Abstract:
An image forming apparatus includes a communicating unit ( 123 ) that performs communication with an external apparatus ( 200 ), a recording unit ( 97 ) that stores image information, an image processing unit ( 96 ) that performs image processing, and a control unit ( 91 ) that performs control to secure the image processing unit from the external apparatus via the communicating unit, when a request signal for performing processing of the image information is received, if the image processing unit can be secured, convert a file format by expanding the image information and compressing the image information again using the image processing unit secured and transfer the image information converted via the communicating unit, and, if the image processing unit cannot be secured, transmit an indication that the image processing unit cannot be secured and the image information before the conversion to the external apparatus via the communicating unit.

Description:
BACKGROUND OF THE INVENTION 
   Recently, according to the improvement of performance of image forming apparatuses such as a digital copying machine, an integrated digital apparatus having not only a copying function but also a function of a printer is developed and spread. Such image forming apparatuses have a full network function and can perform various kinds of image processing using a client computer via a network. 
   A Patent Document 1 (JP-A-2004-320255) discloses an image processing apparatus to which a computer capable of executing image processing corresponding to an image processing command is connected. In the Patent Document 1, addition of an image processing command is permitted according to a file format at a conversion destination of read image data to distribute processing loads to the image processing apparatus. 
   However, in this Patent Document 1, since load distribution processing is performed only in the inside of the image processing apparatus by the addition of the command corresponding to the file format, there is a problem in that, for example, the processing is delayed when an image processing unit built in the image processing apparatus is in use. 
   BRIEF SUMMARY OF THE INVENTION 
   An embodiment of an image forming apparatus according to the invention is an image forming apparatus including: a communicating unit ( 123 ) that performs communication with an external apparatus ( 200 ); a recording unit ( 97 ) that stores image information; an image processing unit ( 96 ) that performs image processing; and a control unit ( 91 ) that performs control to secure the image processing unit from the external apparatus via the communicating unit, when a request signal for performing processing of the image information is received, if the image processing unit can be secured, converts a file format by expanding the image information and compressing the image information again using the image processing unit secured and transfers the image information converted via the communicating unit, and, if the image processing unit cannot be secured, transmits an indication that the image processing unit cannot be secured and the image information before the conversion to the external apparatus via the communicating unit. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a diagram for explaining an example of an internal structure of an image forming apparatus according to the invention; 
       FIG. 2  is a block diagram for explaining an example of an electrical structure of the image forming apparatus according to the invention; 
       FIG. 3  is an explanatory diagram showing an example of a system through a network in which the image forming apparatus according to the invention is used; 
       FIG. 4  is a block diagram showing an example of a structure of an information processing apparatus on the system according to the invention; 
       FIG. 5  is a flowchart showing an example of file conversion processing by the image forming apparatus and the information processing apparatus according to the invention; and 
       FIG. 6  is a flowchart showing another example of the file conversion processing by the image forming apparatus and the information processing apparatus according to the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   File conversion processing by an image forming apparatus and an information processing apparatus according to the invention will be hereinafter explained in detail using the drawings. 
   &lt;Image Forming Apparatus According to the Invention&gt; 
   (Mechanical Structure) 
   First, an example of a structure of an image forming apparatus according to the invention will be explained.  FIG. 1  is a diagram for explaining an internal structure of the image forming apparatus. This image forming apparatus  1  includes a color scanner unit  4  as an image scanning unit, a printer unit  6 , an auto document feeder (hereinafter abbreviated as ADF)  7 , and an operation panel  80  described later. 
   The scanner unit  4  has the ADF  7  thereon and includes an original placing stand  8  that is disposed to be opposed to the ADF  7  in a closed state and formed by transparent glass on which an original is set. Below the original placing stand  8 , an exposure lamp  25  that illuminates the original placed on the original placing stand  8  and a first mirror  26  that condenses light from the exposure lamp  25  on the original and bends reflected light from the original, for example, in a left direction with respect to the drawing are fixed to a first carriage  27 . 
   The first carriage  27  is arranged to be movable parallel to the original placing stand  8  and reciprocatingly moved below the original placing stand  8  by a not-shown scanning motor via a not-shown toothed belt and the like. 
   Further, below the original placing stand  8 , a second carriage  28  movable parallel to the original placing stand  8  is disposed. Second and third mirrors  30  and  31  that deflect reflected light from the original, which is deflected by the first mirror  26 , in order are attached to the second carriage  28  at a right angle to each other. The second carriage  28  is driven to follow the first carriage  27  by the toothed belt and the like that drive the first carriage  27  and is moved at speed half of that of the first carriage  27  in parallel to the original placing stand  8 . 
   Moreover, below the original placing stand  8 , a focusing lens  32  that focuses reflected light from a third mirror  31  on the second carriage  28  and a CCD (a photoelectric conversion element)  34  that receives and photoelectrically converts the reflected light focused by the focusing lens are disposed. The focusing lens  32  is disposed to be movable via a driving mechanism in a plane including an optical axis of the light deflected by the third mirror  31  and focuses the reflected light at a predetermined magnification by moving itself. The CCD  34  photoelectrically converts the reflected light made incident thereon and outputs an electric signal corresponding to the original read. 
   On the other hand, the printer unit  6  includes a laser exposure device  40  that acts as latent image forming means. The laser exposure device  40  includes a semiconductor laser as a light source, a polygon mirror as a scanning member that continuously deflects a laser beam emitted from the semiconductor laser, a polygon motor as a scanning motor that drives to rotate the polygon mirror at a predetermined number of revolutions, and an optical system that deflects the laser beam from the polygon mirror and leads the laser beam to a photoconductive drum  44  described later. 
   The printer unit  6  has a rotatable photoconductive drum  44  as an image bearing member disposed in substantially the center of an apparatus main body. The peripheral surface of the photoconductive drum  44  is exposed by the laser beam from the laser exposure device  40  and a desired electrostatic latent image is formed thereon. Around the photoconductive drum  44 , an electrifying charger  45  that charges the drum peripheral surface to a predetermined charge, a developing device unit  46  that supplies a toner as a developing agent to the electrostatic latent image formed on the peripheral surface of the photoconductive drum  44  and develops the electrostatic latent image at a desired image density, and a transfer charger  48  that transfers a toner image formed on the photoconductive drum  44  onto a sheet are arranged. 
   In a lower part in the apparatus main body, an upper cassette  52  and a lower cassette  54 , which can be drawn out from the apparatus main body, respectively, are disposed in a state in which the upper cassette  52  is provided on the lower cassette  54 . A large capacity feeder  55  is provided beside these cassettes. Above the large capacity feeder  55 , a sheet feeding cassette  57  also functioning as a manual feed tray  56  is detachably mounted. 
   A registration roller pair  65  is provided on an upstream side of the photoconductive drum  44 . The registration roller pair  65  corrects inclination of a copy sheet taken out, aligns the leading end of the toner image on the photoconductive drum  44  and the leading end of the copy sheet, and feeds the copy sheet to a transfer belt unit  49  at the same speed as moving speed of the peripheral surface of the photoconductive drum  44 . 
   In a front upper part of the apparatus main body, an operation panel  80  for inputting various copying conditions, a copy start signal for starting a copying operation, and the like is provided. As shown in, for example,  FIG. 2 , the operation panel  80  includes a print key  82 , a panel CPU  83 , and a liquid crystal display unit  84 . The print key  82  instructs start of copying. The liquid crystal display unit  84  displays the number of originals and the number of copies and performs display of a copying magnification and edition and various kinds of operation guidance. A touch panel is provided in this liquid crystal display unit  84 . 
   (Electrical Structure) 
   In a block diagram shown in  FIG. 2 , the image forming apparatus according to the invention includes a control unit constituted by three CPUs, namely, a main CPU (central processing unit)  91  in a main control unit  90 , a scanner CPU  100  of the color scanner unit  4 , and a printer CPU  110  of the color printer unit  6 . The main CPU  91  performs serial communication with the printer CPU  110  and issues an operation instruction and the printer CPU  110  returns a status. The main CPU  91  performs serial communication with the scanner CPU  100  and issues an operation instruction and the scanner CPU  100  returns a status to the main CPU  91 . 
   The operation panel  80  is connected to the main CPU  91 . The main control unit  90  includes the main CPU  91 , a ROM  92 , a RAM  93 , an NVM  94 , an image processing unit  96  that performs expansion, compression, and conversion processing, a page memory control unit  97 , a page memory  98 , a printer controller  99 , and an HDD  124 . 
   The main CPU  91  controls the entire main control unit  90 . The ROM  92  has a control program stored therein. The RAM  93  temporarily stores data. 
   The NVM (nonvolatile random access memory: nonvolatile RAM)  94  is a nonvolatile memory backed up by a battery (not shown). The NVM  94  holds data thereon when a power supply is turned off. 
   The page memory control unit  97  stores image data in the page memory  98  and reads out image data from the page memory  98 . The page memory  98  has an area enough for storing image data for plural pages. The page memory  98  is formed to be capable of storing, page by page, data obtained by compressing image data from the scanner unit  4 . Font data corresponding to print data is stored in a printer font ROM  121 . 
   The printer controller  99  includes the printer font ROM  121 . The printer controller  99  expands print data from an external apparatus  200  such as a personal computer into image data using font data stored in the printer font ROM  121  at resolution corresponding to data indicating resolution given to the print data via an input port  16 . An external interface  123  performs communication of various signals with the external apparatus  200 . Image information and the like are acquired by a FAX unit  85  as a facsimile and stored by the page memory  98  and the like. 
   The scanner unit  4  includes the scanner CPU  100  that controls the entire scanner unit  4 , a ROM  101  having a control program and the like stored therein, a RAM  102  for data storage, a CCD driver  103  that drives the CCD sensor  34 , a scanner motor driver  104  that controls rotation of a motor for moving the exposure lamp  25 , the mirrors  26 ,  30 , and  31 , and the like, and an image correcting unit  105  including an A/D conversion circuit for converting an analog signal from the CCD sensor  34  into a digital signal, a shading correction circuit for correcting fluctuation in a threshold level with respect to an output signal from the CCD sensor  34  due to variation in the CCD sensor  34 , a change in an ambient temperature, or the like, and a line memory for temporarily storing a digital signal subjected to shading correction from the shading correction circuit. 
   The printer unit  6  includes the printer CPU  110  that controls the entire printer unit  6 , a ROM  111  having a control program and the like stored therein, a RAM  112  for data storage, a laser driver  113  that turns on and off light emission (exposure) by a semiconductor laser, a polygon motor driver (a motor control device)  114  that controls rotation of a polygon motor of a laser unit, a sheet conveying unit  115  that controls conveyance of a sheet by a conveying path, a development process unit  116  that performs charging, development, and transfer using the electrifying charger  45 , the developing device unit  46 , and the transfer charger  48 , a fixing control unit  117  that controls a fixing device unit  60 , an option unit  118 , an output port  13 , the input port  16 , and an image forming apparatus  20  according to the embodiment of the invention. 
   The image processing unit  96  that performs expansion, compression, and conversion processing and the page memory  98  are connected to transmit and receive image data. The image correcting unit  105  and the image processing unit  96  are connected to transmit and receive image data. Similarly, the image correcting unit  105  and the color print control device  20  are connected to transmit and receive image data. The printer controller  99  and the image processing unit  96  are also connected to transmit and receive image data. 
   &lt;Image Forming System According to the Invention&gt; 
   As shown in  FIG. 3 , the image forming apparatus described above can perform image formation corresponding to operation by a user in cooperation with a client PC  200  and a server S via a network N such as the Ethernet (registered trademark). 
   (Information Processing Apparatus) 
   The client PC  200  or the like has, as shown in  FIG. 4 , an I/F unit  201  that can perform communication via the network N such as the Ethernet (registered trademark), an operation unit  202  such as a mouse and a keyboard, a processing unit  203  constituted by a CPU and the like, a storing unit  204  such as a hard disk and a detachable memory, and a display unit  205  such as a liquid crystal display. 
   According to an embodiment of the invention, in such an image forming system constituted by the information processing apparatus  200  and the client PC  200 , the server S, and the like communicating via the network N, it is possible to perform file conversion processing described later. 
   &lt;File Conversion Processing by the Image Forming Apparatus According to the Invention&gt; 
   File conversion processing in the image forming apparatus according to the invention will be explained in detail using flowcharts in  FIGS. 5 and 6 . 
   Documents are inputted to a hard disk of the page memory  98  or the like of the image forming apparatus  1  from plural input sources in the copy operation, print operation from the client PC, scan operation, and facsimile transmission and reception operation, and the like. However, a system for storing these documents is different depending on an input source. For example, documents inputted by the copy operation and the print operation are stored in formats suitable for printing. 
   In an application associated with the image forming apparatus  1 , image processing for converting the documents inputted from all of these input sources into a browsable format is necessary in downloading the documents to the client PC  200  and storing the documents as browsable file. 
   (Case in Which File Conversion Processing is Performed in the Image Forming Apparatus:  FIG. 5 ) 
   First, when a document desired to be acquired among documents stored in the page memory  98  or the like of the image forming apparatus  1  is selected and a request for processing of the document is received from a user, the application of the client PC  200  associated with the image forming apparatus  1  performs conversion processing for a file format in a procedure described later (step S 11 ). 
   Image Information to be Set as an Object 
   As image information of a document or the like stored in the page memory  98  or the like of the image forming apparatus  1 , there are following types. Some image information is set as an object of conversion of a file format and other image information is not set as an object. 
   The image information to be set as an object of the file conversion processing is, as examples, 
   &lt;1&gt; image information of a format unique to the image forming apparatus  1  scanned by the scanner unit  4  (for the purpose of plural times of printing or the like) and stored in the page memory  98  or the like to be copied, and 
   &lt;2&gt; image information of a format unique to the image forming apparatus  1  transmitted from an external PC or the like (for the purpose of plural times of printing or the like) and stored in the page memory  98  or the like to be printed. 
   The image information not to be set as an object of the file conversion processing is, as examples, 
   &lt;3&gt; image information scanned for the purpose of extraction by the scanner unit  4  of the image forming apparatus  1  and stored in the page memory  98  or the like in a file format such as JPEG or MMR, and 
   &lt;4&gt; image information acquired by the FAX unit  85  of the image forming apparatus  1  through a telephone line or the like as facsimile information and stored in the page memory  98  or the like in a file format such as MMR. 
   The application of the client PC  200  associated with the image forming apparatus  1  sends an exclusion request to the image forming apparatus such that the document is not changed by others (step S 12 ). 
   The image forming apparatus  1  performs document exclusion processing in response to this document exclusion request (step S 13 ) and, if the document exclusion processing is possible, sends an OK response to the client PC  200  (step S 14 ). 
   The client PC  200  inquires the image forming apparatus  1  whether the image processing unit  96  in the image forming apparatus  1  is usable (step S 15 ). As a result of this inquiry, when the image processing unit  96  in the image forming apparatus  1  is usable, the client PC  200  secures resources of the image processing unit  96  of the image forming apparatus  1  (step S 16 ). The image forming apparatus  1  returns a response indicating success in securing the resources of the image processing unit  96  to the application of the client PC  200  (step S 17 ). 
   The application of the client PC  200  issues a request for image processing by the image processing unit  96  to the image forming apparatus  1  (step S 18 ). On the other hand, the image forming apparatus  1  performs determination of a file format of the object image information (step S 19 ). 
   As described above, as examples, 
   &lt;1&gt; image information of a unique format scanned and stored to be copied, and 
   &lt;2&gt; image information of a unique format transmitted from the external PC or the like and stored to be printed 
   are set as file conversion objects. 
   Conversely, 
   &lt;3&gt; image information of JPEG, MMR, or the like scanned for the purpose of extraction, and 
   &lt;4&gt; image information of MMR or the like acquired as facsimile information 
   are not set as conversion objects. 
   When designated image information such as a document is set as an object of file conversion, the image forming apparatus expands and recompresses the designated image information and converts the image information into JPEG, MMR, or the like with the image processing unit  96  (step S 20 ). After the image conversion is finished using the image processing unit, the image forming apparatus releases the resources of the image processing unit (step S 21 ). 
   The image forming apparatus  1  returns a response indicating the finish of the image processing to the application side of the client PC  200  (step S 22 ). The application of the client PC  200  sends a data acquisition request to the image forming apparatus  1  (step S 23 ) and downloads the image information after the conversion of the file format into JPEG, MMR, or the like from the image forming apparatus  1  (step S 24 ). The application of the client PC  200  browses this image information of JPEG, MMR, or the like with the display unit  205  or the like and then stores the image information in the storing unit  204  or the like in an image format of PDF, TIFF, or the like (step S 25 ). 
   Thereafter, the application of the client PC  200  issues a request for releasing exclusion of the document. The image processing apparatus  1  releases the document exclusion processing (step S 27 ). When the image processing apparatus  1  reports the release of the document exclusion processing to the application of the client PC  200 , the processing ends (step S 28 ). 
   (Case in which File Conversion Processing is Performed in the Client PC:  FIG. 6 ) 
   A case in which file conversion is performed in the client PC because resources of the image processing unit cannot be secured in the image forming apparatus  1  will be explained. 
   First, when a document desired to be acquired among documents stored in the page memory  98  or the like of the image forming apparatus  1  is selected and a request for processing of the document is received from a user, the application of the client PC  200  associated with the image forming apparatus  1  performs conversion processing for a file format in a procedure described later (step S 31 ). 
   The application of the client PC  200  associated with the image forming apparatus  1  sends an exclusion request to the image forming apparatus such that the document is not changed by others (step S 32 ). The image forming apparatus  1  performs document exclusion processing in response to this document exclusion request (step S 33 ) and, if the document exclusion processing is possible, sends an OK response to the client PC  200  (step S 34 ). 
   The client PC  200  inquires the image forming apparatus  1  whether the image processing unit  96  in the image forming apparatus  1  is usable (step S 35 ). In response to this inquiry, the image forming apparatus  1  attempts to secure resources of the image processing unit  96  of the image forming apparatus  1  (step S 36 ). As a result, when it is impossible to secure the resources of the image processing unit  96  because, for example, the resources are in use, the image forming apparatus  1  returns an NG response indicating failure in securing of the resources of the image processing unit  96  to the application of the client PC  200  (step S 37 ). 
   In response, the application of the client PC  200  requests the image forming apparatus  1  to transfer the object image information without converting the image information (step S 38 ). In response to this request, the image forming apparatus  1  transfers the object image information to the client PC  200  without converting the object image information (step S 39 ). 
   Thereafter, the application of the client PC  200  performs determination of a file format of the object image information (step S 40 ). 
   As described above, as examples, 
   &lt;1&gt; image information of a unique format scanned and stored to be copied, and 
   &lt;2&gt; image information of a unique format transmitted from the external PC or the like and stored to be printed 
   are set as file conversion objects. 
   Conversely, 
   &lt;3&gt; image information of JPEG, MMR, or the like scanned for the purpose of extraction, and 
   &lt;4&gt; image information of MMR or the like acquired as facsimile information 
   are not set as file conversion objects. 
   When designated image information is set as an object of file conversion, the application of the client PC  200  expands and recompresses the designated image information such as a document and converts the image information into JPEG, MMR, or the like with the image processing unit  96  (step S 41 ). After browsing this image information of JPEG, MMR, or the like with the display unit  205  or the like, the application of the client PC  200  stores the image information in the storing unit  204  or the like in the image format of PDF, TIFF, or the like (step S 42 ). 
   Thereafter, the application of the client PC  200  issues a request for releasing exclusion of the document (step S 43 ). The image processing apparatus  1  releases the document exclusion processing (step S 44 ). When the image processing apparatus  1  reports the release of the document exclusion processing to the application of the client PC  200 , the processing ends (step S 45 ). 
   As described above, the image processing unit  96  of the image forming apparatus  1  subjects the image information (a document, etc.) of the unique format stored in the memory unit  98  or the like of the image forming apparatus  1  to file conversion. When it is impossible to use the image processing unit  96  because, for example, the image processing unit  96  is in use, the client PC  200  automatically performs file conversion. In this way, the image forming apparatus  1  or the client PC  200  is used according to a state of use to perform processing. According to such a load distributing function in the MFP and the PC, it is possible to surely browse image information desired to be browsed without being affected by the state of use. 
   According to the various embodiments described above, those skilled in the art can realize the invention. However, various modifications of these embodiments will readily occur to those skilled in the art. It is possible to apply the embodiments to various embodiments without any inventive ability. Therefore, the invention extends over a wide range not contradicting the disclosed principles and new characteristics and is not limited to the embodiments described above.