JP2007004225A - Printer for processing two or more print jobs - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize smooth distributed print processing by dividing a print job into two or more packets. <P>SOLUTION: This printer PRT is provided with a TCP/IP part 10 as a communication part, a print job receiving part 50, and a printer body PRB as a print executing part. This TCP/IP part 10 performs communication using a connection type protocol. The print job receiving part 50 receives a print job through connection. The number of print jobs which can be received by a print job receiving part 50 in parallel is m (m is a natural number). The printer body PRB executes print processing in parallel for the received print job. The number of connection which is simultaneously held by the TCP/IP part 10 is set to m or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printing apparatus capable of processing a plurality of print jobs, and more particularly to a printing apparatus used as a distribution destination for distributed printing.

  There is known a distributed printing system in which a print control apparatus connected to a plurality of printing apparatuses distributes a print job to the plurality of printing apparatuses (for example, Patent Document 1). In the above technique, printing of a plurality of copies can be completed in a short time by appropriately distributing the number of copies to be printed to a plurality of printing apparatuses and performing printing in parallel.

JP 2001-273113 A JP 2001-1000096 A JP-A-6-214920

  By the way, in such a distributed printing system, there is a method of distributing a print job by dividing it into a plurality of packets. In this distribution method, a print job is distributed by repeatedly executing a process of distributing packets to a plurality of destination printers for each packet. In this way, for example, when a print job is received from a computer as a client via a network and the received print job is distributed to a plurality of printing devices, the buffer capacity of the print control device is small and the client Even when all print jobs cannot be received from the computer at once, the print control apparatus can distribute the print jobs.

  However, in the above prior art, when the above-described dispersion method is used, there is a possibility that smooth dispersion printing may be hindered depending on the printing apparatus that is the distribution destination. For example, if a printing device can simultaneously hold a plurality of connections for receiving a print job, but can only process one print job at a time, the printing device is typically connected from a previously established connection. The print job is received in order, and after the processing of the print job is completed, the print job from the next connection is received. When the above-described distribution method is used with such a printing apparatus as a distribution destination, when a packet is transmitted to a connection that is in a waiting state, distribution processing must be stopped until the packet is received. .

  In particular, when a print job is distributed by the above-described distribution method using a plurality of printing apparatuses shared by a plurality of print control apparatuses as a distribution destination, there is a possibility that the distribution processing may be completely stopped.

  SUMMARY An advantage of some aspects of the invention is to realize a smooth distributed printing process.

  In order to solve at least a part of the above problems, the present invention provides a printing apparatus. A printing apparatus according to the present invention is a communication unit that performs communication using a connection-type protocol, and includes a communication unit that holds a connection for the communication, and a print job reception unit that receives a print job via the connection A number of print jobs that can be received in parallel is m (m is a natural number), a print execution unit that executes print processing in parallel for the received print jobs, The number of connections simultaneously held by the communication unit is set to m or less.

  According to the printing apparatus of the present invention, since the number of connections exceeding the number m of print jobs that can be received in parallel is not held, the device that transmits the print job through the connection is put in a standby state. There is nothing. In particular, when used as a distribution destination printing apparatus, the distributed printing process can proceed smoothly.

  The printing apparatus according to the present invention divides the print job into a plurality of packets, and repeatedly executes packet distribution for transmitting the packets to two or more distribution destination printing apparatuses for each of the divided packets. Accordingly, the print job may be connected to a print control apparatus capable of transmitting the print job to two or more distribution destination printing apparatuses, and may be used as the distribution destination printing apparatus. By so doing, it is possible to prevent a deadlock that may occur in distributed printing processing by such a printing control apparatus.

  In the printing apparatus according to the present invention, the print execution unit is an interpretation unit that interprets the received print job and issues a print request. The interpretation unit executes the interpretation process for the m print jobs. May be provided in parallel, and a printing unit that outputs a print result of the print job based on the issued print request. In this way, since print jobs received in parallel are interpreted in parallel, a smoother printing process can be realized.

  In the printing apparatus according to the present invention, the printing unit may output a plurality of print job print results by repeatedly outputting a predetermined number of print results of each print job. In this way, even if there are fewer than m printing units, the printing process can be performed in parallel for a plurality of print jobs.

  The printing apparatus according to the present invention may further include a sorter mechanism that stores the print result output by the printing unit in a plurality of storage units for each print job. In this case, the number m of print jobs that can be received in parallel may be the number of storage units included in the sorter mechanism. In this way, it is possible to avoid the inconvenience of mixing print results of print jobs processed in parallel.

  In the printing apparatus according to the present invention, the number m of print jobs that can be received in parallel may vary depending on the state of the printing apparatus. For example, the number m of print jobs that can be received in parallel may be the number of storage units that are capable of storing print results among the storage units of the sorter mechanism.

  In the printing apparatus according to the present invention, m printing units may be provided. In this way, since the printing unit can be used for each receivable print job, a plurality of print jobs can be smoothly advanced in parallel.

  In addition to the configuration as the printing apparatus described above, the present invention can be realized as a method invention such as a printing method thereof. Further, aspects as a computer program for constructing those methods and apparatuses, aspects as a recording medium recording such a computer program, data signals embodied in a carrier wave including the computer program, etc. It can also be realized in various ways.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a printing apparatus according to the invention will be described based on examples with reference to the drawings.

A. Example:
・ Configuration of distributed printing system:
With reference to FIGS. 1 and 2, the configuration of the distributed printing system in the embodiment of the present invention will be described. FIG. 1 is an explanatory diagram showing a schematic configuration of a distributed printing system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating an internal configuration of each device included in the distributed printing system according to the embodiment.

  As shown in FIG. 1, the distributed printing system includes a plurality of computers as clients (hereinafter simply referred to as clients) CLa and CLb, and a plurality of printers PRT1 to PRT4. The clients CLa and CLb and the printers PRT1 to PRT4 are connected to each other via a local area network (LAN). Since communication between devices is performed using the TCP / IP protocol, each device is assigned an IP address. For convenience of explanation, it is assumed that IP addresses “IPa” and “IPb” are set for the clients CLa and CLb, and IP addresses “IP1” to “IP4” are set for the printers PRT1 to PRT4, respectively. Strictly speaking, these IP addresses are not set in the clients CLa and CLb and the printers PRT1 to PRT4 themselves, but are nodes when viewed from the TCP / IP network (that is, specifically, For example, a network board connected to a network to perform TCP / IP communication).

  Among these printers, the custom network boards 100 are respectively attached to the printers PRT1 and PRT4. The custom network board 100 has a distributed print control function for distributing print jobs received from the clients CLa and CLb to other printers and executing distributed printing, and corresponds to the print control device in the claims. . A standard network board 200 is attached to each of the printers PRT2 and PRT3.

  In FIG. 1, arrows indicated by solid lines conceptually indicate that a print job is transmitted from the client CLa to the custom network board 100 of the printer PRT1, and the print jobs are distributed from the custom network board 100 of the printer PRT1 to the printers PRT1 to PRT4. Is shown. Arrows indicated by broken lines conceptually show that a print job is transmitted from the client CLb to the custom network board 100 of the printer PRT4, and the print jobs are distributed from the custom network board 100 of the printer PRT4 to the printers PRT1 to PRT4. Yes. As described above, the printers PRT1 to PRT4 can be distributed to any of the custom network boards 100 of the printer PRT1 and the printer PRT2. In the following, when it is not necessary to distinguish between the printers PRT1 to PRT4, the numerals at the end of the reference numerals are omitted and are also referred to as printers PRT. In addition, when it is not necessary to distinguish between the clients CLa and CLb, the lowercase alphabetic characters are omitted, and the client CLa is also referred to as a client CL.

  As shown in FIG. 2, the printer PRT1 includes a printer main body PRB and the custom network board 100 described above. The printer main body PRB includes a central processing unit (CPU) 60, a memory 70, a printer engine 80, and a sorter 85. The CPU 60 functions as a controller that controls the entire printer body PRB. The memory 70 is a memory for temporarily storing a program and data for control by the CPU 60. The printer engine 80 is a mechanism portion that actually performs printing. In this embodiment, the printer engine 80 is a so-called laser type printer engine that forms an image on printing paper by utilizing a phenomenon that toner powder adheres due to static electricity. The sorter 85 includes three paper discharge bins as storage units for storing printed paper (hereinafter referred to as “printed paper”), and print paper sent from the printer engine 80 is selectively selected for each paper discharge bin. It has a mechanism for storing it.

  The CPU 60 reads various programs such as software for controlling the printer main body PRB from the memory 70 and executes them, thereby realizing various control functions in software. Each function may be constructed in hardware. The functions realized by the memory 70 include a print job interpretation unit 90. The print job interpretation unit 90 includes a plurality of sub interpretation units as sub functional blocks. In this embodiment, three sub-interpretation units are provided, which are referred to as a first interpretation unit 91, a second interpretation unit 92, and a third interpretation unit 93, respectively (see FIG. 2). Each of the three interpreters interprets the print job, generates image data, and performs processing (hereinafter also referred to as interpretation processing) for issuing a print request together with the generated image data. These three interpretation units function independently of each other. As a result, the print job interpretation unit 90 can execute three interpretation processes in parallel. The printer engine 80 receives image data and a print request from the print job interpreter 90, and executes printing based on these.

  The custom network board 100 mainly includes a CPU 20 and a memory 30. In addition, although a communication interface for actually performing network communication is also provided, it is omitted for convenience of explanation.

  The CPU 20 reads out and executes programs such as software for executing distributed printing and data communication from the memory 30, thereby realizing each function illustrated in software. Each function may be constructed in hardware.

  The functional blocks realized by the CPU 20 include a TCP / IP unit 10, a distribution control unit 40, and a print job reception unit 50. The TCP / IP unit 10 interprets the TCP / IP protocol and performs communication with the outside mainly via the network. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are protocols that perform transport layer processing in the TCP / IP protocol. TCP is a protocol for realizing highly reliable connection-type communication. On the other hand, UDP is a protocol that realizes high-speed connectionless communication. The TCP / IP unit 10 performs communication of a print job to be described later using TCP, and performs communication by SNMP to be described later using UDP.

  The distribution control unit 40 receives a print job designating distributed printing (hereinafter also referred to as a distributed print job), and distributes the print job to the distribution destination. The processing executed by the distribution control unit 40 will be further described later.

  The print job reception unit 50 includes a plurality of sub reception units as sub functional blocks. In this embodiment, three sub-reception units are provided, which are referred to as a first reception unit 51, a second reception unit 52, and a third reception unit 53, respectively (see FIG. 2). Each of the three receiving units receives a normal print job that does not designate distributed printing (hereinafter referred to as a normal print job) and supplies it to the printer main body PRB. These three receiving units function independently of each other. As a result, the print job receiving unit 50 can receive three print jobs in parallel.

  The memory 30 functions as a reception buffer that temporarily stores a print job received by the print job receiving unit 50 in addition to storing a program for realizing the above-described functions.

  As shown in FIG. 2, the printer PRT2 includes a printer main body PRB and the network board 200 described above. The configuration of the printer main body PRB has the same configuration as that of the printer main body PRB of the printer PRT1 described above. Therefore, the same reference numerals as those of the printer main body PRB of the printer PRT1 are assigned to the respective components, and description thereof is omitted. To do. The network board 200 has components excluding the distributed control unit 40 among the functions of the custom network board 100 described above. That is, the network board 200 includes the TCP / IP unit 10, the print job receiving unit 50, and the memory 30. Since each component of the network board 200 has the same function and configuration as the component of the same name of the custom network board 100, the description thereof is omitted.

  Here, as understood from the above description, the custom network board 100 mounted on the printers PRT1 and PRT4 has all the functions of the network board 200 mounted on the printers PRT2 and PRT3. That is, as seen from the distribution control unit 40 of the network board 200, the printers PRT1 to PRT4 are all equivalent and can all be designated as distribution destination printers in the distributed printing process described later. The distribution control unit 40 can handle the printer PRT1 including the distribution control unit 40 itself and other printers without distinction.

  As shown in FIG. 2, the client CLa includes a TCP / IP unit 13 and a print job transmission unit 12 as functional blocks in addition to the application 11. The TCP / IP unit 13 interprets the TCP / IP protocol and performs communication with the outside mainly via the network. The print job transmission unit 12 generates a print job in response to a print request from the application 11 and transmits the print job generated via the TCP / IP unit 13 to the printer PRT. A distributed print job that designates distributed printing can be transmitted only to the printers PRT1 and PRT4 including the custom network board 100, and a normal print job that does not designate distributed printing is transmitted to any of the printers PRT1 to PRT4. be able to.

  The printer PRT4 has the same configuration as the printer PRT1 described above, and the printer PRT3 has the same configuration as the printer PRT2 described above. The client CLb has the same configuration as the client CLa described above. Detailed description of these will be omitted.

  As can be understood from the above description, the TCP / IP unit 10 in this embodiment is the communication unit in the claims, the printer main body PRB is the print execution unit in the claims, and the printer engine 80 is in the claims. Each corresponds to a printing section.

・ Distributed printing processing:
Next, the distributed printing process will be described in detail with reference to FIGS. FIG. 3 is a conceptual diagram showing the data structure of a print job. FIG. 4 is a flowchart showing a processing routine of distributed printing processing. FIG. 5 is an explanatory diagram illustrating an example of a communication sequence in which a print job is transmitted to a plurality of print job receiving units 50.

  The distributed printing process is a process executed by the distributed control unit 40 included in the CPU 20 of the custom network board 100. The distribution control unit 40 distributes and prints the designated number of copies to the distribution destination printer. When the distribution control unit 40 receives a distributed print job with 100 copies, for example, the distribution control unit 40 transmits normal print jobs with 25 print copies to the printers PRT1 to PRT4, respectively. As a result, 100 copies are printed as the entire distributed printing system.

  The print job is transmitted as communication data in a format according to the TCP / IP protocol. The communication data is divided into a header 400 and a data part 450 as shown in FIG. Among these, the header 400 includes an IP address (source IP address) of a device that is a transmission source of the communication data, a port number (source port number) that identifies software that is a transmission source in the device, The IP address of the device that is the transmission destination of the communication data (transmission destination IP address), and the port number (transmission destination port number) that identifies the software that is the transmission destination in the device. Communication data transmitted from the software of the transmission source device is transmitted to the device having the IP address in accordance with the transmission destination IP address. Further, in the received device, the port of that number is transmitted in accordance with the transmission destination port number. Passed to the waiting software. The data part 450 is a part in which data to be transmitted / received is stored, and in this embodiment, print job data 500 to be described later is stored.

  The print job data 500 includes a job control language part 501 and a page description language part 502 as shown in FIG. The page description language part 502 is a part in which print contents are described using a predetermined page description language. As the page description language, ESC / Page, Postscript, or the like can be used. The job control language unit 501 prints the print contents described in the page description language unit 502, including the number of copies, the print paper size, and the type of page description language used to describe the page description language unit 502. Necessary attributes are described. The job control language unit 501 is described using a predetermined job control language, which is EJL (Epson Job Language) in this embodiment.

  When performing distributed printing, the user changes the setting of the transmission destination port number from the normal “9100” to a specific “59100” in the printer driver in the client (for example, the client CLa (FIG. 1)). That is, in this embodiment, by switching the setting of the port number, normal printing is selected for the normal “9100” and distributed printing is selected for the specific “59100”. The print job receiving unit 50 waits for the port number “9100”. On the other hand, the above-described distributed control unit 40 is waiting at the port number “59100”.

  The distributed printing process will be described step by step with reference to FIG. When the printer on which the custom network board 100 is mounted (for example, the printer PRT1) is in a state of accepting a print job, the distribution control unit 40 stands by until a print job arrives at the port number “59100” (step S102). ).

  When communication data including a print job (distributed print job) specifying “59100” as the destination port number from the client CL arrives at the printer PRT1 (step S102: YES), the TCP / IP unit 10 determines that the port number “59100”. The print job is handed over to the distribution control unit 40 that is on standby. The distribution control unit 40 temporarily stores the first portion (packet P1 described later) of the received print job in the memory 30 (step S104).

  Here, the size of the print job data 500 increases according to the amount of printing per part, whereas the memory 30 has a limited storage area capacity for storing the print job data 500. The print job data 500 is obtained by being divided into data chunks (hereinafter referred to as packets) smaller than the capacity of the storage area. In FIG. 3C, the print job data 500 is divided into packets P1 to P8. When the print job arrives in step S <b> 102 described above, only the packet P <b> 1 is acquired and stored in the memory 30.

  Returning to FIG. 4, the description will be continued. Next, the distribution control unit 40 executes processing for selecting a distribution destination printer (steps S106 to S114). First, the distribution control unit 40 acquires the IP address of a device connected on the network (step S106). For example, the distributed control unit 40 inquires about the IP address of each device connected to the LAN by broadcast to the LAN using SNMP, and acquires the responded IP address. Alternatively, when a distribution destination designation file is set, the distribution control unit 40 refers to the distribution destination designation file and acquires an IP address. In the distribution destination designation file, for example, IP addresses of printers that are to be used as distribution destinations are listed and described. Such a distribution destination designation file is stored in the memory 30 by, for example, connecting a setting computer or the like to the printer PRT1 when the serviceman installs the printer PRT1 and performs initial setting. be able to. Further, it may be installed via a LAN. When such a distribution destination designation file is used, if it is desired to use its own printer PRT1 as the distribution destination, the IP address “IP1” of the self printer PRT1 must also be described in the distribution destination designation file. .

  Next, the distribution control unit 40 acquires information regarding each device to which the acquired IP address is assigned (step S108). Specifically, the distribution control unit 40 uses SNMP to make an inquiry to each device by multicast, and acquires the model name and status as a response to the inquiry.

Based on the acquired model name and status, the distribution control unit 40 searches for a printer that satisfies a predetermined condition from the devices connected to the network, and selects the searched printer as a distribution destination printer (step). S110). In this embodiment, it is assumed that some or all of the above-described printers PRT1 to PRT4 are selected as distribution destination printers. The conditions for selecting a printer as a distribution destination printer are as follows.
1. The same model as the self printer (for example, printer PRT1).
2. The power is turned on.
3. The remaining amount of toner is not less than a predetermined threshold.
4). Be online.
5. The printer is not printing (the printer engine 80 is not being driven).

  The condition for selecting the same printer model as the self-printer PRT1 as a destination printer is that, when performing distributed printing, each destination printer does not perform data conversion of the print job and the like. This is to make it happen. As a result, it is possible to unify the quality of printed matter, for example, the resolution and font, at each distribution destination printer.

  The conditions 2 to 5 are for preventing a printer that cannot be printed immediately from being selected as a distribution destination printer. The online state refers to a normal state that is not a state in which an error such as running out of paper or a paper jam has occurred (offline state).

  Then, the distribution control unit 40 determines whether one or more distribution destination printers have been selected (step S112). When one distribution destination printer is not selected (step S112: NO), the distribution control unit 40 waits for a predetermined period (step S114), and repeats the processing from step S106 to step S112.

  When one or more distribution destination printers are selected (step S112: YES), the distribution control unit 40 receives a print job of the distribution destination printer from the distribution control unit 40 with each selected distribution destination printer. A connection for transmitting a print job to the unit 50 is established (step S116). Specifically, the distribution control unit 40 causes the TCP / IP unit 10 of the custom network board 100 to perform connection establishment processing with the TCP / IP unit 10 of the distribution destination printer. A TCP packet (SYN packet) indicating a first establishment request from the custom network board 100 to the distribution destination printer, a reception confirmation for the first establishment request, and a second establishment request from the distribution destination printer to the custom network board 100 When a TCP packet (ACK / SYN packet) that also serves as a packet and a TCP packet (ACK packet) indicating receipt confirmation for the second establishment request are sequentially exchanged between the two TCP / IP units 10, a connection is established. Is done.

  The distribution control unit 40 transmits a print job to each distribution destination printer via each established connection (step S118). The job control language portion 501 of the print job to be transmitted describes the number of print copies distributed for each distribution destination. The print job to be transmitted is transmitted with the destination port number as “9100”. Here, the transmission of a print job from the distribution control unit 40 to the distribution destination printer (print job receiving unit 50) in the distributed printing process will be further described with reference to FIG. In FIG. 5, the distribution control unit 40 of the printer PRT1 receives a print job from the client CLa, and transmits (distributes) the print job to the print job reception units 50 of the two printers PRT2 and PRT3. Show.

  As described above with reference to FIG. 3C, the print job data 500 is acquired from the client in predetermined packets. For this reason, transmission of a print job from the distribution control unit 40 to the print job reception unit 50 of the distribution destination printer needs to be performed in a plurality of times for each packet. In the example shown in FIG. 5, the print job data 500 divided into eight packets P1 to P8 shown in FIG. 3C is transmitted.

  When the distribution control unit 40 starts transmitting a print job (step S118), first, the packet P1 (the first packet of the print job including the job control language unit 501) stored in the memory 30 is first transferred to the printer PRT2 and the printer. The data is transmitted to the print job receiving unit 50 of PRT3. Hereinafter, such transmission of packets to the print job receiving units 50 of a plurality of distribution destination printers is referred to as packet distribution. In FIG. 5, a set of arrows surrounded by a broken line indicated by a symbol PD corresponds to one packet distribution.

  When the end of the packet distribution PD of the first packet P1 is confirmed, the distribution control unit 40 receives the next packet P2 from the client CLa as shown in FIG. Confirmation of the end of the packet distribution PD is performed by the TCP / IP unit 10 of the transmission source and the transmission destination according to the TCP protocol. The distribution control unit 40 erases the packet P1 stored in the memory 30 and stores the newly received packet P2 in the memory 30. The distribution control unit 40 executes packet distribution PD on the packet P2 stored in the memory 30 in the same manner as the packet P1. By repeating the same processing for the remaining packets P3 to P8 constituting the print job data 500, the entire print job data 500 is finally transmitted to the print job receiving units 50 of the printer PRT2 and the printer PRT3, respectively. The

-Processing in the distribution destination printer:
Next, processing in the printer PRT as the distribution destination printer will be described with reference to FIGS. FIG. 6 is a flowchart showing a processing routine of connection establishment processing. FIG. 7 is a first flowchart showing the processing routine of the printing process. FIG. 8 is a second flowchart showing the processing routine of the printing process. FIG. 9 is an explanatory diagram conceptually showing a state in which a plurality of printing processes are executed in parallel.

  First, connection establishment processing executed by the TCP / IP unit 10 of the printer PRT will be described. When the printer PRT is powered on, this connection establishment process is always executed. The TCP / IP unit 10 determines whether or not the number of currently held connections is less than 3 (step S202). If it is determined that three connections are already held (step S202: NO), the TCP / IP unit 10 waits until the number of held connections becomes less than three. That is, the TCP / IP unit 10 does not establish a new connection so that three or more connections are not simultaneously held. The maximum number of connections held (3 in this embodiment) is set to be equal to the number of print jobs (3 in this embodiment) that can be received and processed in parallel by the printer PRT.

  On the other hand, when the TCP / IP unit 10 determines that the number of currently established connections is less than 3 (step S202: YES), the TCP / IP unit 10 monitors the presence / absence of a connection establishment request (step S202). S204). Since a device that intends to transmit a print job (hereinafter also referred to as a transmitting device) needs to establish a connection prior to transmission of the print job, it first transmits a connection establishment request (SYN packet). . For example, the above-described custom network board 100 (distribution control unit 40) or client CL corresponds to the transmission device. When the TCP / IP unit 10 receives the connection establishment request (step S204: YES), the TCP / IP unit 10 establishes a connection for receiving a print job from the device that has transmitted the connection establishment request (step S206). Thereafter, the TCP / IP unit 10 returns to step S202.

  With reference to FIGS. 7 to 8, a description will be given of a printing process executed when a connection is established by the above-described connection establishment process. When the connection is established, a print job is transmitted from the transmission device via the connection. The sub-reception unit that is not receiving another print job among the first reception unit 51 to the third reception unit 53 waits for the print job to be transmitted (step S302), and the print job is transmitted. Then, the received print job is received (step S304). Hereinafter, the description will be continued assuming that the first receiving unit 51 receives a print job. Since the first receiving unit 51 needs to store the received print job in the memory 30, the amount of data that can be received at one time is limited. For this reason, the first receiving unit 51 sequentially receives print jobs from the head for a predetermined amount of data that can be received at one time.

  Subsequently, the first interpretation unit 91 interprets the received print job and generates image data (step S306). The generated image data is stored in the memory 70. Next, it is checked whether image data for one page has been generated (step S308). Whether or not one page of image data has been generated is determined by whether or not the print job has been interpreted until a page break request. If image data for one page has been generated (step S308: YES), the first interpretation unit 91 issues a print request for the generated image data for one page (step S310). If a print request for one page is issued, or if image data for one page has not been generated (step S308: NO), whether there is an unprocessed print job that has already been received Is examined (step S312). If there is an unprocessed print job (step S312: YES), the process returns to step S306 to interpret the unprocessed print job.

  On the other hand, if there is no unprocessed print job (step S312: NO), it is checked whether or not there is a connection termination request from the transmission device (step S314). When the sending device finishes sending all print jobs, it sends a connection termination request. Accordingly, if there is no connection termination request from the transmitting device (step S314: NO), a further print job is transmitted from the transmitting device, so the process returns to step S304 and the above steps (S304 to S312) are repeated.

  On the other hand, when there is a connection termination request from the transmitting device (step S314: YES), all the print jobs have been received, so the connection is terminated (step S316). Thereafter, it is checked whether or not there is image data for which no print request has been issued in the memory 70 (step S318). If there is no unissued image data (step S318: NO), this process is terminated. On the other hand, if there is unissued image data (step S318: YES), the first interpretation unit 91 issues a print request for one page for the unissued image data (step S320), and this process ends. Is done. Here, in step S318, the presence of unissued image data is checked because there is a page break request at the end of the print job and there is no page break request. If there is a page break request at the end of the print job, there is no unissued image data after the end of the connection (step S318: NO), and the process is terminated as it is. On the other hand, if there is no page break request at the end of the print job, unissued image data remains in the memory 70 after the end of the connection (step S318: YES), so the processing in step S320 described above is necessary.

  As described above, print requests for one page are sequentially issued while receiving a print job. Since the memory 70 for storing the image data has a limit, this process is temporarily suspended when the remaining capacity of the memory 70 is exhausted. When printing is executed in response to a print request for one page by the process shown in FIG. 8 to be described later, the printed image data is erased and this process is resumed.

  In parallel with the process shown in FIG. 7, a process for executing printing is performed in response to a print request as shown in FIG. In this process, a print request is issued (FIG. 7: steps S312 and S314) (step S402). When the issued print request is received (step S402: YES), the printer engine 80 changes to another print request. It is checked whether the print job is being printed (step S404). When the printer engine 80 is printing another print job (step S404: YES), the printer engine 80 waits until the printing order of the print job in this process comes because printing cannot be executed immediately (step S406). If the printer engine 80 is not printing (step S404: NO), the printer engine 80 is occupied for this processing (step S408), and the printer engine 80 converts the image data generated in the processing shown in FIG. Based on this, printing for one page is executed (step S410). For example, in the case of a print job that prints 10 copies of a printed matter including a part of 5 pages, if a print request for the first page is received, 10 copies of the first page are printed in this step.

  The printed paper (printing paper) is sent to the sorter 85, and the sorter 85 stores the print paper in a specific paper discharge bin among the plurality of paper discharge bins (step S412). A specific paper discharge bin is determined for each print job, and print paper for one print job is stored in one paper discharge bin. When the printing for one page is completed, the printer engine 80 is released from the occupation by this processing (step S414). That is, when there is another print process waiting until the printing order comes, the occupation of the printer engine 80 is transferred to the other print process.

  Subsequently, it is determined whether or not the printed page is the last page (step S416). If it is determined that the printed page is not the last page (step S416: NO), the process returns to step S402 to receive a print request for the next page. Wait for it. On the other hand, if it is determined that the printed page is the last page or the last page (step S416: YES), this process is terminated.

  The printer PRT can process up to three printing processes described above in parallel. In the above description, the print job reception (step S302) and the print job interpretation process (step S304) are executed by the first reception unit 51 and the first interpretation unit 91, respectively. When a plurality of printing processes are processed in parallel, these processes are the first receiving unit 51 and the first interpreting unit 91, the second receiving unit 52 and the second interpreting unit 92, or the third receiving unit. 53 and the third interpreter 93 are processed separately, so that they are processed without affecting each other. FIG. 9 shows that print jobs respectively transmitted from three transmission devices (client CLa, distribution control unit 40 of printer PRT4, and distribution control unit 40 of printer PRT1) are processed in parallel in the printer PRT. It is shown.

  However, since the printer PRT has one printer engine 80, it is necessary to exclusively use the printer engine 80 in a plurality of print processes processed in parallel. In this embodiment, as can be understood from the processing shown in FIG. 8 described above, each printing process releases the occupation of the printer engine 80 every time printing is performed one by one. In this way, each print process takes turns and sequentially occupies the printer engine 80, so that a plurality of print processes can proceed in parallel. In other words, the printer PRT can process a plurality of print jobs in parallel by printing a plurality of print jobs one by one.

  According to the printer PRT in the present embodiment described above, the number of connections for receiving print jobs simultaneously is limited to the number of print jobs (three) that can be received in parallel. As a result, if the connection between the transmission device and the printer PRT is established, the print job transmitted through the connection is always received by the printer PRT, so that the transmission device is not put into a so-called standby state.

  Therefore, if the printer PRT in the embodiment is used as a distribution destination printer in the distributed printing process, it is possible to prevent the occurrence of deadlock in the distributed printing process. Here, deadlock means a problem that the distributed printing process is completely stopped. For example, there is a distributed printing system including two or more custom network boards 100 (distribution control unit 40) and two or more distribution destination printers each of which can be designated as a distribution destination of a print job. And In this system, when two or more custom network boards 100 try to send print jobs to two or more distribution destination printers almost simultaneously by distributed printing processing, a deadlock may occur conventionally. .

  Here, for ease of understanding, a mechanism for causing a deadlock will be described with reference to FIGS. FIG. 10 is an explanatory diagram conceptually showing reception of a print job in a conventional printer. FIG. 11 is an explanatory diagram showing a communication sequence when a deadlock occurs. FIG. 12 is an explanatory diagram conceptually showing a case where a deadlock occurs.

  First, reception of a print job by a conventional printer will be described with reference to FIG. In the conventional printer, the number of connections that can be simultaneously held is larger than the number of print jobs that can be received in parallel. For example, in the conventional printer PR shown in FIG. 10, the number of connections that can be simultaneously held is eight, and the number of print jobs that can be received in parallel is one.

  FIG. 10 conceptually shows a state in which the three clients CLa to CLc attempt to send print jobs in parallel to such a printer PR. Symbols CN1 to CN3, the connections established between the TCP / IP units 13 of the clients CLa to CLc and the TCP / IP unit 1 of the printer PR, the numbers at the end of the symbols indicate the connection established Shows the time sequence. That is, the TCP / IP unit 13 of the client CLa is first, the TCP / IP unit 13 of the client CLc is second, the TCP / IP unit 13 of the client CLb is third, and the TCP / IP unit of the printer PR. 1 indicates that a connection has been established.

  As described above, the TCP / IP unit 1 can hold a plurality of connections, whereas the receiving unit 2 of the printer PR is configured to receive a print job one by one. This is because the printer main body (not shown) of the printer PR cannot process a plurality of print jobs in parallel. The receiving unit 2 preferentially receives a print job transmitted via a previously established connection. In the specific example shown in FIG. 10, the receiving unit 2 first receives a print job transmitted from the client CLa via the connection CN1 established first (FIG. 10A). The receiving unit 2 supplies the received print job to the printer body according to the printing protocol. While the receiving unit 2 receives the print job transmitted from the client CLa, the other clients CLb and CLc are kept waiting while holding the connections CN3 and CN2. In more detail, in communication using the TCP protocol, data flow control (control to permit or prohibit data flow) is performed, which is a higher-level application of the TCP / IP unit 1 via a connection. When the receiving unit 2 does not receive a print job (not received from the TCP / IP unit 1), the TCP / IP unit 1 prohibits data flow by flow control. That is, it notifies the transmission source TCP / IP unit (in this example, the client CLb, the TCP / IP unit 13 of CLc) not to transmit data. In this state, the clients CLb and CLc cannot transmit data and wait until data transmission is permitted. Hereinafter, such a state is referred to as a standby state.

  When the receiving unit 2 receives all the print jobs transmitted from the client CLa, the TCP / IP unit 1 ends the connection CN1. After the connection CN1 is terminated, as illustrated in FIG. 10B, the reception unit 2 receives a print job from the client CLc via the connection CN2 that is established second. When the receiving unit 2 receives a print job transmitted via the connection CN2 (receives from the TCP / IP unit 1), the TCP / IP unit 1 permits the data flow by the flow control described above. That is, the TCP / IP unit 1 permits the transmission of data to the TCP / IP unit 13 of the transmission source (client CLc). Thus, the client CLc is released from the standby state and can send a print job.

  As described above, the receiving unit 2 sequentially receives the print jobs in the order in which the connections are established, and sequentially supplies the received print jobs to the printer main body, whereby the printing is sequentially executed in the order of access by the clients.

  Using the above-described conventional printers PR (referred to as printer PR2 and printer PR3) as distribution destination printers, for example, the distribution control unit 40 of the printer PRT1 and the distribution control unit 40 of the printer PRT4 are almost simultaneously respectively. Consider a case where distributed printing processing is executed. Assume that the distribution control unit 40 of the printer PRT1 and the distribution control unit 40 of the printer PRT4 each establish a connection to transmit print jobs to the two printers PR2 and PR3. As described above, since the TCP / IP units 1 of the printers PR2 and PR3 can simultaneously hold a plurality of connections, the establishment of each connection is successful. In FIG. 11, white circles indicate the timing at which connections between the distribution control unit 40 of the printer PRT1 and the receiving units 2 of the printer PR2 and the printer PR3 are established. On the other hand, the black circles indicate the timing at which the connection between the distribution control unit 40 of the printer PRT4 and the receiving units 2 of the printer PR2 and the printer PR3 is established.

  As shown in FIG. 11, the connection with the receiving unit 2 of the printer PR2 is established first by the distribution control unit 40 of the printer PRT1. Accordingly, the receiving unit 2 of the printer PR2 receives the print job transmitted from the distribution control unit 40 of the printer PRT1 preferentially, and the distribution control unit 40 of the printer PRT4 does not receive the print job until the reception is completed. It will be in a waiting state.

  On the other hand, as shown in FIG. 11, the connection with the receiving unit 2 of the printer PR3 is established first by the distribution control unit 40 of the printer PRT4. Accordingly, the receiving unit 2 of the printer PR3 preferentially receives the print job transmitted from the distribution control unit 40 of the printer PRT4, and the distribution control unit 40 of the printer PRT1 does not receive the print job until the reception is completed. It will be in a waiting state. In FIG. 11, thick solid lines indicate connections CN12 and CN43 that receive print jobs preferentially, and thin solid lines indicate connections C42 and C13 that are in a standby state.

  From such a state, the distribution control unit 40 of the printer PRT1 executes the above-described packet distribution PD (FIG. 5) via the established connections C12 and C13, and prints on each receiving unit 2 of the printers PR2 and PR3. Try to submit a job. In such a case, the packet P1 transmitted to the receiving unit 2 of the printer PR2 is received immediately because the priority of the connection CN12 is high, but the packet P1 transmitted to the receiving unit 2 of the printer PR3 is received by the connection CN13. Not received due to low priority. For this reason, the distribution control unit 40 of the printer PRT1 cannot complete the first packet distribution PD and enters a standby state.

  Similarly, the distribution control unit 40 of the printer PRT4 tries to transmit a print job to the receiving units 2 of the printers PR2 and PR3 via the established connections C42 and C43. In such a case, the packet P1 transmitted to the receiving unit 2 of the printer PR3 is received immediately because the priority of the connection CN43 is high, but the packet P1 transmitted to the receiving unit 2 of the printer PR2 is received by the connection CN42. Not received due to low priority. Therefore, similarly to the distribution control unit 40 of the printer PRT1, the distribution control unit 40 of the printer PRT4 cannot complete the first packet distribution PD and enters a standby state.

  As a result, both of the distributed printing processes by the distribution control unit 40 of the printer PRT1 and the distribution control unit 40 of the printer PRT4 are completely stopped. The standby state of the distribution control unit 40 of the printer PRT1 is not canceled until the distributed printing process by the distribution control unit 40 of the printer PRT4 is completed, while the standby state of the distribution control unit 40 of the printer PRT4 is the distribution control of the printer PRT1. This is because the problem cannot be resolved until the distributed printing process by the unit 40 is completed.

  The deadlock as shown in FIG. 11 occurs in the case as shown in FIG. To explain conceptually, there are a plurality of distribution control units on the transmission side of the print job and a plurality of reception units on the reception side, and the connection between the distribution control unit and the reception unit depends on the connection for communication. Deadlocks can occur in systems where closed rings can be formed that alternately connect to the receiver. As described above, a ring of connections is established, and when the distributed printing process is executed in a state where all the receiving units on the ring have at least one connection that is in a standby state, a deadlock state occurs. In FIG. 12, the numbers assigned to the connections are 1 for a connection in an immediate reception state and 2 for a connection in a standby state.

  If the distributed printing process as described above is executed by using the printer PRT according to the present embodiment as the distribution destination printer, the distribution control unit 40 to transmit the print job is not put into a standby state. Can be prevented. For example, even if the connection is established at the timing shown in FIG. 11, the print job transmitted from the distribution control unit 40 of the printer PRT1 and the print job transmitted from the distribution control unit 40 of the printer PRT4 are executed in parallel. This is because the printing process can be executed in parallel. Further, the number of connections exceeding the number that can be received in parallel (three in this embodiment) is never established (FIG. 6).

  Furthermore, the print job interpretation unit 90 of the printer PRT in this embodiment includes a plurality of sub-interpretations units (first interpretation unit 91 to third interpretation unit 93), and can interpret the print job in parallel. As a result, it is possible to proceed with the printing process by quickly interpreting a plurality of print jobs received in parallel.

  In addition, since a plurality of print jobs are processed by repeating printing one page at a time for each print job, the printer PRT does not need to receive all the print jobs at once. As a result, the capacity of the memory 30 and the memory 70 mounted on the printer PRT can be reduced.

  Further, even when a plurality of print jobs (up to three) are processed in parallel, the print paper is stored separately for each print job by the sorter 85 including three storage units. As a result, the inconvenience that print papers of a plurality of print jobs are mixed is solved.

B. Variation:
The number m of print jobs that can be received in parallel by the printer PRT is not limited to 3 shown in the above embodiment. In this embodiment, the number is set in accordance with the number 3 of the accommodating portions (sheet discharge bins) of the sorter 85. However, when a sorter having a larger number of accommodating portions is used, the value of m depends on the number of accommodating portions. May also be increased. The number m of print jobs that can be received by the printer PRT does not always have to be a constant value for each printer PRT, and may be dynamically changed according to the state of the printer PRT. For example, the value of m can be set in accordance with the number of paper discharge bins that are in a state that can accommodate printing paper among the paper discharge bins of the sorter 85. Specifically, a sensor for detecting whether or not the printing paper is stored in the paper discharge bin is provided for each paper discharge bin of the sorter 85, and the number of paper discharge bins that do not contain the print paper is set to a value of m. It is also good. In any case, with respect to the value of m set at that time, the number n of connections that can be simultaneously held is limited to a natural number of m or less. By doing so, the above-described actions and effects can be obtained.

  In the above embodiment, one printer engine 80 is provided for each printer PRT, but a plurality of printer engines 80 may be provided for each printer PRT. For example, in the above embodiment, when one printer PRT has three printer engines 80, one printer engine 80 is assigned to each of the three sub-interpretation units (first interpretation unit 91 to third interpretation unit 93). Therefore, the printing process can be executed at a higher speed.

  In the above embodiment, when a plurality of print jobs are processed in parallel, printing one page at a time for each print job is repeated, but the repeating unit is not limited to one page. For example, two pages or three pages may be repeated. This can be changed as appropriate according to the capacity of the memory 70 for temporarily storing image data.

  Various types of printer engine 80 in the above embodiment can be used. For example, not only a laser type but also any type of printer engine such as an ink jet type, a sublimation type, a dot impact type, and a thermal transfer type can be used.

  As mentioned above, although the Example and modification of this invention were demonstrated, this invention is not limited to these Example and modification at all, and implementation in a various aspect is possible within the range which does not deviate from the summary. It is.

1 is an explanatory diagram illustrating a schematic configuration of a distributed printing system in an embodiment. FIG. The block diagram which shows the internal structure of each apparatus which comprises a distributed printing system. The conceptual diagram which shows the data structure of a print job. 9 is a flowchart showing a processing routine for distributed printing processing. FIG. 3 is an explanatory diagram illustrating an example of a communication sequence in which a print job is transmitted to a plurality of print job reception units. The flowchart which shows the process routine of a connection establishment process. The 1st flowchart which shows the process routine of a printing process. FIG. 9 is a second flowchart showing a processing routine for printing processing. FIG. Explanatory drawing which shows notionally a mode that several printing processing is performed in parallel. Explanatory drawing which shows notionally reception of the print job in the conventional printer. Explanatory drawing which shows the communication sequence in case a deadlock occurs. Explanatory drawing which shows notionally the case where a deadlock occurs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... TCP / IP part 11 ... Application 12 ... Print job transmission part 13 ... TCP / IP part 20 ... CPU
DESCRIPTION OF SYMBOLS 30 ... Memory 40 ... Distributed control part 50 ... Print job receiving part 51 ... 1st receiving part 51 ... 1st receiving part 52 ... 2nd receiving part 53 ... 3rd Receiver 60 ... CPU
DESCRIPTION OF SYMBOLS 70 ... Memory 80 ... Printer engine 85 ... Sorter 90 ... Print job interpretation part 91 ... 1st interpretation part 92 ... 2nd interpretation part 93 ... 3rd interpretation part 100. .. Custom network board 200 ... Network board 400 ... Header 450 ... Data part 500 ... Print job data 501 ... Job control language part 502 ... Page description language part PRT, PR ... Printer CLa to CLc ... Client

Claims (11)

A printing device,
A communication unit that performs communication using a connection-type protocol, the communication unit holding a connection for the communication;
A print job receiving unit that receives a print job via the connection, wherein the number of print jobs that can be received in parallel is m (m is a natural number);
A print execution unit that executes print processing in parallel for the received print job;
With
The number of connections simultaneously held by the communication unit is a printing apparatus set to m or less.   The print job is divided into a plurality of packets, and packet distribution in which each of the packets is transmitted to two or more distribution destination printing apparatuses is repeatedly executed for each of the divided packets. The printing apparatus according to claim 1, wherein the printing apparatus is connected to a print control apparatus capable of transmitting to each of the distribution destination printing apparatuses and used as the distribution destination printing apparatus. The printing apparatus according to claim 1 or 2,
The print execution unit
A print job interpretation unit that interprets the received print job and issues a print request, the print job interpretation unit capable of executing the interpretation process in parallel for the m print jobs; ,
A printing unit that outputs a print result of the print job based on the issued print request;
A printing apparatus. The printing apparatus according to claim 3.
The printing unit is configured to output a plurality of print job print results by repeatedly outputting a predetermined number of print results of each print job. The printing apparatus according to claim 4, further comprising:
A printing apparatus comprising a sorter mechanism that stores a print result output by the printing unit in a plurality of storage units for each print job. The printing apparatus according to claim 5, wherein
The number m of print jobs that can be received in parallel is the number of storage units included in the sorter mechanism. The printing apparatus according to any one of claims 1 to 6,
The number m of the print jobs that can be received in parallel varies according to the state of the printing apparatus. The printing apparatus according to claim 5, wherein
The number m of print jobs that can be received in parallel is the number of storage units that are capable of storing a print result among the storage units of the sorter mechanism. The printing apparatus according to claim 3.
The printing apparatus includes m printing units. Printing method,
A first step of simultaneously holding up to n connections (n is a natural number) for communication using a connection-type protocol in response to a request;
A second step of receiving in parallel each print job transmitted via the held connection;
A third step of executing print processing in parallel for the print jobs received in parallel;
With
The printing method in which n is equal to or less than the number m (m is a natural number) of print jobs that can be received in parallel in the second step. A computer program for controlling a printing apparatus,
A communication unit that performs communication using a connection-type protocol, the first function holding a connection for the communication;
A second function for receiving a print job via the connection, wherein the number of print jobs that can be received in parallel is m (m is a natural number);
A third function for executing print processing in parallel for the received print job;
A fourth function for setting the number of connections simultaneously held by the communication unit to m or less;
Computer program that makes a computer realize

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