Abstract:
A reference chart including a plurality of patterns for sampling each of characteristic quantities indicating characteristics of a defective image is read by an image scanner targeted for checking, and image data is stored in a memory. An image analyzing section samples the characteristic quantity of each of the plurality of patterns expressed in the image data. Sampling of the characteristic quantities is hardly affected by a displacement between ideal image data and the above stored image data. A correlation table holding section holds a correlation table which associates each phenomenon name for classifying defective image and at lest one of the characteristics quantities corresponding to the phenomenon name. Referring to the correlation table, a phenomenon name specifying section specifies a phenomenon name of a pattern region in which the characteristic quantity is sampled by the characteristic quantity sampling section from among the plurality of patterns expressed in the image data.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an image checking system for checking a quality of image data read by a scanner, an image printed by a printer, or an image copied by a copying machine, and then, judging a state of the scanner, printer or copying machine from the check result.  
           [0002]    In general, the quality of an image formed by a copying machine or the like is judged by subjective check based on a comparison between the image and a defective image sample. Namely, in a field in which equipment such as a copying machine is practically used or in line check during equipment manufacture, a service man compares the image with a defect limit sample, for example, shown in a manual, thereby subjectively evaluating a defective image.  
           [0003]    In the above described field, when defective image is produced, the service man make checks as to what phenomenon occurs in the image by correlating it with a plurality of defective image samples presented in the manual. Thus, the check time or check precision greatly depend on the skillfulness of the service man. Namely, an unevenness occurs in a time required for checking, and judgment as to whether the image is defective or normal becomes subjective. Also, if it is not identified where the service man should make primary checks in a defective image sample, such defect cannot be found or amended at an earlier stage.  
           [0004]    Further, when a user makes a phone call to a service center during a failure, in general, the user does not have special knowledge of a copying machine. Thus, expressions of defectives are various, thus making it difficult to grasp what is the real cause of such defect from the telephone conversation.  
           [0005]    Such an automatic checking technique for a defective image is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-109807, for example, wherein checks based on a difference from reference data are made. That is, according to this document, a read image information (electronic data) obtained by reading a test pattern image by a scanner unit is compared with recording image information (electronic data) used for printing the test pattern image. If these images are detected to be inconsistent, they are judged to be defective, and recording conditions for recording paper are reset.  
           [0006]    In general, in such a method, a fine shift at a printout position, a skew, a distortion, or a change in multiplication occurs in an outputted image sample, making it impossible to adjust the positions of images to be compared between read image information and recording image information at a level of one pixel. Thus, even if it is detected that these images are inconsistent from each other at a character region for example, it is impossible to judge whether such inconsistency is caused by missing or by displacement in character regions which have been compared, by merely sampling differential data on these images. Thus, it is very difficult to precisely judge inconsistency, and such judgment is infeasible.  
           [0007]    On the other hand, another system for automatically making such image checks is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2000-132364. In this document, output image sample information is sent as image data to a control center, and the image is analyzed at the control center. However, a transfer rate of a current communication network is 64 Kbps in the case of an ISDN, for example. If image data is 210 MB, a time of 7 hours 20 seconds is required for transfer. Thus, image transfer is impossible at the transfer rate of the current communication network.  
           [0008]    Further, a copying machine and an intensive management apparatus for detecting an equipment malfunction are disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2000-81813. In this document, an equipment operation sound is sampled and analyzed. In the case of this document, an image itself is not analyzed, and thus, it is impossible to judge whether or not a problem actually appears on an image.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention has been made in order to solve the problem. An object according to one embodiment of the present invention is to provide an image checking system capable of automatically recognize a defective image, and specifying type of a phenomenon that occurs in an image. An object according to another embodiment of the present invention is to provide an image checking system capable of estimating where an equipment malfunction occurs from the phenomenon that occurs in such an image.  
           [0010]    According to one embodiment of the present invention, a reference chart including a plurality of patterns for sampling each of the characteristic quantities indicating characteristics of a defective image is read by an image scanner targeted for checking, and image data is stored in a memory. The characteristic quantity sampling section samples the characteristic quantities of each of the plurality of patterns expressed in the image data. The type of defective image is determined on the basis of the characteristic quantities. The characteristic quantities are characteristics obtained by processing the image data. These quantities include “insufficient resolution” and “brightening”, for example. The “brightening” indicates an average density of the image is lower than that of ideal image by more than a threshold. Such characteristic quantities are hardly affected by a displacement between the ideal image and the above stored image data.  
           [0011]    A correlation table associates each label for classifying defective image with at least one of the characteristic quantities corresponding to the label. By referring to the correlation table, a label specifying section specifies the label for a pattern region, in which the characteristic quantities are sampled by the characteristic quantity sampling section, of the plurality of patterns expressed in the read image data.  
           [0012]    A factor estimating section narrows candidates of the causes of a defect from the phenomenon of the thus analyzed defective image and any other information. These phenomenon and the causes of a defect are displayed at a display section.  
           [0013]    According to the present invention, image data is directly analyzed, thus making it possible to recognize a defect that occurs in an output image sample.  
           [0014]    The above described check processing is executed by a personal computer hand held by a service man, a personal computer connected to a copying machine via network, or a network computer or the like connected to the copying machine via network in the same manner.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a block diagram depicting a configuration of an image analyzing device according to one embodiment of the present invention;  
         [0016]    [0016]FIG. 2 shows an example of a reference chart;  
         [0017]    [0017]FIG. 3 shows an example of a reference chart characteristic list;  
         [0018]    [0018]FIGS. 4A to  4 C each show an example of various patterns assigned to each mesh of the reference chart;  
         [0019]    [0019]FIGS. 5A to  5 C are flowcharts showing a defective image checking process;  
         [0020]    [0020]FIG. 6 shows an example of a mesh characteristic quantity table;  
         [0021]    [0021]FIG. 7 shows an example of a correlation table;  
         [0022]    [0022]FIG. 8 shows an example of a chart instruction table;  
         [0023]    [0023]FIG. 9 is a flow chart showing another checking process;  
         [0024]    [0024]FIG. 10 is a sectional view showing an internal structure of a digital copying machine to which the present invention is applied;  
         [0025]    [0025]FIG. 11 is a block diagram depicting a configuration of a control system of the digital copying machine to which the present invention is applied;  
         [0026]    [0026]FIG. 12 is a flow chart showing an embodied operation applied to the copying machine of FIG. 11;  
         [0027]    [0027]FIG. 13 is a block diagram schematically depicting a configuration of an image checking system according to the present invention;  
         [0028]    [0028]FIG. 14 is a flow chart showing an embodied operation applied to the system of FIG. 13;  
         [0029]    [0029]FIG. 15 is a block diagram schematically depicting another configuration of the image checking system according o the present invention;  
         [0030]    [0030]FIG. 16 is a flow chart showing an embodied operation applied to the system of FIG. 15;  
         [0031]    [0031]FIG. 17 is a flow chart showing another embodied operation applied to the system of FIG. 15; and  
         [0032]    [0032]FIG. 18 is a flow chart showing still another embodied operation applied to the system of FIG. 15. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    Prior to giving a specific description of embodiments, a description of terms will be given. The terms used in the specification are defined as follows.  
         [0034]    Image sample: Image expressed on paper  
         [0035]    Image data: Electronic data expressing an image  
         [0036]    Image reading data: Image data of image sample obtained by reading the image sample by image reader device  
         [0037]    Output image sample: Image expressed on paper by outputting (printing) image data by image forming device  
         [0038]    Copy image sample: Image expressed on paper by copying image sample by image copying device (hereinafter, simply referred to “copying device”)  
         [0039]    Reference chart: Image on paper on which a specific pattern is expressed for defective image checking  
         [0040]    Reference data: Electronic data for the reference chart  
         [0041]    Reference chart characteristic list: List of data describing pattern configuration (or disposition) of the reference chart and characteristics (or pattern numbers) of each pattern  
         [0042]    Phenomenon name: Name, i.e., label for defective image specific to an image reader device, an image forming device, or a copying device  
         [0043]    (Examples) “image blurring” “main scanning black stripe” or “avalanche image” 
         [0044]    Image characteristic quantity (or simply characteristic quantity): quantity of characteristic that can be sampled by image processing, the characteristic quantity being judgment material or judgment element for phenomenon name  
         [0045]    (Examples) “darkening” “brightening”, “subs-canning” “stripe” or “non-uniformity” 
         [0046]    Correlation table: Table describing relationship between each set of image characteristic quantities and phenomenon name  
         [0047]    Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0048]    [0048]FIG. 1 is a block diagram depicting a configuration of an image analyzing device according to one embodiment of the present invention. This image analyzing device includes: an image reading section  61  that reads an image sample and produces electronic image data; an image data holding section  62  that holds the image data; an image analyzing section  63  that samples the image characteristic quantity; a chart characteristic holding section  64  that holds the reference chart characteristic list; a correlation holding section  65  that holds the correlation table for associating each set of image characteristic quantities and phenomenon name; a phenomenon name specifying section  66  for specifying the phenomenon name from the set of the image characteristic quantities and the correlation table; and an image data input/output section  67  for delivering image data between the image data holding section  62  and an external device. This image analyzing device, excluding the image reading section  61 , can be used as an application that a service man can install in a personal computer or a copying machine.  
         [0049]    Now, a variety of techniques for analyzing a defective image will be described.  
         [0050]    First, a technique for checking a defective image caused by an image reader device will be described below. Reference data corresponding to a reference chart is inputted in advance from the image data input/output section  67  to the image data holding section  62 . Also, a reference chart characteristic list is stored in advance in the chart characteristic holding section  64 .  
         [0051]    [0051]FIG. 2 shows an example of a reference chart. A reference chart  68  is finely divided into meshes each made of 50×50 pixels, for example, like a mesh  69 . This chart is formed in a single pattern in each mesh.  
         [0052]    [0052]FIG. 3 shows an example of a reference chart characteristic list. A reference chart characteristic list  73  includes a chart ID that identifies a reference chart; a chart type that identifies type of reference chart; the number of meshes; mesh size; and pattern numbers indicating a type of pattern assigned to each mesh. With respect to these pattern numbers, as shown in FIGS. 4A to  4 C,  1  is defined for a uniform pattern with density of 16, for example;  2  is defined for main scanning pair lines of a two-pixel cycle; and  3  is defined for a cross mark. These numbers are recorded corresponding to the coordinate of each mesh in the reference chart characteristic list  73 . Each pattern is suitable to sample different characteristic quantities. For example, a pattern of No.  1  is suitable to sample “darkening” or “brightening”, for example. The darkening used here indicates that the average density of image data is higher than that of reference data by more than a threshold. The brightening used here indicates that the average density of image data is lower than that of reference data by more than a threshold. A pattern of No.  2  is suitable to sample an “insufficient resolution”.  
         [0053]    [0053]FIG. 5A is a flow chart showing a method for checking a defective image caused by an image reader device (scanner). First, the reference chart  68  is read by an image reader device targeted for checking, and the obtained image read data is stored in the image data holding section  62  through the image data input section  67  (steps ST 001  and ST 002 ).  
         [0054]    The image analyzing section  63  samples an image characteristic quantity and creates a mesh characteristic quantity table by using the reference data and read image data stored in the image data storage section  62  and the reference chart characteristic list of FIG. 3 stored in the chart characteristic holding section  64 . FIG. 6 shows an example of a mesh characteristic quantity table  74 . In a mesh characteristic quantity table  74 , truth/false of each characteristic quantity is recorded corresponding to the coordinate of each mesh.  
         [0055]    For example, the image analyzing section  63  specifies the reference chart from a reference chart characteristic list  73  based on the chart ID described at a header section for reference data (step ST 003 ). Then, as in meshes  70   a  to  70   d  (FIG. 2), the crossing point coordinates of crosses of cross mark meshes are detected based on reference data and read image data respectively, and differences of the crossing point coordinates between the reference data and read image data are detected. Then, characteristic quantities of displacement, skew, and distortion (or magnification shift) are computed from the detected differences. If there is a characteristic quantity which is equal to or larger than a threshold, corresponding characteristic quantity in the mesh characteristic quantity table  74  is set to “truth(“1”)”. When at least one of these characteristic quantities (displacement, skew, and distortion) is “truth”, the image analysis is terminated.  
         [0056]    If all of the above characteristic quantities are smaller than thresholds, reference data and image data are roughly aligned each other according to the displacement quantity. Then the other characteristic quantities are sampled for each mesh, and the mesh characteristic quantity table  74  is continuously created (step ST 004 ). For example, like a mesh  71  (FIG. 2), in a mesh with high density and a uniform pattern (plain black), the density values of reference data and image data in 40×40 pixels at the center of the mesh in which an effect of displacement can be ignored are compared. If a density difference between reference data and image data exceeds a threshold, the image analyzing section  63  judges that an image brightening occurs, and the characteristic quantity of “brightening” in the mesh characteristic quantity table  74  is set as truth (“1”). As in the mesh  72 , in a pair line mesh, a density difference between a black stripe and a white stripe of image data is detected. If the difference is equal to or smaller than thresholds, the characteristic quantity of “insufficient resolution” is set as truth. Also, if the same characteristic quantity is sampled between continuous meshes in a subs-canning direction, the image analyzing section  63  sets the characteristic quantity of “sub-scanning” to truth.  
         [0057]    The phenomenon name specifying section  66  specifies a phenomenon name of a defective image from the thus obtained mesh characteristic quantity table  74  and the correlation table holding section  65  (ST 006 ). FIG. 7 shows an example of a correlation table. A correlation table  75  specifies a correlation between a phenomenon name and an image characteristic quantities. For example, “brightening”, “sub-scanning”, and “stripe” are described as the corresponding image characteristic quantities in the field of a phenomenon name “sub-scanning bright stripe copy”. The phenomenon name specifying section  66  diagnoses, i.e., specifies the phenomenon name of the mesh region as “sub-scanning bright stripe copy” if all of these characteristic quantities are set to truth.  
         [0058]    The phenomenon name “sub-scanning bright stripe copy” indicates that a stripe with its low density occurs in a sub-scanning direction. The “fog” indicates a defective image on which a plurality of small dots occur as a base of white like when newspaper is copied. The image characteristic quantity “subs-canning” indicates that a defective image occurs in the sub-scanning direction. The “small region” indicates a small dot.  
         [0059]    Now, a technique for checking a defective image caused by an image forming device (printer) will be described. As described previously, the reference data corresponding to a reference chart is inputted in advance from the image data input/output section  67  to the image data holding section  62 . Also the reference chart characteristic list  73  is stored in advance in the chart characteristic holding section  64 .  
         [0060]    [0060]FIG. 5B is a flow chart showing a method for checking a defective image caused by the image forming device. First, reference data is converted in accordance with an input format of the image forming device targeted for checking, and an image is outputted by an image forming device targeted for checking (step ST 011 ). Next, an output image sample is read by an image reading section  61 , and the read sample is stored in an image data holding section  62  (step ST 012 ). The subsequent processing is carried out in the same manner as that in image reader device check.  
         [0061]    Lastly, a technique for checking a defective image caused by a copying device will be described. As described previously, the reference data corresponding to a reference chart is inputted in advance from the image data input/output section  67  to the image data holding section  62 . Also, the reference chart characteristic list  73  is stored in advance in the chart characteristic holding section  64 .  
         [0062]    [0062]FIG. 5C is a flow chart showing a method of checking a defective image caused by the copying device. That is, a reference chart is copied by the copying device targeted for checking (step ST 021 ), the copied image sample is read by an image reading section  60 , and image read data is stored in the image data holding section  62  (step ST 022 ). The subsequent processing is carried out in the same manner as that in image reader device check.  
         [0063]    If the copying device targeted for checking can provides image read data from a scanner section to the outside, and a printer section can input image data from the outside, an image checking process is carried out separately for the scanner section and printer section, as shown in FIGS. 5 and 5B, and a phenomenon name for a respective one of these sections can be specified.  
         [0064]    Now, recheck based on the check result will be described.  
         [0065]    There is a case in which a phenomenon name cannot be specified completely by one check. For example, in the case of a sub-scanning bright stripe copy caused by fine dust adhered to an exposure laser unit, although a bright stripe appears in a unique pattern with its bright density, such a bright stripe can be filled in a plain dark pattern with very high density, and a defect cannot be detected. Namely, in the chart of FIG. 2, the above phenomenon appears only at a mesh  77  in a unique pattern with low density, and this phenomenon can not be appeared with the mesh  71  or  69 . Also, there exists a mesh in which it is impossible to judge whether or not image characteristic quantities appear continuously in a sub-scanning direction. A reference chart of an optimal pattern is automatically selected according to the image characteristic quantities obtained from the previous check result, and an instruction is given to an operator.  
         [0066]    [0066]FIG. 8 shows an example of a chart instruction table. A chart instruction table  76  describes the image characteristic quantity obtained as described above and the ID and chart name of a chart optimal to specify a possible phenomenon name from the characteristic quantity correspondingly. For example, checks are made by using the reference chart  68 , even when the check result is judged to be “normal” because of a set of the obtained characteristic quantities which are insufficient (for example, when two of the characteristic quantities corresponding to the phenomenon name “sub-scanning bright stripe copy” are sampled from the correlation table of FIG. 7), if a sub-scanning bright stripe copy potentially occurs, a “brightening”, “sub-scanning” and “stripe” is sampled in meshes of unique patterns with uniform low density.  
         [0067]    In such a case, in the present embodiment, the chart instruction table  76  is referred to based on the obtained characteristic quantities, and an instruction for an optimal chart is given to an operator. For example, even when the check result is judged to be “normal”, when a “brightening” or “sub-scanning” is sampled as a characteristic quantity in any mesh, a chart ID “003” is given to the operator. A subs-canning bright stripe copy can be reliably detected by using the reference chart of the chart ID “003”.  
         [0068]    Software according to the embodiment described above can be installed in a notebook type personal computer (PC) or the like hand held by a service man. The software is easily updated because the PC is not set up at a customer&#39;s site and is portable by service personnel. Also, a commercially available PC can be used, no problem occurs in CPU performance and main memory size, and there is no need to install the software in the customer&#39;s PC.  
         [0069]    Now, a checking process using an arbitrary image sample will be described.  
         [0070]    [0070]FIG. 9 is a flow chart showing this checking process. First, the image analyzing section  63  is initiated in an image sample analysis mode, and an arbitrary image sample is read by the image reading section  60  (step ST 031 ). The image read data is stored as new reference data in the image data holding section  62  together with a new chart ID that is not registered in the reference chart characteristic list  73  yet (step ST 032 ).  
         [0071]    In the image data holding section  62 , for example, a variety of patterns and their pattern numbers suitable to sample a variety of characteristic quantities as shown in FIG. 4 are stored as a pattern table. The image analyzing section  63  recognizes a pattern configuring the above new reference data, analyzes the configuration pattern and characteristics, and judges a correlation between such each pattern and the pattern in the above pattern table (step ST 033 ). Further, the image analyzing section  63  determines the contents of items such as number of meshes, mesh size, resolution, and configuration pattern, as shown in FIG. 3, for new reference data and adds the determined contents to the reference chart characteristic list  73  together with a new chart ID (step ST 034 ). The subsequent processing is identical to that shown in FIG. 5.  
         [0072]    Analysis of the configuration pattern is not always successful in all of the image samples, and all of the image samples cannot always be divided into clean meshes. Thus, only a useful region that has been successfully analyzed is used as a mesh. Thus, a number representing that the chart is specific chart in which meshes are arbitrarily patterned, is assigned as a chart type.  
         [0073]    In this way, an image checking process can be carried out by using an arbitrary image sample, thus making it unnecessary for the service man to manage a chart and making it possible for user to carry out maintenance or remote maintenance.  
         [0074]    Now, a description will be given with reference to a system for carrying out the above described image checking process, estimating the cause of a defect from the specified phenomenon name, and providing the estimation result. First, a description will be given with reference to a copying machine that carried out the image checking process.  
         [0075]    [0075]FIG. 10 is a sectional view showing an internal structure of a digital copying machine  200  to which the present invention is applied. In the digital copying machine  200 , there are provided a scanner section  201  that functions as a reading section described later and a printer section  203  that functions as an image forming section.  
         [0076]    On the top face of the digital copying machine  200 , there is provided a document base  20  that consists of a transparent glass on which a reading target, namely, a document D is placed. Also, on the top face of the digital copying machine  200 , there is arranged an automatic document feeder device (ADF)  21  that automatically feeds the document D onto the document base  20 . This ADF  21  is openably arranged relevant to the document base  20 , and functions as a document stop that brings the document D placed on the document base  20  into intimate contact with the document base  20 .  
         [0077]    The scanner section  201  arranged in the digital copying machine  200  has: an exposure lamp  25  serving as a light source that illuminate the document D placed on the document base  20 ; and a first mirror  26  that deflects the reflection light from the document D in a predetermined direction. These exposure lamp  25  and first mirror  26  are mounted on a first carriage  27  arranged downwardly of the document base  20 .  
         [0078]    The first carriage  27  is disposed movably in parallel to the document base  20 , and is reciprocally moved downwardly of the document base  20  by a driving motor  38  via meshed belt or the like (not shown).  
         [0079]    Further, a second carriage  28  that is movable in parallel to the document base  20  is arranged downwardly of the document base  20 . On the second carriage  28 , second and third mirrors  30  and  31  that sequentially deflect the reflection lights from the document D deflected by the first mirror  26  are mounted mutually vertically. The second carriage  28  is followed relevant to the first carriage  27  by a meshed belt or the like that drives the first carriage  27 , and is moved in parallel to the first carriage along the document base  20  at a velocity of ½.  
         [0080]    Downwardly of the document base  20 , there are arranged: a focusing lens  32  that focuses the reflection light from a third mirror  31  on the second carriage  28 ; and a CCD sensor  34  that receives the reflection light focused by the focusing lens  32  and converts the focused light in a photoelectric manner.  
         [0081]    On the other hand, the printer section  203  comprises a laser exposure device  40  that acts as an exposure scanner device. The laser exposure device  40  comprises: a semiconductor laser  41  serving as a light source; a polygon mirror  36  serving as a scanning member that continuously deflects laser lights emitted from the semiconductor laser  41 ; a polygon motor  37  serving as a scanning motor that rotatably drives the polygon mirror  36  in predetermined number of rotations; and a laser optical system  42  that deflects the laser light from the polygon mirror  36 , and guides the deflected light to a photosensitive drum  44 .  
         [0082]    The semiconductor laser  41  is controlled to be turned ON/OFF according to image information or the like of the document D read by the scanner section  201 . In the laser exposure device  40 , the laser light is oriented to the photosensitive drum  44  via the polygon mirror  36  and laser optical system  42 , and the peripheral face of the photosensitive drum  44  is scanned, whereby an electrostatic latent image is formed on the peripheral face of the photosensitive drum  44 .  
         [0083]    At the periphery of the photosensitive drum  44 , there are sequentially disposed: an electrification charger  45  that electrifies the peripheral face of the photosensitive drum  44  at a predetermined potential before an image is formed; a developer  46  that supplies a toner serving as a developing agent to a hidden electrostatic image formed on the peripheral face of the photosensitive drum  44 , thereby developing an image as a developing section at a desired image density; a release charger  47  for releasing an image forming medium, namely, copy paper P fed from a paper cassette described later from the photosensitive drum  44 ; a transfer charger  48  that transfers the toner image formed at the photosensitive drum  44  to the paper P; a release claw  49  that releases the copy paper P from the peripheral face of the photosensitive drum  44 ; a cleaner device  50  that cleans the residual toner on the peripheral face of the photosensitive drum  44 ; and a static eliminator  51  that statically eliminates the peripheral face of the photosensitive drum  44 . The above photosensitive drum  44  and a developing roller (not shown) or the like in the developer  46  are rotatably driven by a main motor  77 .  
         [0084]    At the lower part in the digital copying machine  200 , there are arranged in a laminate state: an upper cassette  52 , a middle cassette  53 , and a lower cassette  54  capable of being drawn from a device main body, respectively, and a large capacity feeder  55  is provided laterally. Copy papers P with their difference sizes or orientations are mounted in each of these cassettes. In the digital copying machine  200 , there is formed a carrying passage  58  extending through a transfer section positioned between the photosensitive drum  44  and a transfer charger  58  from such each cassette and the large capacity feeder  55 . At a terminal end of the carrying passage  58 , there is provided; a fixation device  43  having a fixation lamp  43  and a heat roller  43   b  in which heat is assigned by this fixation lamp  43   a . An exit  59  is formed on the side wall of the digital copying machine  200  opposed to the fixation device  43 , and a single tray finisher  57  is mounted on an exit  59 .  
         [0085]    [0085]FIG. 11 is a block diagram schematically depicting a configuration of a control system in the digital copying machine  200  to which the present invention is applied. FIG. 12 is a flow chart showing an operation of the present embodiment.  
         [0086]    The image data read by the scanner  201  is inputted to an image processing section  202 , and the inputted data is stored in a page memory (PM)  207  via a page memory controller (PM controller)  206 . A system CPU  205  is accessible to the PM  207  via the PM controller  206 .  
         [0087]    In an image check mode, when an operation of the copying machine  200  is started, as shown in FIG. 12, a defective image placed on the document base of the scanner  201  is read, and image data is stored in the PM  207  (steps ST 101  and ST 102 ). In this case, the defective image indicates an image recognized to be defective by a user due to an unnecessary dot on an image or dirt caused by a toner and the like or an image in which a defect does not occur evidently, the image being merely read for diagnosis. The defective image is a image sample obtained by copying , for example, the reference chart as shown in FIG. 2 by use of the copying machine  200 .  
         [0088]    The system CPU  205  samples a characteristic quantity in accordance with the above described image analyzing method, and, if a phenomenon (phenomenon name) is specified, stores the phenomenon in a memory (step ST 103 ). When the phenomenon is thus specified, the system CPU  205  judges the read image as a defective image (step ST 104 ).  
         [0089]    After a the defective image is judged, the system CPU  205  estimates the cause of a defect from internal parameters such as the values of a life counter stored in a register  211  (such as a use time of the copying apparatus  200  or a total time of rotation operation of the photosensitive drum  44 ) or error log (past error history) and the above specified phenomenon (step ST 105 ), displays the check result on a configuration panel  204 , or transmits the result to the outside via communication section  208  (step ST 106 ). An operator carries out maintenance work based on the check result.  
         [0090]    According to the present embodiment, investigation of the causes of a defect is carried out. The operator can identify where the defect occurs instead of whether or not a problem occurs in an image, thus facilitating work. Also, according to the present embodiment, an operation is closed in the copying machine, making it unnecessary to add a device for the purpose of checking.  
         [0091]    Now, a description will be given with respect to an image checking system for making checks by using a personal computer (PC) connected via an external interface.  
         [0092]    [0092]FIG. 13 is a block diagram schematically depicting a configuration of an image checking system according to the present embodiment. FIG. 14 is a flow chart showing an operation of the present embodiment.  
         [0093]    The image data read by a scanner  301  is inputted to an image processing section  302 , and the inputted data is stored in a PM  305  via PM controller  304 . The image data can be transferred to an external PC  400  through an interface with its high transfer rate (of 50 Mbytes/S, for example) such as an IEEE 1394 controller  307 , for example.  
         [0094]    After an image checking program installed in the PC  400  has been initiated, communication with a copying machine  300  is started, a control panel  308  makes a display so that an image targeted for checking is placed on a document base, and an operation of the scanner section is started (step ST 201 ). An operator places a defective image on a document base, presses a button for executing scanning or enter an execution command from an image quality check program of the PC  400 , thereby transferring image data to the PC  400  via the IEEE 1394 controller  307  (steps ST 203  and ST 204 ).  
         [0095]    When image data is transferred, the image quality check program installed in the PC  400  samples a character quantity in accordance with the above described image analyzing method, and, if a phenomenon (phenomenon name) is specified, stores the phenomenon in a memory (step ST 205 ). If the phenomenon is thus specified, the PC  400  judges the read image as a defective image (step ST 206 ).  
         [0096]    After a defective image is judged, the PC  400  estimates the cause of a defect from an ID of an image output device targeted for checking, the ID being inputted in advance, and the above specified phenomenon (step ST 207 ), displays the check result on a monitor  401  or a configuration panel  308  of the copying machine  300 , or transmits the result to the outside via communication section  402  (step ST 208 ). The operator carries out maintenance work based on the check result.  
         [0097]    Now, a description will be given with respect to an image check system that carries out checks in a network controller connected via network. The network controller has CPU performance equivalent to a commercially available PC and has a size equal to a main memory. Thus, a checking processing according to the present invention can be easily achieved.  
         [0098]    [0098]FIG. 15 is a block diagram schematically depicting a configuration of an image checking system according to the present embodiment. FIG. 16 is a flow chart showing an operation of the present embodiment.  
         [0099]    A copying machine  500  is connected to a network controller  600 , and image data can be inputted and outputted. In an image check mode, when an operation of the copying machine  500  is started, a defective image placed on the document base of a scanner  501  is read, and image data is stored in a main memory  603  in the network controller  600  (steps ST 301  and ST 302 ).  
         [0100]    The system CPU  601  samples a characteristic quantity in accordance with the above described image analyzing method, and, if a phenomenon (phenomenon name) is specified, stores the phenomenon in a memory (step ST 303 ). After the phenomenon is thus specified, the system CPU  205  judges the read image as a defective image (step ST 304 ).  
         [0101]    After the defective image is judged, the CPU  601  estimates the cause of a defect from output values of sensors  505  such as a temperature/humidity sensor mounted on the printer  503  or drum surface potential sensor and the above specified phenomenon (step ST 305 ). Then, the CPU displays the check result on a configuration panel  607  or a configuration panel  504  of the copying machine  500 . Alternatively, the CPU transmits the result to the outside via communication section  608  or displays the result on a monitor  701  of a PC  700  connected to a LAN via LAN controller  606  (step ST 306 ). An operator carries out maintenance work based on the check result.  
         [0102]    Now, an image checking system that makes checks by using a PC connected via LAN will be described.  
         [0103]    [0103]FIG. 15 is a block diagram schematically depicting a configuration of an image checking system according to the present embodiment. FIG. 17 is a flow chart showing an operation of the present embodiment.  
         [0104]    The copying machine  500  is connected to the network controller  600 , and image data can be inputted and outputted. After an image quality check program installed in the PC  700  connected to the LAN has been initiated, when communication with the copying machine  500  is started via the network controller  600 , a control panel  504  makes a display so that an image targeted for checking is placed on a document base, and an operation of a scanner section is started (step ST 401 ). An operator places a defective image on the document base, presses a button for executing scanning of the scanner  501  or inputs an execution command from an image quality check program of the PC  700 , thereby transferring the image data to the PC  700  via the network controller  600  (step ST 403  and ST 404 ).  
         [0105]    When the image data is transferred, the image quality check program installed in the PC  700  samples a characteristic quantity in accordance with the above described image analyzing method, and, if a phenomenon is specified, stores the phenomenon in a memory (step ST 405 ). When the phenomenon is thus specified, the PC  700  judges the read image as a defective image (step ST 406 ).  
         [0106]    After the defective image is judged, the PC  700  estimates the cause of a defect from the internal parameters stored in a register  508  in a system section  506  of the copying machine  500  and the above described phenomenon (step ST 407 ). Then, the PC displays the check result on a monitor  701 , a configuration panel  504 , or a configuration panel  607  or transmits the result to the outside via communication section  706  (step ST 408 ). An operator carries out maintenance work based on the check result.  
         [0107]    When a plurality of candidates for the causes of a defect exist in the step ST 407 , and such defect cannot be recovered by one work, the operator assigns a mark to an actually worked item of the work items in a work list of a check program displayed on the configuration panel  504 , and executes a checking scan again (step ST 410 ). The check program excludes the causes of a defect associated with the marked work item from a candidate for the causes of a defect, displays the new check result, and transmits the result. The operator carries out work in accordance with the new check result. This procedure is repeated until the cause of a defect has been clarified.  
         [0108]    Now, a description will be given with respect to an image checking system for making checks by using a network controller connected to a network, and estimating the causes of an error at a service center.  
         [0109]    [0109]FIG. 15 is a block diagram schematically representing a configuration of an image checking system according to the present embodiment. FIG. 18 is a flow chart showing an operation of the present embodiment.  
         [0110]    The copying machine  500  is connected to the network controller  600 , and image data can be inputted and outputted. In an image check mode, when an operation of the copying machine  500  is started, a defective image placed on the document base of the scanner  501  is read, and image data is stored in a main memory  603  in the network controller  600  (steps ST 501  and ST 502 ).  
         [0111]    The CPU  601  samples a characteristic quantity in accordance with the above described image analyzing method, and, if a phenomenon is specified, stores the phenomenon in a memory (step ST 503 ). When the phenomenon is thus specified, the CPU  601  judges the read image as a defective image (step ST 504 ).  
         [0112]    After a defective image is judged, phenomenon data passes through a communication network  800  via modem  608  or from a LAN controller  606  via router  703 , and is transmitted to a management PC  901  of a remote service center  900  (step ST 505 ).  
         [0113]    The management PC  901  having received the phenomenon data acquires associated data from the past check history of the copying machine or a data base  904  having stored therein a frequency of causes of a defect with the same model, and executes a program that estimates the causes of a defect from the above specified phenomenon and the associated data (step ST 506 ). Then, the PC displays the check result on a configuration panel  504 , a configuration panel  607 , or a monitor  701  via communication network  800  (step ST 508 ). An operator carries out maintenance work based on the check result. When the causes of a defect are thus estimated, check rules depending on environment or life and the like or information on problems with the same model and the like are flexibly assigned as an input.