Abstract:
A system and a method are provided for printing on a network. In one embodiment, broadly stated the method comprises the steps of: generating a print job ticket in a client, the print job ticket being associated with a full print job; transmitting the print job ticket to a queue server; placing the print job ticket in a queue in the queue server; transmitting the print job ticket from the queue server to a print server; transmitting a request for a full print job from the print server to the client; and, transmitting the full print job that encompasses a document to be printed from the client to the print server in response to the request.

Description:
TECHNICAL FIELD 
     The present invention is generally related to the field of network printing and, more particularly, is related to a system and method for network printing using a peer hybrid printing protocol. 
     BACKGROUND OF THE INVENTION 
     In printing documents from client computers and other devices to network printers, various printing protocols are used. Three such typical printing protocols employed include client-server printing, server-side-rendering (SSR) client-server printing, and peer-to-peer printing. These protocols are used by the various devices on the network to cause the printing of a particular document from the client. Such devices may include, for example, one or more clients, a queue server, a print server, and a printer, etc. 
     To print a document using client-server printing, for example, an application in a client first makes graphical device interface (GDI) calls to the operating system in the client. The operating system then creates enhanced meta file data (EMF data) from the GDI calls that are handed to a printer driver. The printer driver then renders the EMF data into printer ready bits (PRB) that form a print job. The print job is applied to the operating system to be transmitted over the network to the queue server for printing. 
     The queue server then receives the print job and places it in a queue associated with a particular printer. When the printer is ready to receive the print job, the queue server transmits the print job over the network to the print server. The print server then applies the print job to the printer for printing. Unfortunately, the client-server approach requires the entire document to be transmitted on the network twice, thereby consuming a potentially large amount of network bandwidth. 
     In server-side-rendering, (SSR) client-server printing, an application in a client first makes GDI calls to the operating system in the client. The operating system then creates EMF data from the GDI calls. The EMF data is transmitted over the network to a queue server. In the queue server, the EMF data is placed in a queue for printing. When the document is to be printed, the corresponding EMF data is applied to a printer driver in the queue server that renders the EMF data into printer ready bits (PRB) that form a print job. When the printer is ready to receive the print job, the print job is applied to the operating system in the queue server to be transmitted over the network to the print server for printing. The print server then applies the print job to the printer for printing. Unfortunately, the SSR client-server approach also requires the entire document to be transmitted on the network twice, once as EMF data and once as printer ready bits. This results in the consumption of a potentially large amount of network bandwidth. In addition, the centralization of the printer driver on the queue server can stress the computing capacity of the queue server to effectively render the EMF data into printer ready bits (PRB). This is especially a concern given that a number of printer drivers may be placed on the queue server to service a number of printers. 
     In peer-to-peer printing, an application in a client first makes GDI calls to the operating system in the client. The operating system then creates EMF data from the GDI calls that are handed to a printer driver in the client. The printer driver then renders the EMF data into printer ready bits (PRB) that form a print job. The print job is applied to the operating system in the client to be transmitted over the network directly to the print server for printing. 
     When the print server is ready to receive data, the operating system in the client transmits the print job to the print server. The print server then applies the print job to the printer for printing. Although, the peer-to-peer printing approach only requires the entire document to be transmitted on the network once, the peer-to-peer approach does not facilitate centralized printer control or queuing. 
     SUMMARY OF THE INVENTION 
     In light of the foregoing, the present invention provides for a system and method for network printing of a document. In one embodiment, the network includes a client coupled to the network, the client having a first processor coupled to first local interface and a first memory coupled to the first local interface. The client also includes send job logic stored on the first memory and executable by the first processor. The send job logic includes logic to generate a print job ticket associated with a full print job, and logic to transmit the print job ticket to a queue server that is coupled to the network. 
     The queue server includes a second processor coupled to second local interface and a second memory coupled to the second local interface. The queue server also includes print queue logic stored on the second memory and executable by the second processor. The print queue logic includes logic to place the print job ticket in a queue in the queue server, and logic to transmit the print job ticket from the queue server to a print server that is coupled to the network. 
     The print server has a third processor coupled to third local interface and a third memory coupled to the third local interface. The print server further includes print server logic stored on the third memory and executable by the third processor. The print server logic comprises logic to determine an address of the client on the network from the print job ticket received from the queue server, logic to transmit a request for a full print job to the client, and logic to apply the full print job received from the client to the printer. 
     In addition to the above system, further aspects of the present invention include the functionality of each of the client, queue server, and print server related to the printing protocol employed to print a document on a network printer. 
     The present invention may also be viewed as a method for printing on a network. Broadly stated, the method comprises the steps of: generating a print job ticket in a client, the print job ticket being associated with a full print job; transmitting the print job ticket to a queue server; placing the print job ticket in a queue in the queue server; transmitting the print job ticket from the queue server to a print server; transmitting a request for a full print job from the print server to the client; and, transmitting the full print job from the client to the print server in response to the request. 
     In addition to the above method, further aspects of the present invention include the steps taken with reference to the individual client, queue server, and print server related to the printing protocol employed to print a document on a network printer. 
     The systems and method of the present invention provide several advantages, such as, printing documents on a network printer while using less bandwidth and at the same time retaining centralized control over the printing functions of the network. 
     Other features and advantages of the present invention will become apparent to a person with ordinary skill in the art in view of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The invention can be understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Also, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
     FIG. 1 is a block diagram of a network according to an embodiment of the present invention; 
     FIG. 2 is a block diagram that depicts a printing protocol implemented on the network of FIG. 1; 
     FIG. 3 is a flow chart of job send logic executed by a client in the network of FIG. 1 to implement the printing protocol of FIG. 2; 
     FIG. 4 is a flow chart of print queue logic executed by a queue server in the network of FIG. 1 to implement the printing protocol of FIG. 2; and 
     FIG. 5 is a flow chart of print server logic executed by a print server in the network of FIG. 1 to implement the printing protocol of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIG. 1, shown is a printing network  100  according to an embodiment of the present invention. The printing network  100  includes a network  103  to which is coupled a client  106 , a queue server  109 , and a print server  113 . A printer  116  is coupled to the print server  113  as shown. 
     The client  106  includes a processor circuit that includes a processor  133  and a memory  136 , both of which are coupled to a local interface  139 . The local interface  139  may be a data bus with an accompanying control bus as known by those with ordinary skill in the art. The client  106  further includes a network interface  143  that couples the local interface  139  to the network  103 . Through the network interface  143 , data may be transmitted from the local interface  139  to the network  103  to any other device on the printing network  100 . Also, the network interface  143  makes data transmitted via the network  103  available on the local interface  139 . Thus, the network interface  143  may be, for example, a network interface card, modem, or other interface that includes appropriate buffer circuitry and transmission circuitry, etc., to accomplish these tasks. In this respect, the network  103  may comprise a local area network, a wide area network, or the Internet, etc. 
     The client  106  also features an operating system  153  and a printer driver  156  stored in the memory  136  and executable by the processor  133 . The operating system  153  is executed to control and/or perform the various functions of the client  106  in a similar manner to operating systems known by those with ordinary skill in the art. However, according to the present invention, the operating system  153  further includes job send logic  159  that is executed in order to interface with the queue server  109  and the print server  113  to print a document as will be discussed. Such a document (not shown) generally results from the operation of a particular application (not shown) on the client  106  as is generally known by those with ordinary skill in the art. The printer driver  156  is employed by the client device  106  to render enhanced meta file (EMF) data into printer ready bits (PRBs) as is known by those with ordinary skill in the art. The particular printer driver  156  that is used is compatible with the printer  116 . 
     The queue server  109  includes a processor circuit that includes a processor  173  and a memory  176 , both of which are coupled to a local interface  179 . The local interface  179  may be a data bus with an accompanying control bus as known by those with ordinary skill in the art. The queue server  109  further includes a network interface  183  that couples the local interface  179  to the network  103 . The network interface  183  is similar to the network interface  143  and is not described in great detail. 
     The queue server  109  further comprises an operating system  193  that is executed to control and/or perform the various functions of the queue server  109  in a similar manner to operating systems known by those with ordinary skill in the art. However, according to the present invention, the operating system  193  additionally includes print queue logic  196  that is executed to interface with the client  106  and the print server  113  in accomplishing the tasks of queuing and generally printing a document from the client  106  on the printer  116  as will be discussed. 
     The print server  113  includes a processor circuit that features a processor  213  and a memory  216 , both of which are coupled to a local interface  219 . The local interface  219  may be a data bus with an accompanying control bus as known by those with ordinary skill in the art. The print server  113  further includes a network interface  223  that couples the local interface  219  to the network  103 . The network interface  223  is similar to the network interface  143  and is not described in great detail. 
     The print server  113  also includes a printer interface  226  that may be a printer interface card that couples the printer  116  to the local interface  219 . In this regard, the printer interface  226  may comprise an appropriate printer card, etc., as known by those with ordinary skill in the art. 
     The print server  113  further comprises an operating system  233  that is executed to control and/or perform the various functions of the print server  113  in a similar manner to operating systems known by those skilled in the art. However, according to the present invention, the operating system  233  additionally includes print server logic  236 . The print server logic  236  is executed to interface with the client  106  and the queue server  109  in accomplishing the tasks of queuing and generally printing a document from the client  106  on the printer  116  as will be discussed. 
     Additionally, the memories  136 ,  176 , and  216  may include both volatile and nonvolatile memory components. Volatile components are those that do not retain data values upon loss of power. Conversely, nonvolatile components retain data upon a loss of power. Thus, the memories  136 ,  176 , and  216  may comprise, for example, random access memory (RAM), read-only memory (ROM), hard disk drives, floppy disks accessed via an associated floppy disk drive, compact disks accessed via a compact disk drive, magnetic tapes accessed via an appropriate tape drive, and/or other memory components, or a combination of any two or more of these memory components. 
     Also, each of the processors  133 ,  173 ,  213  may represent multiple processors operating in parallel and each of the memories  136 ,  176 ,  216  may represent multiple memories. In such a case, each of the local interfaces  139 ,  179 ,  219  may be an appropriate network that facilitates communication between any two of the multiple processors or between any one processor and any one of the memories, etc. In addition, the processors  133 ,  173 ,  213 , memories  136 ,  176 , and  216 , and local interfaces  139 ,  179 ,  219  may be electrical or optical in nature. The memories  136 ,  176 , and  216  may also be magnetic in nature. 
     The client  106 , the queue server  109 , and the print server  113  may include appropriate input/output devices (not shown). In this regard, the input devices may include, for example, but are not limited to a keyboard, keypad, touch pad, touch screen, microphone, mouse, joystick, or one or more push buttons, etc. User output devices may include display devices, indicator lights, speakers, printers, etc. Such display devices may be, for example, cathode ray tubes (CRTs), liquid crystal display screens, gas plasma-based flat panel displays, indicator lights, light emitting diodes, and other display devices. 
     In addition, the queue server  109  and the print server  113  may also be combined into a single server that performs the functions of both, taking the operation requirements of both into account. That is to say, a combined queue and print server should have a fast enough operating speed to accomplish both functions simultaneously. 
     With to reference to FIG. 2, shown is a block diagram of the printing network  100  that depicts a printing protocol  300  according to an embodiment of the present invention. The printing protocol  300  provides for communication between the various devices of the printing network  100 . In particular, the printing protocol  300  includes a print job ticket  303 , a printer polling message  304 , a printer response message  306 , a request for full print job  309 , a full print job  313 , and a printer idle signal  316 . Each of these data communications are employed as part of the printing protocol  300  to cause a document that resides in the client  106  to be printed on the printer  116 . 
     Assuming that the client  106  includes an application that has generated a document to be printed on the printer  116 , the client  106  makes appropriate graphical device interface (GDI) calls to the operating system  153  (FIG.  1 ). The operating system  153  makes corresponding enhanced meta file (EMF) data from the GDI calls, and hands the EMF data to the printer driver  156 . The printer driver  156  renders the EMF data into printer ready bits (PRBs) and sends the resulting full print job to the operating system  153  in PRB format. The operating system  153  then spools the full print job to the memory  136 . 
     The client  106  then generates a print job ticket  303  that includes the address of the client  106  on the network  103 , the name or identification of the full print job, and any other pertinent information such as the number of pages to be printed, etc. The client  106  then transmits the print job ticket  303  to the queue server  109 . The queue server  109  places the print job ticket  303  in a printing queue maintained in the queue server  109 . The queue server  109  then transmits a printer polling message  304  to the print server  113  to determine if the printer  116  is available to print a document. The print server  113  responds with the printer response message  306  that informs the queue server  109  that the printer  116  is busy printing or is available. If the printer  116  is occupied with another print job, the queue server  109  waits for a period of time and then retransmits the printer polling message  304 . If the printer  116  is available, the queue server  109  then transmits the print job ticket  303  to the print server  113 . 
     Alternatively, rather than polling the print server  113  as to the printer availability, the queue server  109  may simply wait for a “printer available signal” from the print server  113  signifying that a previous print job sent to the printer  116  has finished. When the “printer available signal” is received, the queue server  109  is informed that the printer  116  is available for another print job. 
     Once the print server  113  receives the print job ticket  303 , the print server  113  examines it to ascertain the client  106  that originated the print job ticket  303 , assuming that there are a number of clients  106  on the network  103 . The print server  113  then transmits a “request for full print job”  309  to the client  106  based upon the client network address. 
     In response, the client  106  transmits the full print job  313  to the print server  113 . The full print job  313  includes the digital data that makes up the document to be printed in PRB format. Thereafter, the print server  113  transmits the full print job  313  to the printer  116  that prints the document, accordingly. Once the printer  116  has finished printing the document, the printer  116  transmits the printer idle signal  316  back to the print server  113 . The print server  113  then waits for another printer polling message  304  to begin the process again. Alternatively, if printer polling is not used by the queue server  109 , the print server  113  transmits a “printer available signal” to the queue server  109  to inform the queue server  109  that the printer is ready for the next print job. The print server  113  maintains the availability status of the printer  116  based upon the fact that it sent a full print job  313  to the printer  116  and/or received the printer idle signal  316  from the printer  116 . 
     With the foregoing in mind, reference is made to FIG. 3 that shows a flowchart of the job send logic  159  that is executed by the client  106  (FIG.  1 ). The job send logic  159  is executed by the processor  133  (FIG. 1) in order to fulfill the role or the client  106  in printing a document on the printer  116  (FIG. 1) according to the printing protocol  300  (FIG.  2 ). Beginning with block  350 , the job send logic  159  determines whether a document is to be printed as mandated by the operating system  153  (FIG.  1 ). If such is the case then the job send logic  169  moves to block  353  in which the print job ticket  303  (FIG. 2) is generated and transmitted to the queue server  109  (FIG.  2 ). If there is no document to be printed in block  350 , then the job send logic  159  moves to block  356  in which it is determined whether a request for full print job  309  (FIG. 2) has been received from the print server  113  (FIG.  2 ). Also, after the print job ticket  303  is transmitted to the queue server  109  in block  353 , the job send logic  159  moves to block  356  as shown. Thus, the job send logic  159  will continually move between blocks  350  and  356  waiting for either a document to be printed or a printer request to be received from the print server  113 . 
     If there is no request for full print job  309  received from the print server  113  in block  356 , then the job send logic  159  reverts back to block  350  as shown. On the other hand, if a request for full print job  309  is received by the client  106  in block  356 , then the job send logic  159  moves to block  359 . In block  359  the request for full print job  309  is matched with the corresponding print job that is stored in the local spool system of the client  106 . Thereafter, in block  363  the full print job  313  (FIG. 2) is transmitted to the print server  113  and in block  366  the full print job  313  is deleted in the client  106 . Thereafter, the job send logic  159  reverts back to block  350 . 
     With reference to FIG. 4, shown is a flowchart of the print queue logic  196  according to another embodiment of the present invention. The print queue logic  196  is executed by the processor  173  (FIG. 1) of the queue server  109  (FIG. 1) to perform the functions of the queue server  109  that relate to the printing protocol  300  (FIG.  2 ). Beginning with block  400 , the queue server  109  determines whether it has received a print job ticket  303  (FIG. 2) from the client  106  (FIG.  2 ). If so, then the print queue logic  196  moves to block  403 . If not, then the print queue logic  196  moves to block  406 . Assuming that the print queue logic  196  has moved to block  403 , the print job ticket  303  that is received from the client  106  is placed within a printing queue maintained in the queue server  109 . The printing queue may be stored, for example, in the memory  176  (FIG.  1 ). The print queue logic  196  then moves to block  406 . Upon reaching block  406 , the print queue logic  196  determines whether the printer  116  (FIG. 1) is either idle or printing a document. This is determined, for example, by transmitting the printer polling message  304  (FIG. 2) to the print server  113  to receive the printer response message  306 . The printer response message  306  indicates whether the printer  116  is available. Alternatively, the print queue logic  196  may simply wait to receive a printer available signal from the print server  113 . If the printer  116  is idle and ready to print a document in block  406 , then the print queue logic  196  moves to block  409 . Otherwise, the print queue logic  196  reverts back to block  400 . 
     In block  409  the print queue logic  196  determines whether there is a job in the queue that is to be printed. If so, then the print queue logic  196  proceeds to block  413 . Otherwise, the print queue logic  196  reverts back to block  400 . In block  413 , the print queue logic  196  transmits the print job ticket  303  (FIG. 2) to the print server  113 . Then, in block  416  the print job ticket  303  is deleted from the printing queue maintained within the queue server  109  as the job has been sent to the print server  113  for printing. Thereafter, the print queue logic  196  reverts back to block  400 . 
     With reference to FIG. 5, shown is a flowchart of the print server logic  236  that is executed by the processor  213  (FIG. 1) in the print server  113  (FIG.  1 ). The print server logic  236  is executed to perform the functions of the print server  113  that relate to the printing protocol  300  (FIG.  2 ). Beginning with block  450 , the print server logic  236  determines if a printer polling message  304  (FIG. 2) has been received. If so, then the print server logic  236  moves to block  453 . Otherwise, the print server logic  236  proceeds to block  456 . In block  453  the print server logic  236  determines the print status of the print server  113  and the printer  116 . When a print job is not being processed based on a previously received print job ticket  303 , then the print status is available. Otherwise, the print status is unavailable. The actual print status may be determined in block  453 , for example, by examining a bit in the memory  216  (FIG. 1) that maintains the print status. Specifically, the bit may be placed in a logical “0” state indicating an available status or in a logical “1” state indicating an unavailable status. Based on the print status, the print server logic  236  sends an appropriate printer response message  306  (FIG. 2) to the queue server that originally sent the printer polling message  304 . Thereafter, the print server logic  236  proceeds to block  456 . 
     In block  456 , the print server logic  236  determines whether a print job ticket  303  has been received from the queue server  109 . If so, then the print server logic  236  moves to block  459 . If not, then the print server logic  236  proceeds to block  463 . In block  459  the print server logic  236  sets the print status to “unavailable”. This may be accomplished, for example, by setting the previously mentioned printer status bit to a logical “1”. Thereafter, in block  466  the network address of the client  106  (FIG. 1) from which the print job ticket  303  originated is determined. Next, in block  469  the print server logic  236  transmits a request for full print job  309  to the client  106 . The print server logic  236  then proceeds to block  463 . 
     In block  463  the print server logic  236  determines whether data from a full print job  313  (FIG. 2) is available from the client  106 . If so, then the print server logic  236  responds by moving to block  473 . If not, the print server logic  236  reverts back to block  450  as shown. In block  473 , the data from the full print job  313  is applied to the printer  116  for printing and the print server logic  236  then moves on to block  476  as shown. 
     In block  476  the print server logic  236  determines whether the full print job  313  has finished printing on the printer  116 . If so, then the print server logic  236  proceeds to block  479 . If not, then the print server logic  236  reverts back to block  450  as shown. In block  479  the print server logic  236  sets the print status to “available” by setting the status bit previously mentioned, for example, to a logic “0”. Thereafter, the print server logic  236  reverts back to block  450 . 
     Although the logic  159  (FIG.  1 ),  196  (FIG.  1 ), and  236  (FIG. 1) of the present invention is embodied in software as discussed above, as an alternative the logic  159 ,  196 , and  236  may also be embodied in hardware or a combination of software and hardware. If embodied in hardware, the logic  159 ,  196 , and  236  can be implemented as a circuit or state machine that employs any one of or a combination of a number of technologies. These technologies may include, but are not limited to, discrete logic circuits having logic gates for implementing various logic functions upon an application of one or more data signals, application specific integrated circuits having appropriate logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), or other components, etc. Such technologies are generally well known by those skilled in the art and, consequently, are not described in detail herein. 
     The flow charts of FIGS. 3-5 show the architecture, functionality, and operation of an implementation of the logic  159 ,  196 , and  236 . If embodied in software, each block may represent a module, segment, or portion of code that comprises one or more executable instructions to implement the specified logical function(s). If embodied in hardware, each block may represent a circuit or a number of interconnected circuits to implement the specified logical function(s). Although the flow charts of FIGS. 3-5 show a specific order of execution, it is understood that the order of execution may differ from that which is depicted. For example, the order of execution of two or more blocks may be scrambled relative to the order shown. Also, two or more blocks shown in succession in FIGS. 3-5 may be executed concurrently or with partial concurrence. It is understood that all such variations are within the scope of the present invention. 
     Also, the logic  159 ,  196 , and  236  can be embodied in any computer-readable medium for use by or in connection with an instruction execution system such as a computer/processor based system or other system that can fetch or obtain the logic from the computer-readable medium and execute the instructions contained therein. In the context of this document, a “computer-readable medium” can be any medium that can contain, store, or maintain the logic  159 ,  196 , and  236  for use by or in connection with the instruction execution system. The computer readable medium can comprise any one of many physical media such as, for example, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor media. More specific examples of a suitable computer-readable medium would include, but are not limited to, a portable magnetic computer diskette such as floppy diskettes or hard drives, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory, or a portable compact disc. 
     Many variations and modifications may be made to the above-described embodiment(s) of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention.