Abstract:
An apparatus for assigning a print job is provided. The apparatus includes a detector configured to detect an ambient temperature of each of a plurality of areas, each of the areas including at least one printer and at least one air conditioning system; a selection portion configured to select a printer included in a suitable area of the areas, the suitable area being an area where the ambient temperature detected is lower than a predetermined temperature; and an issuing portion configured to give the print job to the printer selected.

Description:
This application is based on Japanese patent application No. 2011-198336 filed on Sep. 12, 2011, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a technology for assigning a job to any one of apparatuses. 
     2. Description of the Related Art 
     In recent years, many different techniques for energy saving have been proposed. An example of methods for energy saving is to reduce power required to control the temperature of a room in an office, and so on. 
     The temperature of a room is often adjusted by using an air conditioner. Thus, appropriate control of air conditioners can save energy. 
     In the meantime, Office Automation (OA) equipment such as an image forming apparatus and a personal computer has recently been installed in business offices. Techniques for energy saving are also applied to such OA equipment. For example, according to a sleep mode technique, if no operation has been carried out in OA equipment for a preset time period, a hard disk and a display of the OA equipment stops operating temporarily, which reduces power consumption of the OA equipment. 
     There is proposed a method for controlling the temperature of a room where both an image forming apparatus and air-conditioning equipment (air conditioner) are installed. An example of the method is given below. 
     A home server controls an image forming apparatus and an air conditioner collectively. The image forming apparatus reads a print job quantity and transmits it to the air conditioner. The air conditioner cools and warms a room in response to the print job quantity. The air conditioner detects a temperature and humidity in the room and transmits the detected result to the image forming apparatus. The image forming apparatus controls a drive fan, a condensation preventing heater, and a dehumidification heater in the apparatus and adjusts a temperature and humidity in the apparatus based on the temperature and the humidity in the room (see the English abstract of Japanese Laid-open Patent Publication No. 2003-186373). 
     According to the method, it is necessary for the home server to manage the air conditioner. In recent years, there have been proposed electrical appliances having a function to perform communication with another device via a network, i.e., intelligent home appliances. However, the widespread use of such intelligent home appliances is yet to come. At present, the vast majority of electrical appliances have no communication function. In view of this, it probably takes a little time before the foregoing method is widely used. 
     On the other hand, almost all of image forming apparatuses have recently been equipped with a communication function. Further, some techniques for controlling an image forming apparatus by using a server become widespread. 
     SUMMARY 
     The present disclosure is directed to solve the problems pointed out above, and therefore, an object of an embodiment of the present invention is to achieve energy conservation in offices and so on without direct control of an air-conditioning system such as an air conditioner. 
     In one aspect of the present invention, an apparatus for assigning a print job includes a detector configured to detect an ambient temperature of each of a plurality of areas, said each of the areas including at least one printer and at least one air conditioning system; a selection portion configured to select a printer included in a suitable area of the areas, the suitable area being an area where the ambient temperature detected is lower than a predetermined temperature; and an issuing portion configured to give a print job to the printer selected. 
     Preferably, the selection portion may select a printer included in an area, of the areas, where the ambient temperature detected is lowest with reference to a predetermined temperature. 
     In another aspect of the present invention, an apparatus for assigning a print job includes a detector configured to detect an ambient temperature of each of a plurality of areas, said each of the areas including at least one printer and at least one air conditioning system; an estimating portion configured to estimate an ambient temperature of each of the areas for a case where a printer included in said each of the areas finishes executing a print job, the ambient temperature being estimated based on the ambient temperature detected and characteristics of the printer; a selection portion configured to select a printer included in a suitable area of the areas, the suitable area being an area where the ambient temperature estimated is lower than a predetermined temperature; and an issuing portion configured to give a print job to the printer selected. 
     Preferably, the selection portion may select a printer included in an area, of the areas, where the ambient temperature detected is lowest with reference to a predetermined temperature. 
     In yet another aspect of the present invention, an apparatus for assigning, in order, P print jobs wherein P represents 2 or more includes a detector configured to detect an ambient temperature of each of a plurality of areas, said each of the areas including at least one printer and at least one air conditioning system; an estimating portion configured to estimate, when a Q-th print job out of the P print jobs is assigned wherein Q represents a number in a range from 1 to P inclusive, an ambient temperature of each of the areas for a case where a printer included in said each of the areas finishes executing a print job earlier than a (Q−1)-th print job assigned to the printer and the printer finishes executing the Q-th print job, the ambient temperature being estimated based on the ambient temperature detected and characteristics of the printer; a selection portion configured to select, as a target printer to which the Q-th print job is assigned, a printer included in an area, of the areas, where the ambient temperature estimated is the lowest; and an issuing portion configured to give the Q-th print job to the printer selected. 
     These and other characteristics and objects of the present invention will become more apparent by the following descriptions of preferred embodiments with reference to drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing an example of the overall configuration of a printing system. 
         FIG. 2  is a diagram showing an example of the hardware configuration of an image forming apparatus. 
         FIG. 3  is a diagram showing an example of the hardware configuration of a print server. 
         FIG. 4  is a diagram showing an example of the functional configuration of a print server. 
         FIG. 5  is a graph showing an example of general change in ambient temperature and in output of an air conditioner. 
         FIG. 6  is a flowchart depicting an example of the flow of job execution apparatus determination processing. 
         FIGS. 7A-7D  are diagrams showing an example of a preset temperature, an ambient temperature, and a temperature difference in each area. 
         FIGS. 8A and 8E  are diagrams showing an example of an estimated rise in ambient temperature if a print job is executed in each area. 
         FIG. 9  is a flowchart depicting an example of the flow of the entire processing performed by a print server. 
         FIG. 10  is a flowchart depicting a modification of the flow of job execution apparatus determination processing. 
         FIG. 11  is a flowchart depicting a modification of the flow of job execution apparatus determination processing. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a diagram showing an example of the overall configuration of a printing system  100 ;  FIG. 2  is a diagram showing an example of the hardware configuration of an image forming apparatus  1 ;  FIG. 3  is a diagram showing an example of the hardware configuration of a print server  2 ; and  FIG. 4  is a diagram showing an example of the functional configuration of the print server  2 . 
     Referring to  FIG. 1 , the printing system  100  is configured of a plurality of image forming apparatuses  1 , the print server  2 , at least one terminal  3 , a communication line  4 , and so on. 
     The printing system  100  is a system to print an image onto paper. The printing system  100  is installed in a facility of an organization such as a corporation and a public office, and therefore, is used by members of the organization. In short, the members of the organization are users of the printing system  100 . 
     A facility space (a certain floor, for example) of the organization is divided into a plurality of areas (regions)  5 . Each of the areas  5  has one air conditioner installed therein. One area  5  has a size which allows an air conditioner installed therein to control an ambient temperature of the area  5 . Two areas  5  adjacent to each other may or may not be partitioned. Each of the areas  5  has one image forming apparatus  1  installed therein. 
     The following description provides an example in which a facility space is divided into four areas. The areas  5  may be described separately as an “area  51 ”, “area  52 ”, “area  53 ”, and “area  54 ”. Further, the image forming apparatuses  1  installed in the areas  51 ,  52 ,  53 , and  54  are referred to as an “image forming apparatus  11 ”, “image forming apparatus  12 ”, “image forming apparatus  13 ”, and “image forming apparatus  14 ”, respectively. 
     Each of the areas  5  is given one unique area identifier EC. Likewise, each of the image forming apparatuses  1  is given one unique device identifier DC. The area identifier EC of a certain area  5  and the device identifier DC of the image forming apparatus  1  installed in the area  5  are associated with each other and registered in the print server  2 . The device identifier DC may be a network address such as an Internet Protocol (IP) address or a Media Access Control (MAC) address. 
     The image forming apparatuses  1 , the print server  2 , and the terminals  3  are capable of conducting communication with one another via the communication line  4 . Examples of the communication line  4  are a Local Area Network (LAN), the Internet, a dedicated line, and a public line. 
     The image forming apparatus  1  is a processing apparatus in which various functions such as copying, scanning, faxing, and network printing are consolidated. The image forming apparatus  1  is sometimes called a “multifunction device” or a “Multi-Functional Peripheral (MFP)”. 
     The “network printing” is a function to receive image data from a terminal such as a personal computer and to print an image onto paper. The network printing function is sometimes called a “network printer function” or “PC printing function”. In the printing system  100 , however, image data is sent from the terminal  3  through the print server  2  to the image forming apparatus  1  instead of being sent directly from the terminal  3  to the image forming apparatus  1 . The detailed description is provided later. 
     As shown in  FIG. 2 , the image forming apparatus  1  is configured of a Central Processing Unit (CPU)  10   a , a Random Access Memory (RAM)  10   b , a Read Only Memory (ROM)  10   c , a hard disk  10   d , an operating panel  10   e , a scanner unit  10   f , a printer unit  10   g , a network interface  10   h , a modem  10   i , a temperature sensor  10   j , a variety of control circuits, and so on. 
     The network interface  10   h  performs communication with the print server  2  and the terminal  3  in accordance with a protocol such as Transmission Control Protocol/Internet Protocol (TCP/IP). An example of the network interface  10   h  is a Network Interface Card (NIC). 
     The modem  10   i  is a device to send and receive image data, based on a protocol such as G3, with other fax terminals. 
     The scanner unit  10   f  serves to optically read out an image such as characters, symbols, photographs, charts, illustrations, and the like that are recorded on a sheet of paper, and to generate image data thereof. 
     The printer unit  10   g  prints, onto paper, an image read out by the scanner unit  10   f  and an image indicated in data sent by the print server  2 , the terminal  3 , or a fax terminal. 
     The operating panel  10   e  is configured of a touch-sensitive panel display, a numerical keypad, and so on. The touch-sensitive panel display displays, for example, a screen for presenting messages or instructions to a user, a screen for allowing a user to input processing types and conditions desired by him/her, and a screen showing the results of processing performed by the CPU  10   a . A user operates the touch-sensitive panel display or the numerical keypad while looking at these screens to enter information and commands to the image forming apparatus  1 . 
     The temperature sensor  10   j  serves to measure an ambient temperature of an area where the image forming apparatus  1  including the temperature sensor  10   j  itself is installed. 
     The ROM  10   c  or the hard disk  10   d  has operating system, middleware, and so on installed therein, as software for implementing the functions discussed above. The ROM  10   c  or the hard disk  10   d  also has installed therein an ambient temperature replying application for informing the print server  2  of an ambient temperature measured by the temperature sensor  10   j  in response to an inquiry from the print server  2 . These pieces of software are loaded into the RAM  10   b  as needed and executed by the CPU  10   a.    
     The print server  2  provides a service of assigning print jobs sent from the terminal  3  to any of the image forming apparatuses  1 . Referring to  FIG. 3 , the print server  2  is configured of a CPU  20   a , a RAM  20   b , a ROM  20   c , a hard disk  20   d , a network interface  20   e , and so on. 
     The network interface  20   e  is an NIC performing communication with the image forming apparatus  1  and the terminal  3  in accordance with a protocol such as TCP/IP. 
     The ROM  20   c  or the hard disk  20   d  has installed therein operating system, middleware, and an application for assigning print jobs. Thanks to the application, the functions of a characteristic data storage portion  201 , a job data receiving portion  202 , an execution apparatus determination portion  203 , an ambient temperature data obtaining portion  204 , a job execution instructing portion  205 , and so on all of which are shown in  FIG. 4  are implemented. 
     These pieces of software are loaded into the RAM  20   b  as needed and executed by the CPU  20   a . The processing described later with reference to  FIGS. 6 ,  9 ,  10 , and  11  is also implemented by operation and control by the CPU  20   a.    
     The terminal  3  is a client for a user to use a printing service provided by the image forming apparatus  1 . The terminal  3  may be a personal computer, a Personal Digital Assistant (PDA), or a smartphone, for example. The terminal  3  has installed therein a printer driver for the image forming apparatus  1 . 
     The terminal  3  may be installed in any one of the areas  5  or at a site other than the areas  5 . 
       FIG. 5  is a graph showing an example of general change in ambient temperature and in output of an air conditioner;  FIG. 6  is a flowchart depicting an example of the flow of job execution apparatus determination processing;  FIGS. 7A-7D  are diagrams showing an example of a preset temperature TS, an ambient temperature TP, and a temperature difference TD in each of the areas  51 - 54 ; and  FIGS. 8A and 8B  are diagrams showing an example of an estimated rise in ambient temperature if a print job is executed in each of the areas  53  and  54 . 
     Descriptions are provided below, with reference to  FIG. 6  and so on, of the processing performed by the image forming apparatus  1 , the print server  2 , and the terminal  3  in order to assign print jobs. 
     The characteristic data storage portion  201  of the print server  2  stores, therein, characteristic data  6 A for each of the areas  5 . The characteristic data  6 A shows various characteristics of the corresponding area  5 . In particular, according to this embodiment, the characteristic data  6 A shows a preset temperature TS of an air conditioner installed in the corresponding area  5 , and an area identifier EC for identifying the area  5 . For example, characteristic data  6 A for the area  51  shows a preset temperature TS of an air conditioner installed in the area  51 . These sets of characteristic data  6 A are stored in advance in the characteristic data storage portion  201 . 
     In general, an air conditioner operates in such a manner that the surrounding temperature becomes equal to a preset temperature. As shown in  FIG. 5 , the air conditioner for cooling performs high-power operation while the surrounding temperature is higher than the preset temperature. On the other hand, the air conditioner for cooling stops or performs low-power operation while the surrounding temperature is lower than the preset temperature. 
     A user prepares, in the terminal  3 , image data on an image to be printed. The image data can be prepared by using an application such as word processing software or rendering software to create an image. Alternatively, web page data may be downloaded from a web site on the Internet, and the web page data may be used as the image data. 
     The user specifies print job conditions such as the set of prints, and then enters a print command into the terminal  3 . 
     In response to the operation, the terminal  3  creates print data  6 B, for example, by causing the driver to convert the image data into data for Page Description Language (PDL). The terminal  3  then sends, to the print server  2 , the print data  6 B together with conditions data  6 C indicating the print job conditions specified by the user. 
     With the print server  2 , the job data receiving portion  202  receives the print data  6 B and the conditions data  6 C from the terminal  3 . 
     When the print data  6 B and the conditions data  6 C are received, the execution apparatus determination portion  203  determines an image forming apparatus  1  suitable for executing a print job based on the print data  6 B and the conditions data  6 C. At this time, the ambient temperature data obtaining portion  204  performs processing for obtaining, from the individual image forming apparatuses  1 , ambient temperature data for the individual areas  5 . 
     Descriptions are provided below of the details of processing performed by the execution apparatus determination portion  203  and the ambient temperature data obtaining portion  204 , with reference to the flowchart of  FIG. 6 . 
     When the print data  6 B and the conditions data  6 C are received, the execution apparatus determination portion  203  instructs the ambient temperature data obtaining portion  204  to obtain ambient temperature data. In accordance with the instructions, the ambient temperature data obtaining portion  204  requests data on current ambient temperature from the image forming apparatus  11  installed in the area  51  that is the first area  5 , and obtains the data therefrom (Step # 702 ). 
     At this time, in the image forming apparatus  11 , the following processing is carried out based on the ambient temperature replying application. The temperature sensor  10   j  measures the current ambient temperature TP. The CPU  10   a  creates ambient temperature data  6 D indicating the ambient temperature TP obtained by the measurement and an area identifier EC of the area  51 . Then, the ambient temperature data  6 D is sent to the print server  2  through the network interface  10   h.    
     The execution apparatus determination portion  203  calculates a temperature difference TD by subtracting the preset temperature TS indicated in the characteristic data  6 A on the area  51  from the ambient temperature TP indicated in the ambient temperature data  6 D sent from the image forming apparatus  11  (Step # 703 ). 
     Likewise, as for the second through fourth areas  5 , the execution apparatus determination portion  203  and the ambient temperature data obtaining portion  204  receive ambient temperature data  6 D from each of the image forming apparatus  12 - 14 , and calculates the individual temperature differences TD by subtracting the individual preset temperatures TS from the individual ambient temperatures TP (Steps # 702 -# 705 ). 
     The execution apparatus determination portion  203  then extracts, from the temperature differences TD for the areas  51 - 54 , one having the smallest value, and determines that the image forming apparatus  1  installed in one of the areas  5  corresponding to the extracted temperature difference TD is an image forming apparatus  1  suitable for executing the print job (Step # 706 ). In short, the execution apparatus determination portion  203  determines that an apparatus to which the print job is to be given is the image forming apparatus  1  installed in the area  5  corresponding to the extracted temperature difference TD. 
     It is assumed that, for example, the temperature differences TD 1 -TD 4  shown in  FIGS. 7A-7D  are obtained as the temperature differences TD for the areas  51 - 54 , respectively. In the illustrated example, the temperature difference TD 3  has the smallest value. In other words, referring to  FIG. 7C , the ambient temperature TP 3  is lower than the preset temperature TS 3 , and the difference TD 3  therebetween has the largest value in the illustrated example. Thus, the execution apparatus determination portion  203  determines that the image forming apparatus  1  in the area  53 , i.e., the image forming apparatus  13 , is the image forming apparatus  1  suitable for executing the print job. 
     The job execution instructing portion  205  instructs the image forming apparatus  1  determined by the execution apparatus determination portion  203  to execute the print job, and sends the print data  6 B and the conditions data  6 C for the print job to the image forming apparatus  1  determined. 
     When receiving the print data  6 B and the conditions data  6 C, the image forming apparatus  1  executes the print job based on the print data  6 B and the conditions data  6 C. Thereby, an image is printed onto a sheet of paper. 
     According to the foregoing processing, if the temperature differences TD for the individual areas  5  are the temperature differences TD 1 -TD 4  shown in  FIGS. 7A-7D , then the image forming apparatus  13  executes the print job. The operation of the image forming apparatus  13  develops heat therefrom, so that an ambient temperature in the area  53  rises. 
     The area  53  has the temperature difference TD having the smallest value in all the areas  5 . Even if the ambient temperature in the area  53  rises as shown in  FIG. 8A  due to the heat caused by the execution of the print job, the ambient temperature in the area  53  is most likely to be still lower than the preset temperature compared to the cases of the other areas. 
     On the other hand, if the image forming apparatus  1  in one of the areas  5  other than the area  53 , e.g., in the area  54 , executes a print job, then the ambient temperature TP in the area  54  rises as shown in  FIG. 8B  and the temperature difference from the preset temperature TS becomes larger. This causes the air conditioner for cooling installed in the area  54  to perform high-power operation for a longer period of time. 
     As for the case of air conditioner for heating, if the image forming apparatus  1  in the area  53  executes a print job, then the ambient temperature TP in the area  53  is increased to reach the preset temperature TS. Accordingly, the heat generated by printing is utilized to shorten a time period during which the air conditioner in the area  53  performs high-power operation. 
     In this way, the image forming apparatus  1  in the area  5  corresponding to the smallest temperature difference TD is caused to execute a print job. This enables reduction in power consumption by all the air conditioners in the areas  51 - 54  during a certain period of time. 
       FIG. 9  is a flowchart depicting an example of the flow of the entire processing performed by the print server  2 . 
     The following is a description of the flow of the entire processing performed by the print server  2  to allocate print jobs, with reference to the flowchart of  FIG. 9 . 
     When receiving print data  6 B and conditions data  6 C from the terminal  3  (Step # 711 ), the print server  2  determines an image forming apparatus  1  suitable for executing a print job corresponding to the print data  6 B and the conditions data  6 C (Step # 712 ). How to determine such an image forming apparatus  1  is the same as that described above with reference to  FIG. 6 . 
     The print server  2  then instructs the image forming apparatus  1  thus determined to execute the print job, and transfers the print data  6 B and the conditions data  6 C for the print job to the image forming apparatus  1  determined (Step # 713 ). 
     In this embodiment, an air conditioning system such as an air conditioner is not controlled directly, an image forming apparatus  1  suitable for executing a print job is determined, and the print job is given to the image forming apparatus  1  determined. This saves energy used in offices and so on. 
     Modifications of this embodiment are given in order below. 
     [Method for Determining Image Forming Apparatus  1  in Combination with User&#39;s Selection] 
     According to the determination method in the foregoing embodiment, the image forming apparatus  1  to execute a print job is an image forming apparatus  1  installed in an area  5  corresponding to the smallest temperature difference TD. Instead of this, however, another arrangement is possible in which areas  5  corresponding to the temperature difference TD having a constant value (minus 2 degrees, for example) or less are selected from among all the areas  5 , and a user is informed of the image forming apparatuses  1  installed in the selected areas  5 . The user then selects any one of the image forming apparatuses  1  thus informed, and the image forming apparatus  1  selected may be caused to execute a print job. 
     [Time to Obtain Characteristic Data  6 A and Ambient Temperature Data  6 D] 
     In the forgoing embodiment, the print server  2  stores, in advance, characteristic data  6 A in the characteristic data storage portion  201 . Further, in the foregoing embodiment, ambient temperature data  6 D is obtained every time when the need arises to cause any one of the image forming apparatuses  1  to execute a print job. Instead of this, however, the characteristic data  6 A and the ambient temperature data  6 D may be obtained at the following time. 
     The individual air conditioners in the areas  5  are structured to have a communication function. When a preset temperature TS of an air conditioner is changed, the air conditioner sends data indicating the post-change preset temperature TS and an identifier of the air conditioner to the print server  2 . The identifier of the air conditioner is associated with an area identifier EC of the area  5  where the corresponding air conditioner is installed. Upon the receipt of the data, the print server  2  stores the same into the characteristic data storage portion  201  as characteristic data  6 A for the corresponding area  5 . Alternatively, it is possible for the print server  2  to inquire the current preset temperature TS from the air conditioner in each of the areas  5  at regular time intervals. If the current preset temperature TS is changed from the previous value, then the characteristic data  6 A may be updated accordingly. 
     On the other hand, each of the image forming apparatuses  1  measures an ambient temperature TP of the corresponding installation area at regular time intervals, and informs the print server  2  of data indicating the ambient temperature TP measured and an area identifier EC of the area  5  that is the installation location of the corresponding image forming apparatus  1 . Upon the receipt of the data, the print server  2  stores the data as ambient temperature data  6 D of the corresponding area  5  into a predetermine database. Alternatively, it is possible for the print server  2  to inquire the current ambient temperature TP from the image forming apparatus  1  in each of the areas  5  at regular time intervals. If the current ambient temperature TP is changed from the previous value, then the ambient temperature data  6 D may be updated accordingly. 
     Yet alternatively, an air conditioner rather than the image forming apparatus  1  may measure an ambient temperature TP in the corresponding area  5 , and inform the print server  2  of the measurement result. 
     [Method for Determining Image Forming Apparatus  1  in Consideration of Rise in Ambient Temperature Caused by Execution of Print Job] 
       FIG. 10  is a flowchart depicting a modification of the flow of job execution apparatus determination processing. 
     When an image forming apparatus  1  executes a print job, an ambient temperature therearound increases. How much the ambient temperature increases depends on the features and conditions of the image forming apparatus  1 . In particular, as for the case of the air conditioner for cooling, a smaller rise in ambient temperature is more preferable in order to reduce the power consumption. 
     In view of this, the print server  2  determines an image forming apparatus  1  to execute a print job by using the following method instead of the method described earlier with reference to  FIG. 6  and so on. 
     The characteristic data storage portion  201  stores, in advance, characteristic data  6 E rather than the characteristic data  6 A for each of the areas  5 . The characteristic data  6 E indicates, in addition to an area identifier EC of the corresponding area  5  and a preset temperature TS of an air conditioner in the corresponding area  5 , a warm-up increased temperature TW and a printing increased temperature TJ of the image forming apparatus  1  in the corresponding area  5 . 
     The warm-up increased temperature TW is a temperature that is increased by starting (warming up) the printer unit  10   g  in the area  5  corresponding to the area identifier EC. The warm-up increased temperature TW may be calculated in advance through the following method, for example. First, an ambient temperature TM 1  under a state where the printer unit  10   g  does not operate is measured. The printer unit  10   g  is started promptly and an ambient temperature TM 2  after the start-up is measured. The measurement may be made by the temperature sensor  10   j  or the air conditioner. The same applies to the descriptions hereinafter. Then, the ambient temperature TM 1  is subtracted from the ambient temperature TM 2 . The resultant is regarded as the warm-up increased temperature TW. 
     The printing increased temperature TJ is a temperature that is increased by printing out an image onto a sheet of paper. The printing increased temperature TJ may be calculated in advance through the following method, for example. First, the printer unit  10   g  is started and an ambient temperature TN 1  under a state where the printer unit  10   g  is idle is measured. Without delay, the printer unit  10   g  is caused to execute a print job of printing out images onto N sheets of paper, and an ambient temperature TN 2  after the execution of the print job is measured. Then, the ambient temperature TN 1  is subtracted from the ambient temperature TN 2 , and the resultant is divided by N. A value obtained by the subtraction and division is regarded as the printing increased temperature TJ. 
     The warm-up increased temperature TW and the printing increased temperature TJ are calculated in advance for each of the image forming apparatuses  1 . 
     Another arrangement is possible in which, every time a print job is executed, records of the ambient temperatures TM 1 , TM 2 , TN 1 , and TN 2 , and the number of prints N are kept, and the warm-up increased temperature TW and the printing increased temperature TJ are recalculated based on the records. Yet another arrangement is possible in which, at certain time intervals, the warm-up increased temperature TW and the printing increased temperature TJ are recalculated by using the foregoing records associated with print jobs executed during the certain time period. 
     When the job data receiving portion  202  receives print data  6 B and conditions data  6 C, the execution apparatus determination portion  203  and the ambient temperature data obtaining portion  204  determine an image forming apparatus  1  suitable for executing a print job based on the print data  6 B and the conditions data  6 C in a manner as shown in  FIG. 10 . 
     The execution apparatus determination portion  203  instructs the ambient temperature data obtaining portion  204  to obtain data on area conditions. In response to the instructions, the ambient temperature data obtaining portion  204  requests data on current conditions of the area  51  from the image forming apparatus  11  installed in the area  51  that is the first area  5 , and obtains the data from the image forming apparatus  11  (Step # 722 ). 
     At this time, in the image forming apparatus  11 , the ambient temperature replying application is implemented to carry out the processing described below. Conditions data  6 F is created instead of the ambient temperature data  6 D, and the conditions data  6 F is then sent to the print server  2 . 
     The temperature sensor  10   j  measures the current ambient temperature TP. The CPU  10   a  creates the conditions data  6 F. As with the ambient temperature data  6 D, the conditions data  6 F indicates the ambient temperature TP obtained by the measurement and the area identifier EC of the area  51 . The conditions data  6 F further contains a start flag FG. The start flag FG shows whether or not the printer unit  10   g  is running. The start flag FG indicates “1” if the printer unit  10   g  is not running. The start flag FG indicates “0” if the printer unit  10   g  is running. 
     Then, the conditions data  6 F is sent to the print server  2  via the network interface  10   h.    
     The execution apparatus determination portion  203  uses the equation (1) below to estimate, based on the conditions data  6 F sent from the image forming apparatus  11  and the characteristic data  6 E for the image forming apparatus  11  stored in the characteristic data storage portion  201 , an ambient temperature in the area  51  after execution of the print job (such a temperature is hereinafter referred to as a “post-execution temperature TF”) (Step # 723 ).
 
 TF=TP+TW·FG+TJ·CP   (1)
 
where “TP” and “FG” represent the ambient temperature TP and the start flag FG respectively indicated in the conditions data  6 F sent from the image forming apparatus  11 , “TW” and “TJ” represent the warm-up increased temperature TW and the printing increased temperature TJ respectively indicated in the characteristic data  6 A for the image forming apparatus  11 , and “CP” represents the total number of sheets to be outputted by executing the print job this time. The value of “CP” can be determined based on the print data  6 B and the conditions data  6 C. It is assumed that, for example, three pages of images are indicated in the print data  6 B, and the set of prints indicated in the conditions data  6 C is five sets. In such a case, the value of “CP” is fifteen by the following equation:
 
 CP= 3×5=15.
 
     Likewise, as for the second through fourth areas  5 , the execution apparatus determination portion  203  and the ambient temperature data obtaining portion  204  receive conditions data  6 F from each of the image forming apparatuses  12 - 14 , and uses the equation (1) provided above to calculate a post-execution temperature TF based on the characteristic data  6 A and the conditions data  6 F for each of the image forming apparatuses  12 - 14  (Steps # 722 -# 725 ). 
     The execution apparatus determination portion  203  then extracts, from the post-execution temperatures TF for the areas  51 - 54 , one having the smallest value, and determines that the image forming apparatus  1  installed in one of the areas  5  corresponding to the extracted post-execution temperature TF is an image forming apparatus  1  suitable for executing the print job (Step # 726 ). 
     [Allocating Print Jobs Based on Humidity] 
     In the foregoing embodiment and the modifications thereof, a plurality of image forming apparatuses  1  are sometimes deemed as candidates for a target device to which one print job is to be allocated. 
     In such a case, one of the image forming apparatuses  1  may be selected as a target device to which the print job is to be given in the following manner. 
     A humidity sensor is provided in advance in each of the image forming apparatuses  1 . If a plurality of image forming apparatuses  1  are regarded as candidates for a target device to which one print job is to be given, then the execution apparatus determination portion  203  inquires of each of the image forming apparatuses  1  as to humidity. In response to the inquiry, the individual image forming apparatuses  1  measure humidity and inform the execution apparatus determination portion  203  of the measurement results. The execution apparatus determination portion  203  then selects the image forming apparatus  1  which measured the lowest humidity as the target device to which the print job is to be given. 
     The following arrangement is also possible: Humidity sensors of the individual image forming apparatuses  1  are controlled to measure humidity at regular intervals, and to inform the print server  2  of the measurement results. The print server  2  keeps records of the humidity in the database, and a target device to which a print job is to be given is determined based on the records. 
     The higher the humidity is, the more likely paper curls and a paper jam occurs. Further, the higher the humidity is, the fainter or lighter the print is due to condensation. In this way, a target device to which a print job is to be given is determined in consideration of humidity, which results in obtaining a printed image having a high quality. 
     [Method for Determining Image Forming Apparatus  1  Based on Difference from Common Reference Temperature] 
     In the foregoing embodiment and the modifications thereof, a preset temperature TS is set for each of the areas  5 . Instead of this, however, a reference temperature TH common to all the areas  5  may be set, and an image forming apparatus  1  as a target device to which a print job is to be given may be determined in the following manner. 
     The execution apparatus determination portion  203  selects image forming apparatuses  1  in areas  5  where the ambient temperature TP is lower than the reference temperature TH. The image forming apparatuses  1  thus selected are presented to a user. The user selects one of the image forming apparatuses  1  presented. In accordance with the selection, a print job is given to the image forming apparatus  1  selected by the user. 
     Another configuration is possible in which the execution apparatus determination portion  203  gives a print job to an image forming apparatus  1  in an area  5  where the ambient temperature TP is the lowest in all the areas  5 . 
     [Case where a Plurality of Print Jobs are Received Successively Around the Same Time] 
       FIG. 11  is a flowchart depicting a modification of the flow of job execution apparatus determination processing. 
     The print server  2  sometimes receives, from one or more terminals  3 , a plurality of print jobs one after another around the same time. In such a case, every time one print job is received, the print job may be allocated to an image forming apparatus  1  in the manner as discussed in the foregoing embodiment and modifications thereof. However, the following job allocation is also possible. 
     When the job data receiving portion  202  receives a print job, more specifically, when the job data receiving portion  202  receives print data  6 B and conditions data  6 C, the execution apparatus determination portion  203  waits for another print job to be sent for a preset time period, e.g., one minute, without determining an image forming apparatus  1  to which the already-received print job is to be given. 
     If a plurality of (P) jobs are received before the lapse of the preset time period, then the execution apparatus determination portion  203  determines to which image forming apparatuses the print jobs received during the preset time period are allocated in the manner as shown in  FIG. 11 . 
     The execution apparatus determination portion  203  instructs the ambient temperature data obtaining portion  204  to obtain ambient temperature data  6 D for each of the areas  5 . In response to the instructions, the ambient temperature data obtaining portion  204  requests ambient temperature data  6 D from each of the image forming apparatuses  1  in the areas  5 , and obtains the ambient temperature data  6 D therefrom (Step # 731 ). 
     The execution apparatus determination portion  203  determines, for each of the areas  5 , a predicted temperature TQ that is an ambient temperature expected for the case where the print job is finished (Step # 732 ). The initial value of the predicted temperature TQ is an ambient temperature TP indicated in ambient temperature data  6 D received from an image forming apparatus  1  in an area  5  corresponding to the predicted temperature TQ. 
     The execution apparatus determination portion  203  assigns, among yet-to-be-assigned print jobs, a print job by which the highest amount of heat is produced to an image forming apparatus  1  in an area  5  corresponding to the lowest predicted temperature TQ (Step # 734 ). Note that the print job by which the highest amount of heat is produced is a print job by which the largest number of prints are produced. 
     The execution apparatus determination portion  203  then calculates a temperature-to-rise, i.e., how many degrees of temperature is to rise for a case where the image forming apparatus  1  executes the print job, and adds the temperature-to-rise to the predicted temperature TQ for the area  5  where the image forming apparatus  1  is installed (Step # 735 ). As discussed above, the temperature-to-rise can be calculated based on the warm-up increased temperature TW, the printing increased temperature TJ, and the number of prints indicated in the characteristic data  6 E for the image forming apparatus  1 . 
     Likewise, as for the remaining print jobs, the execution apparatus determination portion  203  performs the processing of Step # 734  and Step # 735 , and assigns a print job by which the highest amount of heat is produced to the image forming apparatus  1  in an area  5  corresponding to the lowest predicted temperature TQ. 
     In this modification, print jobs are assigned in order of decreasing heat produced by executing a print job. However, print jobs are assigned in different order. For example, print jobs may be assigned in order of increasing heat produced by executing a print job, or, alternatively, in order in which the print jobs were received by the print server  2 . 
     [Case where a Plurality of Image Forming Apparatuses  1  are Installed in One Area  5 ] 
     In the foregoing embodiment and the modifications thereof, the case is described in which one image forming apparatus  1  is installed in one area  5 . If a plurality of image forming apparatuses  1  are installed in one area  5 , the print server  2  may assign a print job to one of the image forming apparatuses  1  in the following manner. 
     One image forming apparatus  1  is selected in advance for each of the areas  5  as a representative image forming apparatus  1 . The print server  2  sends and receives the foregoing sets of data with the representative image forming apparatuses  1 , and determines an area  5  that is suitable for a print job to be executed. The print server  2  then gives the print job to any one of the image forming apparatuses  1  installed in the determined area  5 . To be specific, the print server  2  sends print data  6 B and conditions data  6 C for the print job to any one of the image forming apparatuses  1 . For example, the print server  2  gives the print job to one of the image forming apparatuses  1  selected by the user. Alternatively, the print server  2  gives the print job to an image forming apparatus  1  which produces the least heat by executing the print job. In such a case, heat developed by warm-up is also taken in consideration. 
     [Other] 
     In the foregoing embodiment and the modifications thereof, the case is described in which an air conditioner, i.e., an air-conditioning system having both cooling and heating functions is located in each of the areas  5 . The present invention is also applicable to a case in which an air-conditioning system having only one of the functions is located. 
     In the foregoing embodiment and the modifications thereof, the case is described in which an image forming apparatus  1  having many functions is installed in each of the areas  5 . The present invention is also applicable to a case in which an apparatus having only a copy function, or an apparatus having only a PC printing function is located. 
     In the foregoing embodiment and the modifications thereof, the print server  2  determines an image forming apparatus  1  to execute a print job. Instead of this, however, the terminal  3  may make such a determination. 
     In the foregoing embodiment and the modifications thereof, how much heat is to be produced due to execution of a print job is estimated based on the number of sheets of output paper. Alternatively, the estimate may be made in consideration of the following conditions: whether the print job involves color printing or not; the size of paper; and whether the print job involves double-sided printing. 
     It is to be understood that the configurations of the printing system  100 , the image forming apparatus  1 , and the print server  2 , the constituent elements thereof, the content and order of the processing, the configuration of data, and the like can be appropriately modified without departing from the spirit of the present invention. 
     While example embodiments of the present invention have been shown and described, it will be understood that the present invention is not limited thereto, and that various changes and modifications may be made by those skilled in the art without departing from the scope of the invention as set forth in the appended claims and their equivalents.