200 (the printer FW 210), that is, when the response packet is received, the value of the window size of the response packet. For example, in the third storage area (work area) of the storage unit 103 (step S406), and the current response is a predetermined number of times, that is, the response packet is received a predetermined number N, For example, it is determined whether it is the fifth time (step S407).

  If there is no response from the network printer 200 in step S405, or if the response has not reached the predetermined number N in step S407, the process returns to step S404.

  When the interface monitor 150 determines that the response (response packet) from the network printer 200 has reached the predetermined number N in step S407, the average value (average window) of the window sizes related to the plurality of response packets temporarily stored in step S406. (Size) is calculated (step S408), and the packet size (data size) of the packet related to the print data is obtained based on the average window size and the amount of print data to be transmitted (step S409).

  In this case, the packet size can be set to the maximum packet size by adopting the average window size, but the average window size is appropriately divided into a plurality according to the amount of print data to be transmitted. The size is preferable.

  Then, the interface monitor 150 sets a packet size for data transmission to the socket interface 160 based on the packet size obtained in step S409 (step S410).

  As described above, the packet size can be determined based on the receivable buffer size of the network printer 200 and the amount of print data to be transmitted to the network printer 200, and the optimum data by the packet based on this packet size. Communication can be carried out.

  In addition, since efficient data communication can be realized, it is possible to reduce the time related to data transfer among the time during which the network printer 200 processes a print job, thereby reducing the print processing time in the network printer 200. It can be shortened.

  Next, packet size correction processing of the network print system 1 will be described with reference to FIG.

  FIG. 8 is a sequence showing the processing procedure of the packet size correction processing.

  First, as described above, when the socket interface 160 of the PC 100 sends, for example, a 64-byte dummy packet (inquiry about load status) to the network printer 200 via the LAN 300 in accordance with the instruction of the interface monitor 150 (S501), the network printer When the printer FW 210 of 200 normally receives the dummy packet (IP packet), the printer FW 210 transmits a response packet (IP packet) including a window size in which a predetermined value is set to the PC 100 (S502).

  At this time, the interface monitor 150 of the PC 100 temporarily stores the window size value in the received response packet in the storage unit 103.

  Similarly, the processes of S501 and S502 are repeated until the transmitted dummy packet reaches a predetermined value set in advance (S503 and S504).

  When the dummy packet transmitted from the socket interface 160 reaches a predetermined value set in advance, the interface monitor 150 calculates an average value (average value) of window size values for a predetermined value (plurality) temporarily stored. (Window size) is obtained (S505), and the packet size of the packet relating to the print data is obtained based on the average window size and the amount of print data to be transmitted.

  Next, the interface monitor 150 sets a packet size for data transmission to the socket interface 160 based on the obtained packet size (step S506).

  Here, it is assumed that the obtained average window size is a value “WS1”, and this average window size WS1 is defined as a packet size PS1. A packet (IP packet) including print data based on the packet size PS1 is transmitted from the PC 100 to the network printer 200 (S507).

  If the network printer 200 normally receives the packet, the network printer 200 transmits a packet (IP packet) including an affirmative acknowledgment (ACK) to the PC 100 (S508).

  Similar processing is performed for a plurality of packets. That is, a transmission process of a packet (packet size PS1) including print data by the PC 100 is performed (S509), and a transmission process of a packet including a positive acknowledgment (ACK) for the received packet is performed by the network printer 200 (S509). S510).

  Assume that there is untransmitted print data in the PC 100 when a plurality of packets including print data is transmitted in this way.

  After S510 ends, in the PC 100, the interface monitor 150 transmits a dummy packet to the network printer 200 in order to know the load state of the network printer 200 without transmitting a packet including the next print data ( S511). Upon receiving this dummy packet, the printer FW 210 of the network printer 200 transmits a response packet including a window size in which a predetermined value is set to the PC 100 (S512).

  Here, the dummy packet is transmitted only once, but may be transmitted a plurality of times.

  In the PC 100, the interface monitor 150 obtains the value of one temporarily saved window size or obtains the average value (average window size) of a plurality of temporarily saved window sizes (S513). ).

  Next, the interface monitor 150 corrects the already determined packet size based on the acquired window size (or the obtained average window size) and the amount of print data to be transmitted, and the corrected packet. Based on the size, a packet size for data transmission is set to the socket interface 160 (S514).

  In the process of step S514, the acquired window size is assumed to be a value “WS3”, and this window size WS3 is defined as a packet size PS3. Here, it is assumed that the relationship of “WS3 <WS1” is established for the window size. Therefore, the relationship of “PS3 <PS1” is also established for the packet size.

  Then, a packet (IP packet) including print data based on a packet size PS3 smaller than the packet size PS1 before correction is transmitted from the PC 100 to the network printer 200 (S515). In this case, the packet size is corrected from PS1 to PS3.

  As described above, the packet size can be determined based on the receivable buffer size of the network printer 200 and the amount of print data to be transmitted. Further, it is possible to correct the packet size already determined based on the receivable buffer size of the network printer 200 acquired during execution of the print job by the network printer 200 and the amount of print data to be transmitted.

  That is, the operation of the network printer 200 that periodically acquires the packet size determined according to the dynamically changing print processing status (receivable buffer size) of the network printer 200 in the transmission processing of the packet including the print data. Since the correction can be made based on the print processing status (receivable buffer size) and the amount of print data to be transmitted, optimum data communication can be performed.

  In addition, during the processing of the print job by the network printer 200, efficient data communication can be realized by transmitting a packet corresponding to the receivable buffer size that dynamically changes in the network printer 200. Of the time during which the network printer 200 processes a print job, the time for data transfer can be greatly reduced, and the time required for printing by the network printer 200 can be shortened.

  Next, another packet size correction process of the network print system 1 will be described with reference to FIG.

  FIG. 9 is a sequence showing a processing procedure of another packet size correction process.

  First, the same processing as S501 to S506 of the processing procedure shown in FIG. 8 is performed (S601 to S606). Also in this case, in S606, the obtained average window size WS1 is defined as the packet size PS1.

  Then, a packet (IP packet) including print data based on the packet size PS1 is transmitted from the PC 100 to the network printer 200 (S607). At this time, the interface monitor 150 recognizes the time (transmission time) when the packet including the print data is transmitted.

  When the network printer 200 normally receives a packet including the print data, the network printer 200 transmits a packet (IP packet) including an affirmative acknowledgment (ACK) to the PC 100 (S608).

  In the PC 100, the interface monitor 150 determines a positive acknowledgment (ACK) regarding the print data from the transmission time of the print data based on the time point (reception time) when the packet including the positive acknowledgment (ACK) is received and the transmission time. The response time until the reception time is calculated (measured) (S609).

  Similarly, a packet (IP packet) including print data based on the packet size PS1 is transmitted from the PC 100 to the network printer 200 (S610), and a packet including an affirmative acknowledgment (ACK) for this packet ( IP packet) is transmitted from the network printer 200 to the PC 100 (S611).

  In the PC 100, the interface monitor 150 calculates (measures) the time (response time) from the print data transmission time to the ACK reception time for the print data (S612), similar to the processing of S609 described above. An average value (average response time) of the plurality of response times obtained in this way is calculated (S613).

  Next, the interface monitor 150 corrects the packet size determined in S606 based on the calculated average response time and uses the corrected packet size to transmit data to the socket interface 160. The packet size is set (S614).

  In the process of step S614, it is assumed that the obtained average response time corresponds to the response time T3 of the packet size determination table 400 shown in FIG. In addition, the data amount of the print data signal to be transmitted (untransmitted print data) corresponds to the data amount D2 of the packet size determination table 400. Therefore, the packet size β23 is obtained based on the response time T3 and the data amount D2. Here, the packet size is assumed to be β23 = PS3 <PS1.

  The interface monitor 150 sets a packet size for data transmission to the socket interface 160 based on the obtained packet size PS3 (β23). That is, the packet size is corrected from PS1 to PS3.

  When the corrected packet size PS3 corrected as described above is set for the socket interface 160, a packet (IP packet) including print data based on the packet size PS3 is transmitted from the PC 100 to the network printer 200. (S615).

  As described above, the packet size can be determined based on the receivable buffer size of the network printer 200 and the amount of print data to be transmitted. Further, it is possible to correct the packet size already determined based on the response time corresponding to the traffic amount of the LAN 300 acquired during execution of the print job by the network printer 200 and the data amount of the print data to be transmitted.

  That is, the packet size determined in accordance with the dynamically changing print processing status (receivable buffer size) of the network printer 200 is dynamically obtained from the LAN 300 periodically acquired in the transmission processing of packets including print data. Since the correction can be made based on the response time corresponding to the changing traffic amount, the data amount of the print data to be transmitted, and the packet size determination table 400, optimum data communication can be performed.

  Further, even when the traffic of the LAN 300 dynamically changes during the processing of the print job by the network printer 200, efficient data communication can be realized, so that the network printer 200 can execute the print job. Of the processing time, the time for data transfer can be greatly shortened, and the printing processing time in the network printer 200 can be shortened.

  The present invention can be applied to a printing system in which an image forming apparatus having a copying function and a printing function (an image forming apparatus as a so-called multifunction machine) and a transmission source device such as a host computer are connected via a communication line.

1 is a configuration diagram illustrating an overall configuration of a network print system according to a first embodiment. 1 is a configuration diagram illustrating a configuration of a protocol stack of a network print system according to a first embodiment. 4 is a flowchart illustrating a processing procedure of print job start processing by an interface monitor of a host computer according to the first embodiment. 6 is a diagram showing an example of a packet size determination table according to Embodiment 1. FIG. 4 is a sequence showing a processing procedure of response time calculation processing of the network print system according to the first embodiment. 6 is a sequence showing a processing procedure of packet size correction processing of the network print system according to the first embodiment. 10 is a flowchart illustrating a processing procedure of print job start processing by an interface monitor of a host computer according to the second embodiment. 10 is a sequence showing a processing procedure of packet size correction processing of the network print system according to the second embodiment. 10 is a sequence showing a processing procedure of another packet size correction process of the network print system according to the second embodiment.

Explanation of symbols

1 Network Print System 100 Host Computer (Sender Device)
101 Display Unit 102 Input Unit 103 Storage Unit (Storage Unit)
104 communication interface 105 control unit (packet size determining means)
110 Application 120 Operating system 130 Printer driver 140 Print spooler 150 Interface monitor (packet size determining means)
160 Socket interface 200 Network printer (printing device)
201 Storage Unit 202 Printing Unit 203 Communication Interface 204 Control Unit (Load Status Notification Unit)
210 Printer firmware (load status notification means)
220 NIC (network interface card)
230 NIC interface 240 Interface monitor (reception time notification means)
250 Socket interface 300 LAN (communication line)
400 packet size determination table (storage means)

Claims (14)

A transmission source device that transmits print data and a printing device that executes print processing based on the print data transmitted from the transmission source device are connected via a communication line, and data is transmitted between these devices according to a predetermined communication protocol. A printing system that performs transmission and reception,
The transmission source device is:
Based on the data amount of the predetermined print data to be transmitted to the printing device and the information on at least one of the traffic amount on the communication line and the load state of the printing device, the packet of the predetermined print data A packet size determining means for determining the packet size;
Have
Transmitting a packet based on the packet size determined by the packet size determining means to the printing apparatus;
A printing system characterized by that. The packet size determining means includes
The reception time when receiving a message indicating the reception time of the predetermined packet transmitted from the printing apparatus that has received the predetermined packet from the time when the predetermined packet not including print data is transmitted to the printing apparatus A packet size of the packet related to the predetermined print data is determined based on the communication time until and the data amount of the predetermined print data.
The printing system according to claim 1. Embodiment 1
The packet size determining means includes
A communication time from a time when a predetermined packet not including print data is transmitted to the printing apparatus to a time when an indication of an acknowledgment transmitted from the printing apparatus that has received the predetermined packet is received; Based on the data amount of the print data, the packet size of the packet related to the predetermined print data is determined.
The printing system according to claim 1. The transmission source device is:
Storage means for storing information in which a plurality of different communication time information, a plurality of different data amount information, and a plurality of packet size information are associated with each other;
The packet size determining means includes
Determining the packet size of the packet related to the predetermined print data based on the communication time obtained by transmitting the predetermined packet, the data amount of the predetermined print data, and the storage content of the storage unit;
The printing system according to claim 2 or 3, wherein The packet size determining means includes
Inquires the load status to the printing device, acquires information indicating the load status returned from the printing device as a result of the inquiry, information indicating the acquired load status and the data amount of the predetermined print data, A packet size of the packet related to the predetermined print data is determined based on
The printing system according to any one of claims 1 to 4, wherein: The printing apparatus includes:
A reception time notifying unit that, when receiving the predetermined packet transmitted from the transmission source device, indicates to the packet size determining unit that the reception time when the predetermined packet is received is indicated;
The printing system according to claim 1, further comprising: The printing apparatus includes:
A load status notifying unit that, when receiving an inquiry about the load status from the transmission source device, returns information indicating the print processing status of the printing device to the transmission source device as a result of the query;
The printing system according to claim 1, further comprising: The load state notification means includes
Information indicating the data size of receivable data when there is an inquiry about the load state while print processing is being executed for print data included in a packet from the transmission source device that has already been received As a result of the inquiry to the transmission source device,
The printing system according to claim 7. The packet size determining means includes
Response time from the time when a packet including print data is transmitted based on the already determined packet size to the time when a message indicating an acknowledgment transmitted from the printing apparatus that has received the packet is received, and the print to be transmitted Correct the already determined packet size based on the amount of data,
The printing system according to any one of claims 1 to 8, wherein: Flow control is not performed in data communication between the transmission source device and the print data.
The printing system according to any one of claims 1 to 9, wherein: A printing device that is connected to a transmission source device that transmits print data via a communication line and performs data communication with the transmission source device according to a predetermined communication protocol that does not have a flow control function,
A load status notifying unit that, when receiving an inquiry about the load status from the transmission source device, returns information indicating the print processing status of the printing device to the transmission source device as a result of the query;
A printing apparatus comprising: The load state notification means includes
If there is an inquiry about the load status while print processing is being performed on print data included in a packet related to predetermined print data from the transmission source device that has already been received, Returning information indicating the data size to the transmission source device as a result of the inquiry;
The printing apparatus according to claim 11. When receiving a predetermined packet transmitted from the transmission source apparatus and not including print data, the apparatus further comprises reception time notifying means for transmitting to the transmission source apparatus that the reception time when the predetermined packet is received is indicated. The
The printing apparatus according to claim 11 or 12, characterized in that: A data communication method of a printing system in which a transmission source device transmits a packet related to predetermined print data to a printing device through a communication line,
Without performing flow control related to data communication between the transmission source device and the printing device,
Before the transmission source device transmits a packet including print data, at least one of the load state of the printing device and the traffic amount on the communication line acquired from the printing device and the predetermined print data A packet size is determined based on the data amount and a packet including print data is transmitted to the printing apparatus based on the determined packet size.
A data communication method for a printing system.

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