PATENT DOCUMENT

Abstract:
A method for demanding a more flexible printing processing by an image forming apparatus which comprises a first storage section and a second storage section involves deciding whether to print the image information contained in the file; determining whether or not an image indicated by the emphasis information stored in the second storage section is contained in the image information contained in the file if the decision is carried out; creating a print command to print the image indicated by the emphasis information with a decolorable recording material in a case in which it is determined that the image indicated by the emphasis information is contained in the image information contained in the file; and sending the created print command through the communication section.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Division of application Ser. No. 15/210,000 filed Jul. 14, 2016, the entire contents of which are incorporated herein by reference. 
         [0002]    This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2015-151490, filed Jul. 31, 2015, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD 
       [0003]    Embodiments described herein relate generally to an image forming apparatus and a method for demanding a more flexible printing processing. 
       BACKGROUND 
       [0004]    As one type of an image forming apparatus, there is known an image forming apparatus equipped with a so-called image erasing apparatus that prints an image on a sheet with the use of a recording material, for example a decolorable toner, and furthermore carries out a decoloring processing on the toner used for forming the image through heating to erase the image printed on the sheet. In the image erasing apparatus, a reading section that reads the image in order to store the image before the image is erased and a decoloring section that decolors the toner for forming the image are comprised, and it is known to read the image again with the foregoing reading section to determine whether or not the decoloring processing of the toner is normally performed after the image is erased. In this way, at the time the image formed on the sheet is erased, a series of operations including reading and storing contents of the sheet with the reading section and decoloring the image are carried out. However, the contents printed on the sheet are various. Thus, there is a case in which in one sheet, a location at which a user wants to print the sheet with decolorable toner and a location at which the user wants to print the sheet with normal toner are mixed, and thus a more flexible printing processing is demanded. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a cross-sectional view schematically illustrating an image forming apparatus according to a first embodiment and a second embodiment; 
           [0006]      FIG. 2  is a block diagram illustrating the image forming apparatus according to the first embodiment and the second embodiment; 
           [0007]      FIG. 3  is a diagram schematically illustrating an image erasing apparatus according to the first embodiment and the second embodiment; 
           [0008]      FIG. 4  is a block diagram illustrating the image erasing apparatus according to the first embodiment and the second embodiment; 
           [0009]      FIG. 5  is a diagram schematically illustrating a bitmap image according to the first embodiment; 
           [0010]      FIG. 6  is a diagram schematically illustrating a bitmap image according to the first embodiment; 
           [0011]      FIG. 7  is a diagram schematically illustrating an emphasis information candidate file stored in an HDD of an MFP according to the first embodiment; 
           [0012]      FIG. 8  is a diagram schematically illustrating an emphasis information storage file stored in the HDD of the MFP according to the first embodiment; 
           [0013]      FIG. 9  is a flowchart illustrating a process of a print job according to the first embodiment; 
           [0014]      FIG. 10  is a diagram illustrating a copied document C according to the first embodiment and the second embodiment; 
           [0015]      FIG. 11  is a diagram illustrating a display example of a screen displayed on an operation panel according to the first embodiment; 
           [0016]      FIG. 12  is a flowchart illustrating a process of an erasing job according to the first embodiment; 
           [0017]      FIG. 13  is a diagram illustrating a sheet after erasing according to the first embodiment and the second embodiment; 
           [0018]      FIG. 14  is a diagram schematically illustrating connection of the MFP and a PC according to the second embodiment; 
           [0019]      FIG. 15  is a block diagram of the PC according to the second embodiment; 
           [0020]      FIG. 16  is a diagram schematically illustrating an emphasis information candidate file stored in an HDD of the PC according to the second embodiment; 
           [0021]      FIG. 17  is a diagram schematically illustrating an emphasis information storage area stored in the HDD of the PC according to the second embodiment; 
           [0022]      FIG. 18  is a diagram illustrating a display example of a screen displayed on a display section according to the second embodiment; and 
           [0023]      FIG. 19  is a flowchart illustrating a process of a print request job according to the second embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    In accordance with an embodiment, an image forming apparatus comprises a first storage section configured to store image information to be printed, a printing section configured to include a decolorable recording material and non-decolorable recording material and print an image based on the image information stored in the first storage section with the decolorable recording material in a case in which the image meets a predetermined condition, a second storage section configured to store emphasis information for emphasizing a specific image, and a control section configured to control the printing section to print an image indicated by the emphasis information stored in the second storage section with the decolorable recording material in a case in which the image meets the predetermined condition existing in the image information stored in the first storage section. 
         [0025]    Hereinafter, embodiments of the present invention are described with reference to the accompanying drawings. In the present embodiment, an MFP (Multi-Function Peripheral)  100  is described as an example of the image forming apparatus. 
         [0026]    In a first embodiment and a second embodiment, in a copied document C, as shown in  FIG. 10 , “A” meaning that a character is not emphasized, “B” meaning that a character is emphasized in bold type and “C” meaning that a character is emphasized with an underline are recorded. In the first embodiment, the document C refers to a sheet on which the image is formed. Further, in the second embodiment, the document C refers to a document file. As an example of a recording material, decolorable toner and non-decolorable toner are described as examples; however, the recording material is not limited to them. The recording material may be decolorable ink and non-decolorable ink. 
       First Embodiment 
       [0027]    The first embodiment is described with reference to  FIG. 1  to  FIG. 13 .  FIG. 1  is a cross-sectional view schematically illustrating an MFP  100  according to the first embodiment. The MFP  100  according to the first embodiment functions as the image forming apparatus. The MFP  100  shown in  FIG. 1  includes a scanner section  1 , a printer section  2 , an operation panel  4  and a system control section  5 . 
         [0028]    The scanner section  1  reads an image of a document to convert the image to image data. The scanner section  1  has the well-known configuration equipped with, for example, a CCD line sensor which converts the image of the document on a reading surface to the image data. The scanner section  1  may scan the document placed on a document table glass (not shown) or read the image of the document conveyed by an ADF (Auto Document Feeder). The scanner section  1  is arranged on the upper side of a main body of the MFP  100 , for example. The scanner section  1  is controlled by the system control section  5 . 
         [0029]    The printer section  2  forms an image on a sheet as an image receiving medium. In the present embodiment, the printer section  2  is an electrophotographic type image forming section. The printer section  2  forms the image with the use of five of plural types of toner (for example, yellow (Y) toner, cyan (C) toner, magenta (M) toner, black (K) toner and decoloring (D) toner, although any number of toners can be employed). The yellow (Y) toner, the cyan (C) toner, the magenta (M) toner and the black (K) toner are non-decolorable toner which cannot be decolored even if they are heated at a predetermined or higher fixing temperature. The decoloring toner (D) is decolorable toner which can be decolored through heating at a predetermined or higher temperature exceeding the fixing temperature. The color of the decoloring toner (D) is, for example, dark blue. Furthermore, details of the well-known configuration for carrying out generation of the image by the printer section  2  are described later. 
         [0030]    The decoloring toner used in the embodiment is formed by including a color material in binder resin, for example. The decolorable color material contains a color generation compound, a developer and a decoloring agent. As the color generation compound, for example, leuco dye is exemplified. As the developer, for example, phenols are exemplified. As the decoloring agent, a substance which is blended with the color generation compound if heated and does not have affinity to the developer is exemplified. The decolorable color material develops the color through interaction of the color generation compound and the developer, and can be decolored as the interaction of the color generation compound and the developer is cut off through the heating at a temperature equal to or higher than a decoloring temperature. 
         [0031]    In the configuration example shown in  FIG. 1 , the printer section  2  includes a paper feed cassette  20  ( 20 A,  20 B and  20 C) as a paper feed section. For example, each of the paper feed cassettes  20 A,  20 B and  20 C is arranged at the lower part of the main body of the MFP  100  in a detachable state. These paper feed cassettes  20 A,  20 B and  20 C respectively store sheets with different types (for example, different sizes and/or paper qualities) set respectively. It is also possible to set each of these paper feed cassettes  20 A,  20 B and  20 C to a paper feed cassette corresponding to each size after the sheets with different sizes are respectively housed in the paper feed cassettes  20 A,  20 B and  20 C, for example. A paper feed section sensor (not shown) is arranged in each of the paper feed cassettes  20 A,  20 B and  20 C. The paper feed section sensor detects the number of the sheets housed in a paper feed tray. The paper feed section sensor is, for example an infrared sensor. In addition, a mechanical sensor can also be used in which a well-known micro switch is arranged. The paper feed section sensor sends a detection result to a system control section  5  described later. Further, the printer section  2  may include a manual feed tray (not shown) as another paper feed section. 
         [0032]    Setting information relating to the sheets housed by each of the paper feed cassettes  20 A,  20 B and  20 C is stored in a non-volatile memory. The printer section  2  selects a paper feed cassette that houses sheets to be used in a printing processing according to the setting information. The printer section  2  prints an image on the sheet fed from the selected paper feed cassette. Furthermore, in a case in which the printer section  2  includes the manual feed tray, a size of a sheet set in the manual feed tray, which is input from the operation panel  4 , may be stored in the foregoing non-volatile memory. 
         [0033]    Furthermore, in the following description, as the sheet is conveyed from the paper feed section  20  to a paper discharge section  30 , the paper feed section  20  side is regarded as the upstream side with respect to a sheet conveyance direction, and the paper discharge section  30  side is regarded as the downstream side with respect to the sheet conveyance direction. 
         [0034]    A conveyance section  22  shown in  FIG. 1  conveys the sheet in the printer section  2 . The conveyance section  22  conveys the sheet supplied from the corresponding paper feed cassette  20 A,  20 B or  20 C through a pickup roller  21 A,  21 B or  21 C to a resist roller  24 . The resist roller  24  conveys the sheet to a transfer position at the timing when the image is transferred onto the sheet from an intermediate transfer belt  27  described later. 
         [0035]    Hereinafter, details of the image formation are described. As shown in  FIG. 1 , the image forming section  25 , an exposure section  26 , the intermediate transfer belt  27  and a transfer section  28  function as well-known image forming modules for forming an image. The image forming section  25  forms the image to be transferred onto the sheet. The configuration example of generating a color image shown in  FIG. 1  is described in detail later; however, an image forming section  25 Y forms an image corresponding to yellow with the yellow toner by color-separating a document image. An image forming section  25 M forms an image with the magenta toner similarly. An image forming section  25 C forms an image with the cyan toner. An image forming section  25 K forms an image with the black toner. Then, each of the image forming sections  25 Y,  25 M,  25 C and  25 K overlaps and transfers the toner image of each color onto the intermediate transfer belt  27 . On the other hand, the image forming section  25 D forms an erasable document image used in a case in which the sheet is reused with the decolorable toner. As stated above, the color of the decolorable toner is the dark blue. Thus, the image formed by the image forming section  25 D is a monochrome image. Each of the image forming sections  25 Y,  25 M,  25 C,  25 K and  25 D includes the well-known configuration constituted by, for example, a photoconductive drum, a charging charger, a developing section containing the toner, a charge removing section and the like (only shown in  FIG. 1 ). 
         [0036]    Each of the image forming sections  25 Y,  25 M,  25 C,  25 K and  25 D includes a well-known sensor such as a potential sensor and a density sensor (neither is shown). The potential sensor detects surface potential of the well-known photoconductive drum included in each image forming section. In each of the image forming sections  25 Y,  25 M,  25 C,  25 K and  25 D, the well-known charging charger charges the surface of the photoconductive drum before the photoconductive drum is exposed by the exposure section  26  described later. The system control section  5  can change a charging condition of the charging charger. The potential sensor detects the surface potential of the photoconductive drum of which the surface is charged by the charging charger. The density sensor detects density of the toner image transferred onto the intermediate transfer belt  27  described later. Further, the density sensor may detect density of the toner image formed on the photoconductive drum. 
         [0037]    The exposure section  26  forms an electrostatic latent image of the document image acquired by the scanner section  1  on the charged photoconductive drum of each of the image forming sections  25 Y,  25 M,  25 C,  25 K and  25 D through laser light as stated above. The electrostatic latent image formed on each photoconductive drum is an image to be developed with toner of each color. In other words, the exposure section  26  emits the laser light corresponding to each image forming section controlled according to the image data to each photoconductive drum via an optical system such as a polygon mirror. The exposure section  26  controls power of the laser light according to a control signal from the system control section  5 . The exposure section  26  also controls a modulation amount of a pulse width for controlling emission of the laser light according to a control signal from the system control section  5 . 
         [0038]    As stated above, each of the image forming sections  25 Y,  25 M,  25 C,  25 K and  25 D develops the electrostatic latent image formed on the individual photoconductive drum with the toner of each color by the developing section. Each of the image forming sections  25 Y,  25 M,  25 C,  25 K and  25 D forms the toner image as a visible image on the photoconductive drum. The intermediate transfer belt  27  is an intermediate transfer body. In a case in which the color image is formed with the foregoing non-decolorable toner, each of the image forming sections  25 Y,  25 M,  25 C and  25 K transfers (primarily transfers) the toner image formed on the photoconductive drum onto the intermediate transfer belt  27 . Specifically, each of the image forming sections  25 Y,  25 M,  25 C and  25 K applies transfer bias to the toner image at a primary transfer position. Each of the image forming sections  25 Y,  25 M,  25 C and  25 K controls the transfer bias through a transfer current. The toner image on each photoconductive drum is transferred onto the intermediate transfer belt  27  through the transfer bias at the individual primary transfer position (for example, a portion where the photoconductive drum is contacted with the transfer belt). The system control section  5  controls the transfer current used in a primary transfer processing by the image forming section. On the other hand, in a case in which the sheet is reused, in other words, in a case in which the monochrome image with the decolorable toner is formed, the toner image as the visible image is formed on the photoconductive drum by the image forming section  25 D. The toner image is transferred onto the intermediate transfer belt  27  as stated above. 
         [0039]    The transfer section  28  transfers the toner image on the intermediate transfer belt  27  onto the sheet at a secondary transfer position. The transfer section  28  includes a support roller  28   a  and a secondary transfer roller  28   b  arranged along a conveyance path of the sheet, and the secondary transfer position is a position where the support roller  28   a  and the secondary transfer roller  28   b  are opposite to each other across the intermediate transfer belt  27 . The transfer section  28  applies the transfer bias controlled by the transfer current to the intermediate transfer belt  27  at the secondary transfer position. The transfer section  28  transfers the toner image on the intermediate transfer belt  27  onto the sheet through the transfer bias. The system control section  5  controls the transfer current used in a secondary transfer processing. 
         [0040]    A fixing device  29  arranged at the downstream side of the foregoing transfer section  28  has a function of enabling the toner to be fixed on the sheet. For example, in the embodiment, the fixing device  29  enables the toner image to be fixed on the sheet through heat and pressure applied to the sheet. 
         [0041]    In the configuration example of  FIG. 1 , the fixing device  29  is composed of a heat roller (heating section)  29   b  in which a heating source  29   a  is built and a pressure roller (pressure section)  29   c  contacting therewith in a pressure state through a pressure mechanism (not shown). The heating source  29   a  may be a heater capable of controlling a temperature. For example, the heating source  29   a  may be constituted by a heater lamp such as a halogen lamp or may be an induction heating (IH) heater. Further, the heating source  29   a  may be constituted by a plurality of heaters. Furthermore, the fixing device  29  includes a temperature sensor (not shown) for measuring the temperature of the heat roller  29   b . The temperature sensor sends the temperature of the heat roller  29   b  to the system control section  5  described later. The pressure mechanism presses the pressure roller  29   c  to the heat roller  29   b . The pressure mechanism is constituted by an elastic member. In a case in which the pressure roller  29   c  is not pressed to the heat roller  29   b  by the pressure mechanism, the pressure roller  29   c  and the heat roller  29   b  are separated from each other, and a gap is formed between the pressure roller  29   c  and the heat roller  29   b.    
         [0042]    In a case of carrying out a fixing processing of enabling the toner image to be fixed on the sheet, the system control section  5  carries out control in such a manner that the temperature of the fixing device  29  becomes a predetermined fixing temperature. The fixing device  29  pressures the sheet on which the toner image is transferred by the transfer section  28  and heats the sheet at the fixing temperature. In this way, the fixing device  29  enables the toner image to be fixed on the sheet. Through a well-known branching mechanism (not shown) arranged at the downstream side of the fixing device  29 , the sheet to which the fixing processing is carried out is conveyed to either the paper discharge section  30  or an ADU (Automatic Duplex Unit)  31  in response to a processing request of a user. 
         [0043]    In a case in which the sheet to which the fixing processing is carried out by the fixing device  29  is discharged, the sheet is conveyed to the paper discharge section  30 . Further, in a case in which the image is also formed on the back surface of the sheet to which the fixing processing is carried out by the fixing device  29 , the sheet is switched back and then conveyed to the ADU  31  after temporarily conveyed to the paper discharge section  30  side. In this case, the ADU  31  supplies the sheet reversed through the switchback to the upstream side of the resist roller  24  again. 
         [0044]    The operation panel  4  is a user interface. The operation panel  4  includes well-known various input buttons and a display section  4   a  equipped with a touch panel  4   b . The system control section  5  controls contents displayed on the display section  4   a  of the operation panel  4 . The operation panel  4  outputs information input through the touch panel  4   b  or the input button of the display section  4   a  to the system control section  5 . Further, the operation panel  4  receives the input of information such as the number of printing sheets and density necessary for the printing at the time of the printing. An operator operates the operation panel  4  to select either a normal printing mode in which the printing is carried out with the non-decolorable toner or a part decoloring toner mode in which the printing is carried out with the decolorable toner and the non-decolorable toner. The operation panel  4  further includes a normal printing mode key (not shown) and a part erasing key (not shown). In a case of selecting the normal printing mode, the operator presses the normal printing mode key, and in a case of selecting the part decoloring toner mode, the operator presses the part erasing key. 
         [0045]    Next, the configuration of a control system of the MFP  100  is described.  FIG. 2  is a block diagram illustrating the MFP  100  of the present embodiment. A CPU (Central Processing Unit)  51 , a ROM (Read Only Memory)  53 , a RAM (Random Access Memory)  54 , an HDD (Hard Disk Drive)  55 , an external I/F (Interface)  56 , the scanner section  1 , the printer section  2  and the operation panel  4  are connected with one another via a system bus line  52 . The CPU  51 , the ROM  53  and the RAM  54  constitute the system control section  5 . 
         [0046]    A program executed by the CPU  51  and a threshold value are stored in the ROM  53  in advance. For example, the fixing temperature at which the fixation of the decolorable toner or the non-decolorable toner is possible is also stored the ROM  53 . 
         [0047]    In the RAM  54 , various memory areas such as an area in which a program executed by the CPU  51  is copied or decompressed and a working area serving as a job area of a data processing based on the program are dynamically formed. Further, the RAM  54  includes a temporary storage area for temporarily storing the image information of the document read by the scanner section  1  (the temporary storage area is equivalent to a first storage section). The image information has a bitmap image for each color of each toner to be used in the printing. As shown in  FIG. 5  and  FIG. 6 , the bitmap image divides the image information into a plurality of areas for each toner and has information indicating whether or not the toner is used in each area. In the present embodiment, there are the bitmap images of, for example, five types of toner including the yellow (Y) toner, the cyan (C) toner, the magenta (M) toner, the black (K) toner and the decoloring (D) toner. “1” meaning that the toner serving as an object is used in the area, and “0” meaning that the toner is not used in the area. A primary transfer is carried out on the basis of the bitmap image of each toner. 
         [0048]    The HDD  55  is a high capacity storage device. An OS (Operating System) for enabling the MFP  100  to operate is installed. In the HDD  55 , an emphasis information candidate file  55   a  shown in  FIG. 7  and an emphasis information storage file  55   b  shown in  FIG. 8  are stored. In the emphasis information candidate file  55   a , emphasis information indicating an object to be printed with the decolorable toner is stored at the time the part decoloring toner mode is selected. The emphasis information indicates, for example, bold type, underline, red character, number, italic, color painting, hatching and the like. The object indicated by the emphasis information is printed with the use of the decolorable toner. For example, in the document C as shown in  FIG. 10 , the characters of “B” represented by bold type and the characters of “C” represented by the underline are printed with the decolorable toner. 
         [0049]    Further, the emphasis information candidate file  55   a  is composed of an emphasis information column and an identifier column. The emphasis information column and the identifier column are a one-to-one relationship. The emphasis information is stored in the emphasis information column, and an identifier corresponding to the emphasis information is stored in the identifier column. The system control section  5  carries out management of the emphasis information through the identifier. 
         [0050]    In a case in which the part decoloring toner mode is selected, the system control section  5  refers to the emphasis information candidate file  55   a  to display the emphasis information stored in the emphasis information column of the emphasis information candidate file  55   a  and corresponding check boxes  4   a  on the operation panel  4 . A completion key  4   b  is displayed at the lower side of the operation panel  4 . If the check box  4   a  is checked and the completion key  4   b  is pressed by the operator, the system control section  5  reads out the emphasis information and the identifier corresponding to the checked check box  4   a  from the emphasis information candidate file  55   a  to store the read emphasis information and the identifier in the emphasis information storage file  55   b . The emphasis information storage file  55   b  which has the same structure as the foregoing emphasis information candidate file  55   a  includes the emphasis information column and the identifier column. The emphasis information checked by the check box  4   a  is stored in the emphasis information storage file  55   b . It is determined whether or not the emphasis information exists in the image information temporarily stored in the RAM  54  on the basis of the emphasis information stored in the emphasis information storage file  55   b  (the emphasis information storage file  55   b  is equivalent to a second storage section). 
         [0051]    The external I/F  56  is an interface for realizing communication of the system control section  5  with an external device. For example, the external I/F  56  receives print data in response to a print request from the external device, for example, a client terminal (PC). The external I/F  56  may be an interface for carrying out data communication with the external device, for example, may be a device (USB memory) locally connected with the external device or may be a network interface for realizing communication via a network. The external I/F  56  is equivalent to a communication section. 
         [0052]    As the scanner section  1 , the printer section  2  and the operation panel  4  are described above, the description thereof is omitted. 
         [0053]    Next, an image erasing apparatus  200  is described.  FIG. 3  is a schematic cross-sectional view of the image erasing apparatus  200  according to the present embodiment. The image erasing apparatus  200  erases an image of a sheet P as the image receiving medium on which the image is already formed to enable the sheet P to be reused. In the present embodiment, an erasing processing of decoloring the recording material through the heating and thus erasing the image is described as an example of the erasing processing. 
         [0054]    The image erasing apparatus  200  shown in  FIG. 3  includes a paper feed section  220  for housing the sheet P on which the image to be erased is printed, a first conveyance path  290  and a second conveyance path  295  for conveying the sheet P, a first reading section  232   a  and a second reading section  232   b  for reading the image of the sheet P, an erasing section  250  for decoloring the recording material used for forming the image of sheet P, conveyance rollers  286  arranged in each conveyance path, a first route change section  210  for switching a conveyance route of the sheet P, a paper discharge section  280  composed of a first paper discharge section  260  and a second paper discharge section  270  for storing the sheets P to which the processing is completed, and a second route change section  215  arranged in the first conveyance path  290  for switching the routes between the first paper discharge section  260  and the second paper discharge section  270 . The combination of the first conveyance path  290 , the second conveyance path  295  and the conveyance roller  286  is equivalent to a conveyance section. 
         [0055]    The paper feed section  220  houses the sheet P to be reused, on which the image is already formed. The sheet P is fed to the inside of the image erasing apparatus  200  in order to erase the image of the sheet P. The sheet P to be reused is a sheet P on which an image is formed with the toner capable of being decolored through the heating as the recording material. Further, the sheets P may have various sizes such as A3, A4, B5 and the like. The sheet feed section  220  includes a sheet feed tray  222  and a pickup roller  221  (hereinafter, referred to as a sheet feed tray pickup roller) for picking up the sheet P in the sheet feed tray  222 . The sheet feed tray  222  stacks the sheet P to which the erasure of the image is carried out. The sheet feed tray pickup roller  221  picks up the sheets P one by one from the sheet feed tray  222  to send the sheets P to the first conveyance path  290  in order. Further, a sheet feed section sensor (not shown), arranged in the sheet feed section  220 , is used to detect whether or not the sheet P exists in the sheet feed tray  222 . The sheet feed section sensor is, for example, an infrared sensor. In addition, a sensor using a well-known micro switch can also be used. The sheet feed section sensor sends a detection result to a control section  250  described later. 
         [0056]    The first conveyance path  290  and the second conveyance path  295  include a plurality of the conveyance rollers  286 . Each conveyance roller  286  is composed of a pair of a driving roller and a driven roller. 
         [0057]    The first reading section  232   a  and the second reading section  232   b  are arranged in the first conveyance path  290  along the conveyance path. The first conveyance path  290  conveys the sheet P from the sheet feed section  220  to the sheet discharge section  280  through the conveyance roller  286  via the first reading section  232   a  and the second reading section  232   b.    
         [0058]    In the present embodiment, as the sheet P is conveyed from the sheet feed section  220  to the sheet discharge section  280 , the sheet feed section  220  side is regarded as the upstream side with respect to the conveyance direction of the sheet P, and the sheet discharge section  280  side is regarded as the downstream side with respect to the conveyance direction of the sheet P. 
         [0059]    The first reading section  232   a  and the second reading section  232   b  each include, for example, a two-dimensional CCD scanner (the combination of the first reading section  232   a  and the second reading section  232   b  is equivalent to a reading section). The two reading sections  232   a  and  232   b , for example, are arranged at mutually different positions across the first conveyance path  290 . According to such a configuration, the first reading section  232   a  reads one side of the conveyed sheet P, and the second reading section  232   b  reads the other side opposite to the side read by the first reading section  232   a . The images read by the first reading section  232   a  and the second reading section  232   b , for example, are properly stored in an HDD  212  described later. 
         [0060]    The first conveyance path  290  is connected to the sheet discharge section  280  via a branch point B 1  positioned at the downstream side of the first reading section  232   a  and the second reading section  232   b  in the conveyance direction of the sheet P. As shown in  FIG. 3 , the second conveyance path  295  is connected with the branch point B 1 , and the first route change section  210  for switching the routes between the first conveyance path  290  and the second conveyance path  295  is arranged at the branch point B 1 . For example, it is set by default that the first route change section  210  allows the route for conveying the sheet P from the sheet feed section  220  to the sheet discharge section  280  via the first reading section  232   a  and the second reading section  232   b.    
         [0061]    In addition, the first conveyance path  290  is connected to the first paper discharge section  260  or the second paper discharge section  270  via a branch point B 2  located at the downstream side of the branch point B 1 . The second route change section  215  is connected with the branch point B 2  as shown in  FIG. 3 . It is set by default that the second route change section  215  allows the route for conveying the sheet P from the first route change section  210  to the first sheet discharge section  260 . 
         [0062]    In the present embodiment, a reusable sheet is conveyed to the first paper discharge section  260 , and a sheet which is unsuitable to be reused due to a reason such as dirt and the like is conveyed to the second paper discharge section  270 . 
         [0063]    The second conveyance path  295  is branched from the first conveyance path  290  at the branch point B 1  and merged with the first conveyance path  290  at a merging point G positioned at the upstream side of the first reading section  232   a  and the second reading section  232   b  in the first conveyance path  290  and at the downstream side of the sheet feed section  220 . 
         [0064]    The erasing section  250  is arranged in the second conveyance path between the branch point B 1  and the merging point G of the first conveyance path  290  and the second conveyance path  295 . The erasing section  250  includes a roller pair  251  and a heater  205  serving as a heating source. The heater  205 , for example, is arranged in at least one of rollers constituting the roller pair  251 . The roller pair  251  is heated by the heater  205 . In this way, in the erasing section  250 , through the heater  205 , the image of the sheet P formed with the decolorable toner is heated to the decoloring temperature (target temperature) via the roller pair  251  and the toner used for forming the image is decolored. Further, though not shown, a temperature sensor is arranged in the vicinity of the roller pair  251 . The temperature sensor measures the temperature of the roller pair  251  and sends a measured result to a control section  250  described later. 
         [0065]      FIG. 4  is a block diagram of the image erasing apparatus  200 . A CPU (Central Processing Unit)  201 , a ROM (Read Only Memory)  202 , a RAM (Random Access Memory)  203 , CCD sensors  204  constituting the first reading section  232   a  and the second reading section  232   b , the heater  205  of the erasing section  250 , an interface (I/F)  206  for carrying out data input and output with an external device such as a client terminal, a first route change driving section  207  for controlling the first route change section  210 , a second route change driving section  208  for controlling the second route change section  215 , a sheet conveyance motor  213  for driving various rollers, a sheet conveyance motor control driving section  209  for controlling the sheet conveyance motor  213 , an operation and display section  211  for carrying out the input and the display of various setting and the HDD  214  are connected with one another via a system bus line  201 . The CPU  201 , the ROM  202  and the RAM  203  constitute the control section  250 . 
         [0066]    The ROM  202  stores a program executed by the CPU  201  of the control section  250 . The ROM  202  further stores a threshold value of a printing rate of the image of the sheet and a threshold value of a density of the image of the sheet. The control section  250  determines whether or not the erasure is normally carried out on the basis of the two threshold values. In other words, the control section  250  determines whether or not the sheet can be reused. 
         [0067]    In the RAM  203 , various memory areas such as a working area serving as a job area of a data processing according to the program are dynamically formed. 
         [0068]    The CCD sensors  204  constituting the reading sections  232   a  and  232   b  are arranged as a row of line sensors (two-dimensional scanners) for reading the images of the sheet P to detect intensity of the surface of the sheet P with the conveyance of the sheet P. The CCD sensor  204  detects the intensity of the surface of the sheet P to read out or detect the image. The reading section  232  is not limited to the CCD sensor and may be a CMOS sensor. 
         [0069]    The heater  205  of the erasing section  250  uses, for example, an induction heating (IH) heater. As stated above, while the sheet P passes through the erasing section  250 , via the roller pair  251 , the heat from the heater  205  is indirectly applied to the sheet P to discolor the toner used for forming the image. The heater  205  may be optional as long as it can control the temperature. In addition to the induction heating heater, for example, a lamp heater such as a halogen lamp or infrared heater may be used. 
         [0070]    The operation and display section  211  which is, for example, a touch panel carries out the display and the input of information relating to operations of the image erasing apparatus  200 . In addition, the operation and display section  211  is an input section that includes various setting and instruction keys and inputs various operations. In a case of carrying out the erasure of the image, the operator operates a touch panel of the operation and display section  211 . For example, the operator presses a setting and instruction key (not shown) arranged on the touch panel to carry out the setting of the erasure in advance. In the present embodiment, in the erasing processing of the image, the sheet P is conveyed to the erasing section  250  after all the images of sheet P are read by the first reading section  232   a  and the second reading section  232   b . Then, the sheet P is discharged to the discharge section  280  after the sheet P is erased by the erasing section  250 . Furthermore, the operation and display section  211  includes a start key (not shown) for starting the erasing processing of the image. 
         [0071]    The control section  250  controls the first route change driving section  207  to drive the first route change section  210  to switch the position set by default to execute distribution so that the sheet P is conveyed from the first conveyance path  290  to the second conveyance path  295 . 
         [0072]    Further, the control section  250  controls the second route change driving section  208  to drive the second route change section  215  to distribute the sheet P to the first sheet discharge section  260  or the second sheet discharge section  270 . 
         [0073]    The HDD  212  at least includes a read image storage area for storing the image read by the CCD sensor  204  for the first time and a redetermination storage area for storing the image of the sheet to which the erasing processing is carried out by the erasing section  250 . 
         [0074]    In the MFP  100  and the image erasing apparatus  200  with the foregoing configurations, on the basis of the preset programs, the MFP  100  carries out the print job as shown in  FIG. 9 , and the image erasing apparatus  200  carries out the erasing job as shown in  FIG. 12 . 
         [0075]    Firstly, the print job carried out by the MFP  100  is described. At this time, the document C shown in  FIG. 10  is placed on the document table glass of the scanner section  1 . The MFP  100  reads the document C to copy it. As stated above, the characters of “B” in bold type and the characters of “C” with underline are recorded on the document C. The operator operates the operation panel  4  to press the part erasing key to copy the document C in the part decoloring toner mode. Further, the operator selects that the characters marked by bold type and underline are printed with the decolorable toner. 
         [0076]    The system control section  5  receives the input of a key signal of a part decoloring toner mode key through the operation panel  4  (ACT S 101 ). 
         [0077]    If the key signal of the part decoloring toner mode key is input, the system control section  5  displays the emphasis information stored in the emphasis information candidate file  55   a  of the HDD  55  on the operation panel  4  as shown in  FIG. 11 . Then, a random check is input to the check box  4   a  of the displayed emphasis information through the operation panel  4 . In the present embodiment, the checks are input to the check boxes of the underline and the bold type by the operator. Then, if a key signal of the completion key  4   b  is input to the system control section  5 , the system control section  5  reads out the selected emphasis information and the identifier from the emphasis information candidate file  55   a  to store the emphasis information and the identifier in the emphasis information storage file  55   b . In the present embodiment, the underline and the bold type are stored in the emphasis information column, and 0001 and 0002 serving as the identifiers of the underline and the bold type are stored in the corresponding identifier column (ACT S 102 ). 
         [0078]    Subsequently, the system control section  5  receives the input of printing information such as the number of printing sheets and printing magnification through the operation panel  4 . The input printing information is stored in a predetermined area of the RAM  54  (ACT S 103 ). 
         [0079]    The system control section  5  receives the input of a key signal of a start key through the operation panel  4 . The system control section  5  that receives the input of the key signal enables the scanner section  1  to operate to scan the document C placed on the document table glass. The system control section  5  stores the read image information of the document C in the temporary storage area of the RAM  54  (ACT S 104 ). 
         [0080]    Then, the system control section  5  determines whether or not the emphasis information stored in the emphasis information storage file  55   b  of the HDD  55  is stored in the image information stored in the temporary storage area of the RAM  54 . The determination is carried out in such a manner that the system control section  5  uses OCR (Optical Character Reader) software or carries out various processing such as macro recognition or micro recognition on the image information stored in the temporary storage area of the RAM  54  to analyze the image information stored in the temporary storage area of the RAM  54 . Then, the system control section  5  compares the analysis result with the content in the emphasis information storage file  55   b  of the HDD  55  to determine whether or not the emphasis information is recorded in the image information stored in the temporary storage area of the RAM  54 . In the present embodiment, the system control section  5  retrieves the characters recorded with underline and bold type from the image information stored in the temporary storage area of the RAM  54  (ACT S 105 ). 
         [0081]    If the system control section  5  determines that no emphasis information is recorded (No in ACT S 105 ), the image information stored in the temporary storage area of the RAM  54  is printed according to the printing information (the number of printing sheets and the printing magnification) stored in the RAM  54  (ACT S 107 ) and then the processing is terminated. 
         [0082]    On the other hand, if the system control section  5  determines that the emphasis information stored in the emphasis information storage file  55   b  of the HDD  55  is recorded (Yes in ACT S 105 ), in order to print the object indicated by the emphasis information with the decolorable toner, the bitmap image stored in the temporary storage area of the RAM  54  is rewritten. Specifically, the object (image information) printed with the decolorable toner as used in ACT S 105  described above is specified by the OCR software, the macro recognition or the micro recognition. Then, in the bitmap images as shown in  FIG. 5  and  FIG. 6 , areas serving as the objects of the cyan toner, the magenta toner, the yellow toner and the black toner are rewritten from “1” to “0” and an area serving as the object of the decolorable toner is rewritten from “0” to “1”. In the present embodiment, the bitmap image is changed in such a manner that the characters “B” formed in bold type and the characters “C” with underline are printed with the decolorable toner (ACT S 106 ). 
         [0083]    After that, the printer section  2  is used to print the image information stored in the temporary storage area of the RAM  54  according to the printing information stored in the RAM  54  (ACT S 107 ), and then the processing is terminated. Through these processing, on the sheet P serving as a copy of the document C shown in  FIG. 10 , the characters “B” and the characters “C” are printed with the decolorable toner. 
         [0084]    As stated above, if the part decoloring toner mode is selected, it is possible to automatically print locations where the bold characters or underlines, the red characters and the like are recorded with the use of the decolorable toner. 
         [0085]    Subsequently, the erasing job shown in  FIG. 12  is recorded. As a condition, the sheet P to be erased is set in the paper feed tray  222  of the paper feed section  220 . Then, the sheet P is printed in the above-mentioned part decoloring toner mode of the MFP  100 . The print content of the sheet P set in the paper feed tray  222  of the paper feed section  220  is identical to that shown in  FIG. 10 , and the characters “B” and the characters “C” recorded on the sheet P are printed with the decolorable toner. In the following processing, after the sheet P is read and stored, a processing of erasing the image on the sheet P is described as an example. The first route change section  210  is connected with the first conveyance path  290  and the paper discharge section  280  by default. 
         [0086]    Firstly, in ACT S 201 , the control section  250  controls the paper feed section  220  to feed the sheet P set in the paper feed tray  222  to convey the sheet P to the first conveyance path  290 . Specifically, the control section  250  picks up the sheets P set in the paper feed tray  222  one by one with the use of the paper feed tray pickup roller  221 . Then, the control section  250  controls the sheet conveyance motor control driving section  209  to activate the sheet conveyance motor  213  to drive the conveyance roller  286  to convey the sheet P in the first conveyance path  290 . 
         [0087]    After that, both sides of the sheet P are read by the first reading section  232   a  and the second reading section  232   b  arranged across the first conveyance path  290 , and the read images are stored in the read image storage area of the HDD  212  (ACT S 202 ). 
         [0088]    The first route change section  210  allows the default position of the route for conveying the sheet P from the paper feed section  220  to the paper discharge section  280 . Thus, before the reading processing, the control section  250  controls the first route change driving section  207  to drive the first route change section  210  to change the route to be capable of conveying the sheet P to the second conveyance path  295  via the branch point B 1 . In this way, the conveyance path from the second reading section  232   b  to the erasing section  250  is connected. 
         [0089]    The erasing section  250  is arranged in the second conveyance path  295 . The control section  250  conveys the sheet P to the erasing section  250  via the branch point B 1  of the first conveyance path  290  and the second conveyance path  295  (ACT S 203 ). The sheet P conveyed to the erasing section  250  is sandwiched by the roller pair  251  heated by the heater  205  to be conveyed. The image (toner) formed on the conveyed sheet P is heated by the erasing section  250 . Then, the temperature of the toner formed on the sheet P rises to the temperature set in ACT S 2  to be decolored. As stated above, in the present embodiment, the characters “B” and the characters “C” on the sheet P are formed with the decoloring toner. Thus, in the erasing section  250 , if the sheet P is heated by the heater  205 , the characters “B” and the characters “C” are erased (ACT S 204 ). 
         [0090]    The control section  250  conveys the sheet P to the first conveyance path  290  again via the merging point G of the first conveyance path  290  and the second conveyance path  295  at the upstream side of the first reading section  232   a  and the second reading section  232   b  (ACT S 205 ). 
         [0091]    The control section  250  controls the first reading section  232   a  and the second reading section  232   b  arranged in the first conveyance path  290  to read the surfaces of the sheet P of which the images are erased. The read images are stored in the redetermination storage area of the HDD  212  (ACT S 206 ). 
         [0092]    The control section  250 , with respect to the images stored in the redetermination storage area of the HDD  212 , refers to the threshold value of the printing rate of the sheet and the threshold value of the density stored in the ROM  202  to determine whether or not the sheet can be reused (ACT S 207 ). 
         [0093]    In a case in which the sheet P as shown in  FIG. 10  is erased, as there are many areas printed with the toner that cannot be erased, the control section  250  determines that the sheet P cannot be reused (No in ACT S 207 ). 
         [0094]    If the control section  250  determines that the sheet P cannot be reused (No in ACT S 207 ), the control section  250  controls the first route change driving section  207  and the second route change driving section  208  to drive the first route change section  210  and the second route change section  215  to switch the routes. Through the control, the sheet P can be conveyed to the second paper discharge section  270  via the branch points B 1  and B 2 . In this way, the conveyance path from the second reading section  232   b  to the second paper discharge section  270  is connected. If the conveyance path from the second reading section  232   b  to the second paper discharge section  270  is connected, the sheet P is conveyed to the second paper discharge section  270 . In this way, the sheet P that cannot be reused is housed in the second paper discharge section  270  (ACT S 209 ). 
         [0095]    On the other hand, a case in which all parts of the sheet are printed with the decolorable toner and the decolored sheet is in a good state is described. In this case, the control section  250  determines that the sheet can be reused (Yes in ACT S 207 ). If the control section  250  determines that the sheet can be reused, the control section  250  drives the first route change driving section  207  to switch the route. Through the control, the sheet can be conveyed to the first paper discharge section  260  via the branch point B 1 . In this way, the conveyance path from the second reading section  232   b  to the first paper discharge section  260  is connected. If the conveyance path from the second reading section  232   b  to the first paper discharge section  260  is connected, the sheet is conveyed to the first paper discharge section  260 . In this way, the reusable sheet is housed in the first paper discharge section  260  (ACT S 208 ). 
         [0096]    Through the foregoing configuration, as to document files created in various forms, it is possible to automatically print the emphasis information recorded on the sheet copied with the decolorable toner. For example, in order that document used in a conference can attract attention of a customer or a boss to achievement or selling points, there is a trend that important points of the document are added with underline or become bold type and are highlighted. The highlighted information is often important information. Therefore, the operator is possible to erase the important information (in other words, the emphasized information) in the document with an easy operation. In addition, in a case in which the sheet is erased by the image erasing apparatus, emphasized locations printed with the decolorable toner are erased and the image printed with the non-decolorable toner remains on the sheet without being erased as shown in  FIG. 13 . Then, the sheet after erased is read by the first reading section  232   a  and the second reading section  232   b  again. At this time, as the printing with the non-decolorable toner remains on the sheet, the sheet is automatically conveyed to the second paper discharge section  270  for disposal. In this way, the document of which the important information (in other words, the emphasized information) is erased is seldom recycled. 
         [0097]    Further, the emphasis information is exemplified as a location where the image is formed with the decoloring toner in each embodiment described above; however, the present invention is not limited to this. For example, it is also possible to register blue serving as the color of the decoloring toner in a file equivalent to the emphasis information candidate file  55   a . Then, in the part decoloring toner mode, if the color of the decoloring toner is selected and the copying is carried out on the screen shown in  FIG. 11 , in a case of the document on which the images formed with the decoloring toner and the non-decoloring toner are mixed is printed, the operator can acquire the sheet having the same configuration as the document serving as copy source. In other words, the operator can acquire the sheet identical to the copied document by forming the image formed with the use of the decoloring toner with the decoloring toner and forming the image formed with the use of the non-decoloring toner with the non-decoloring toner. 
         [0098]    For example, it is also possible to register ruled lines as a template in the file equivalent to the emphasis information candidate file  55   a . In this case, at the time the document is copied, at the registered ruled line part, the image is formed with the non-decoloring toner and the image other than that image formed with the non-decoloring toner is formed with the decoloring toner. In this way, the operator can repeatedly use only a predetermined template part by carrying out the decoloring processing. Further, in the foregoing embodiment, by changing the setting, for example, only the predetermined template part may be formed with the decoloring toner. 
       Second Embodiment 
       [0099]    Next, the second embodiment is described. The description of the same reference numerals of the MFP  100  and the image erasing apparatus  200  as those in the first embodiment is omitted. The external I/F  56  of the MFP  100  is the network interface for communication via the network. In the second embodiment, as shown in  FIG. 14 , a PC (Personal Computer)  300  and the MFP  100  are connected with the network via an LAN (Local Area Network)  305 . 
         [0100]    Further, in the second embodiment, an emphasis information candidate file  353   a  as shown in  FIG. 16  and an emphasis information candidate area  353   b  (a storage area of the emphasis information candidate area  353   b  is equivalent to a second storage section) as shown in  FIG. 17  are held in an HDD  358  of the PC  300 . The emphasis information candidate file  353   a  and the emphasis information candidate area  353   b  are equivalent to the emphasis information candidate file  55   a  and the emphasis information storage file  55   b  stored in the HDD  55  of the MFP  100 . The emphasis information candidate file  353   a  and the emphasis information candidate file  55   a  have a correspondence relationship, and the emphasis information candidate area  353   b  and the emphasis information storage file  55   b  also have a correspondence relationship. 
         [0101]    A block diagram of the PC  300  is shown in  FIG. 15 . A CPU  351 , a ROM  353 , a RAM  354 , a display section  355 , an operation device  356 , an external I/F  357  (equivalent to a communication section) and the HDD  358  are connected with one another via the system bus line  352 . Further, the CPU  351  the ROM  353  and the RAM  354  constitute a control section  350 . 
         [0102]    A program for enabling the control section  350  to operate and a threshold value are stored in the ROM  353  in advance. 
         [0103]    In the RAM  354 , a memory area serving as a working area of a data processing according to the program is dynamically formed. Further, a mode management flag is stored in the RAM  354 . In a case in which the part decoloring toner mode is selected, “1” is set in the mode management flag, and in a case in which the part decoloring toner mode is not selected, “0” is set in the mode management flag. 
         [0104]    The display section  355  is a device for displaying information to the operator. 
         [0105]    The operation device  356  is a device such as a key board, a mouse and the like for inputting necessary information to the PC  300 . 
         [0106]    The external I/F  357  is an interface for communicating with the external device. For example, the external I/F  357  is the network interface for communication via the network. The external I/F  357  receives or sends data from or to the MFP  100 . 
         [0107]    The HDD  358  is a high capacity storage device. An OS (Operating System) for enabling the PC  300  to operate is installed in the HDD  358 . Further, a printer driver serving as software for printing a document file by the MFP  100  is also installed in the HDD  358 . The emphasis information candidate file  353   a  and the emphasis information candidate area  353   b  described above are stored in the HDD  358  as a part of the printer driver. Further, the HDD  358  also stores the document file the operator wants to print (an area for storing the document file to be printed is equivalent to a first storage section). 
         [0108]    In a case in which the document file stored in the HDD  358  is printed, a print command described in a page description language such as postscript data is used. The printer driver creates the print command described in the page description language on the basis of the content of the document file. The page description language refers to a program language for instructing the MFP  100  at the time a document or an image created on a computer is printed with the MFP  100 . In the page description language, position information and blank form information (font color, underline, bold type) of characters or figures are recorded. When the document file is printed with the MFP  100 , a bitmap image is created on the basis of the description of the page description language of the received print command. Then, in the second embodiment, the control section  350  determines the emphasis information to print with the decolorable toner on the basis of the content described in the page description language. 
         [0109]    In a case in which the printing is carried out with the printer driver, a part printing mode can be selected. In a case in which the part printing mode is selected, it is possible to select the part printing mode by checking a radio button from a GUI (Graphical User Interface) screen (not shown), displayed on a display device  355 , which is generated by the printer driver as an example. If the part printing mode is selected, a processing is carried out in such a manner that the object indicated by the emphasis information is printed with the decolorable toner. A printing key is displayed on the GUI of the printer driver. In a case in which the part printing mode is selected, the GUI screen is switched to a screen for selecting the emphasis information by pressing the displayed printing key. On the other hand, in a case in which the part printing mode is not selected, if the printing key is pressed, a processing in which the print command is not rewritten is carried out. 
         [0110]    With a key signal of the printing key input, a screen as shown in  FIG. 18  separately from the GUI screen is opened. As shown in  FIG. 18 , the emphasis information stored in the emphasis information column of the emphasis information candidate file  353   a  and the corresponding check box  355   a  are displayed on the display section  355 . Further, a completion key  355   b  is displayed at the lower side of the display section  355 . If a check box  355   a  is checked by the operator and the completion key  355   b  is pressed, the control section  350  reads out the emphasis information and the identifier corresponding to the checked check box  355   a  from the emphasis information candidate file  353   a  to store the emphasis information and the identifier in the emphasis information candidate area  353   b.    
         [0111]    In the PC  300  with the foregoing configuration, the control section  350  executes a print request job shown in  FIG. 19  according to a preset program. At this time, the MFP  100  and the PCs  300  are connected with each other as shown in  FIG. 14 . The document file as shown in  FIG. 10  is created with the document software and the printing is carried out. Further, in the default setting already, “1” is stored in the mode management flag of the RAM  354 , and the part printing mode is selected. Further, it is set that the printer driver uses the black toner in in the default setting. In the print request job, the document file as shown in  FIG. 10  is printed. In other words, the characters of “B” in bold type and the characters of “C” with underline are recorded in the document file. The operator operates the operation panel  4  to press the part erasing key to carry out the copying in the part decoloring toner mode. Further, the operator selects the characters marked by the bold type and the underline to print them with the decolorable toner. 
         [0112]    The GUI screen for printing generated by the printer driver is displayed on the display device  355 . The printing key is displayed on the GUI screen. Further, on the GUI screen, a check is already input to the part printing mode. The control section  350  receives the input of the key signal of the printing key. The control section  350  refers to the mode management flag to confirm that “1” is stored in the RAM  354 . If the control section  350  confirms that the part printing mode is selected, the emphasis information in the emphasis information candidate file  353   a  is displayed on the display section  355  as shown in  FIG. 18 . Then, a random check is input to the check box  355   a  at the left side of the displayed emphasis information via the display section  355 . In the present embodiment, checks are input to the check boxes of the underline and the bold type (ACT S 301 ). 
         [0113]    Then, if the completion key  355   b  is pressed, the control section  350  reads out the selected emphasis information from the emphasis information candidate file  353   a  to store the emphasis information in the emphasis information candidate area  353   b . In the present embodiment, the underline and the bold type are stored in the emphasis information column, and 0001 and 0002 serving as the identifiers of the underline and the bold type are stored in the corresponding identifier columns (ACT S 302 ). 
         [0114]    After that, the control section  350  creates the print command according to the page description language on the basis of the document file serving as the object (ACT S 303 ). 
         [0115]    After the print command is created, the control section  350  determines whether or not the emphasis information stored in the emphasis information candidate area  353   b  of the HDD  358  exists in the created print command (ACT S 304 ). 
         [0116]    If it is determined that the emphasis information does not exist in the print command (No in ACT S 304 ), the control section  350  sends the print command created in ACT S 303  to the MFP  100  via the external I/F  357  (ACT S 306 ). 
         [0117]    On the other hand, if it is determined that the emphasis information exists in the print command (Yes in ACT S 304 ), the control section  350  rewrites the print command created in ACT S 303  to carry out a processing of creating a print command again. As stated above, the print command is recorded in the page description language, and the position information and the blank form information (font size, presence or absence of the bold type and the underline) of the characters or the figures of the document file to be printed are recorded in the page description language. The control section  350  retrieves the emphasis information stored in the emphasis information candidate area  353   b  of the HDD  358  from the print command and rewrites the color of the character of the blank form information at a corresponding location to print the location with the decolorable toner to create a print command (ACT S 305 ). The creation of the print command in ACT S 305  also contains amendment or rewriting of the foregoing print command created in ACT S 303 . In the present embodiment, the control section  350  retrieves the presence or absence of the bold type and the underline from the print command and rewrites the print command to print the corresponding location with the decolorable toner. 
         [0118]    Then, the control section  350  sends the print command to the MFP  100  via the external I/F  357  (ACT S 306 ) and then terminates the processing. Further, if the MFP  100  receives the print command, the control section  350  creates image data according to the print command to carry out the printing processing. 
         [0119]    The sheet printed by the MFP  100  is erased by the image erasing apparatus  200  as stated in the first embodiment. Further, the erasure of the image in the second embodiment is identical to that in the first embodiment, and thus the description thereof is omitted. 
         [0120]    Through the above, as to the document files created in various forms, it is possible for the operator to automatically print the important information (emphasized information) recorded on the sheet to be copied with the decolorable toner without carrying out a complicated setting process. When the document file is created, if the locations the operator wants to erase are created with the underline and the bold type, it is possible for the operator to cancel any location with the easy operation. In other words, in a process of creating a document for conference or a document for presentation, it is possibly set for the MFP  100  to automatically print the location (in other words, the important information) emphasized spontaneously with the decolorable toner, and the burden of the operator, in other words, the operator is aware of locations he/she wants to erase to create a document, is reduced. 
         [0121]    In the first embodiment, the image information is acquired from the scanner section  1 ; however, for example, the image information may be received through the communication from the external I/F. 
         [0122]    In the second embodiment, after the print command created in the page description language is created, the rewriting is carried out; however, for example, at the stage of creating the print command in the page description language, after the character information of the document file is analyzed to determine whether or not the emphasis information is stored in the document file, the print command may be created in the page description language to print the document file with the decolorable toner initially. 
         [0123]    In the second embodiment, in the part decoloring toner mode, after converting the print command created in the page description language, the PC  300  sends the converted print command to the MFP  100 . However, it is certainly considered to rewrite the print command with the MFP  100  without rewriting the print command with the PC  300 . In this case, for example, a flag indicating the printing is in the part decoloring toner mode is recorded in the print command in advance. Then, after the MFP that receives the print command confirms the flag, a rewriting processing to print the emphasis information stored by the print command from the emphasis information candidate area  353   b  stored in the HDD with the decolorable toner may be carried out. 
         [0124]    The first storage section and the second storage section may be formed integrally or separately. 
         [0125]    Further, in the present embodiment, it is described that the color of the image is erased as an example of the erasing processing; however, the method of erasing the image is not limited to this. In other words, the image erasing apparatus recorded in the present embodiment is not limited to an apparatus for erasing the color of the image through the heating. For example, the image erasing apparatus may be an apparatus for decoloring the color of the image on the sheet through irradiation of light or an apparatus for erasing the image formed on the sheet by using chemicals and the like. The image erasing apparatus may be optional apparatus as long as it enables the image on the sheet to be invisible in order to be capable of reusing the sheet. 
         [0126]    While certain embodiments are described, these embodiments are presented by way of example only, and are not intended to limit the scope of the invention. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.